[PATCH v3] platform: chrome: Add ChromeOS EC ISHTP driver

[PATCH v3] platform: chrome: Add ChromeOS EC ISHTP driver

[Rushikesh S Kadam]

This driver implements a slim layer to enable the ChromeOS
EC kernel stack (cros_ec) to communicate with ChromeOS EC
firmware running on the Intel Integrated Sensor Hub (ISH).

The driver registers a ChromeOS EC MFD device to connect
with cros_ec kernel stack (upper layer), and it registers a
client with the ISH Transport Protocol bus (lower layer) to
talk with the ISH firwmare. See description of the ISHTP
protocol at Documentation/hid/intel-ish-hid.txt

Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
---

v3
 - Made several changes to improve code readability. Replaced
   multiple cl_data_to_dev(client_data) with dev variable. Use
   reverse Xmas tree for variable defintion where it made sense.
   Dropped few debug prints. Add docstring for function
   prepare_cros_ec_rx().
 - Fix code in function prepare_cros_ec_rx() under label
   end_cros_ec_dev_init_error.
 - Recycle buffer in process_recv() on failing to obtain the
   semaphore.
 - Increase ISHTP TX/RX ring buffer size to 8.
 - Alphabetically ordered CROS_EC_ISHTP entries in Makefile and
   Kconfig.
 - Updated commit message.

v2
 - Dropped unused "reset" parameter in function cros_ec_init()
 - Change driver name to cros_ec_ishtp to be consistent with other
   references in the code.
 - Fixed a few typos. 

v1
 - Initial version

 drivers/platform/chrome/Kconfig         |  13 +
 drivers/platform/chrome/Makefile        |   1 +
 drivers/platform/chrome/cros_ec_ishtp.c | 765 ++++++++++++++++++++++++++++++++
 3 files changed, 779 insertions(+)
 create mode 100644 drivers/platform/chrome/cros_ec_ishtp.c

diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 16b1615..5848179 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -62,6 +62,19 @@ config CROS_EC_I2C
 	  a checksum. Failing accesses will be retried three times to
 	  improve reliability.
 
+config CROS_EC_ISHTP
+	tristate "ChromeOS Embedded Controller (ISHTP)"
+	depends on MFD_CROS_EC
+	depends on INTEL_ISH_HID
+	help
+	  If you say Y here, you get support for talking to the ChromeOS EC
+	  firmware running on Intel Integrated Sensor Hub (ISH), using the
+	  ISH Transport protocol (ISH-TP). This uses a simple byte-level
+	  protocol with a checksum.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cros_ec_ishtp.
+
 config CROS_EC_SPI
 	tristate "ChromeOS Embedded Controller (SPI)"
 	depends on MFD_CROS_EC && SPI
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index cd591bf..4efe102 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -7,6 +7,7 @@ cros_ec_ctl-objs			:= cros_ec_sysfs.o cros_ec_lightbar.o \
 					   cros_ec_vbc.o cros_ec_debugfs.o
 obj-$(CONFIG_CROS_EC_CTL)		+= cros_ec_ctl.o
 obj-$(CONFIG_CROS_EC_I2C)		+= cros_ec_i2c.o
+obj-$(CONFIG_CROS_EC_ISHTP)		+= cros_ec_ishtp.o
 obj-$(CONFIG_CROS_EC_SPI)		+= cros_ec_spi.o
 cros_ec_lpcs-objs			:= cros_ec_lpc.o cros_ec_lpc_reg.o
 cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC)	+= cros_ec_lpc_mec.o
diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c
new file mode 100644
index 0000000..b1d19c4
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_ishtp.c
@@ -0,0 +1,765 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ISHTP client driver for talking to the Chrome OS EC firmware running
+ * on Intel Integrated Sensor Hub (ISH) using the ISH Transport protocol
+ * (ISH-TP).
+ *
+ * Copyright (c) 2019, Intel Corporation.
+ */
+
+#include <linux/delay.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/intel-ish-client-if.h>
+
+/*
+ * ISH TX/RX ring buffer pool size
+ *
+ * The AP->ISH messages and corresponding ISH->AP responses are
+ * serialized. We need 1 TX and 1 RX buffer for these.
+ *
+ * The MKBP ISH->AP events are serialized. We need one additional RX
+ * buffer for them.
+ */
+#define CROS_ISH_CL_TX_RING_SIZE		8
+#define CROS_ISH_CL_RX_RING_SIZE		8
+
+/* ISH CrOS EC Host Commands */
+enum cros_ec_ish_channel {
+	CROS_EC_COMMAND = 1,			/* AP->ISH message */
+	CROS_MKBP_EVENT = 2,			/* ISH->AP events */
+};
+
+/*
+ * ISH firmware timeout for 1 message send failure is 1Hz, and the
+ * firmware will retry 2 times, so 3Hz is used for timeout.
+ */
+#define ISHTP_SEND_TIMEOUT			(3 * HZ)
+
+/* ISH Transport CrOS EC ISH client unique GUID */
+static const guid_t cros_ish_guid =
+	GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
+		  0xb0, 0xd8, 0x9e, 0x7c, 0xda,	0xe0, 0xd6, 0xa0);
+
+struct header {
+	u8 channel;
+	u8 status;
+	u8 reserved[2];
+} __packed;
+
+struct cros_ish_out_msg {
+	struct header hdr;
+	struct ec_host_request ec_request;
+} __packed;
+
+struct cros_ish_in_msg {
+	struct header hdr;
+	struct ec_host_response ec_response;
+} __packed;
+
+#define IN_MSG_EC_RESPONSE_PREAMBLE					\
+	offsetof(struct cros_ish_in_msg, ec_response)
+
+#define OUT_MSG_EC_REQUEST_PREAMBLE					\
+	offsetof(struct cros_ish_out_msg, ec_request)
+
+#define cl_data_to_dev(client_data) ishtp_device((client_data)->cl_device)
+
+/*
+ * The Read-Write Semaphore is used to prevent message TX or RX while
+ * the ishtp client is being initialized or undergoing reset.
+ *
+ * The readers are the kernel function calls responsible for IA->ISH
+ * and ISH->AP messaging.
+ *
+ * The writers are .reset() and .probe() function.
+ */
+DECLARE_RWSEM(init_lock);
+
+/**
+ * struct response_info - Encapsulate firmware response related
+ *			information for passing between function
+ *			ish_send() and process_recv() callback.
+ * @data:		Copy the data received from firmware here.
+ * @max_size:		Max size allocated for the @data buffer. If the
+ *			received data exceeds this value, we log an
+ *			error.
+ * @size:		Actual size of data received from firmware.
+ * @error:		0 for success, negative error code for a
+ *			failure in function process_recv().
+ * @received:		Set to true on receiving a valid firmware
+ *			response to host command
+ * @wait_queue:		Wait queue for Host firmware loading where the
+ *			client sends message to ISH firmware and waits
+ *			for response
+ */
+struct response_info {
+	void *data;
+	size_t max_size;
+	size_t size;
+	int error;
+	bool received;
+	wait_queue_head_t wait_queue;
+};
+
+/**
+ * struct ishtp_cl_data - Encapsulate per ISH TP Client.
+ * @cros_ish_cl:	ISHTP firmware client instance.
+ * @cl_device:		ISHTP client device instance.
+ * @response:		Firmware response information for passing
+ *			between function ish_send() and process_recv()
+ *			callback.
+ * @work_ishtp_reset:	Work queue reset handling.
+ * @work_ec_evt:	Work queue for EC events.
+ * @ec_dev:		CrOS EC MFD device.
+ *
+ * This structure is used to store per client data.
+ */
+struct ishtp_cl_data {
+	struct ishtp_cl *cros_ish_cl;
+	struct ishtp_cl_device *cl_device;
+
+	/*
+	 * Used for passing firmware response information between
+	 * ish_send() and process_recv() callback.
+	 */
+	struct response_info response;
+
+	struct work_struct work_ishtp_reset;
+	struct work_struct work_ec_evt;
+	struct cros_ec_device *ec_dev;
+};
+
+/**
+ * ish_evt_handler - ISH to AP event handler
+ * @work:		Work struct
+ */
+static void ish_evt_handler(struct work_struct *work)
+{
+	struct ishtp_cl_data *client_data =
+		container_of(work, struct ishtp_cl_data, work_ec_evt);
+	struct cros_ec_device *ec_dev = client_data->ec_dev;
+
+	if (cros_ec_get_next_event(ec_dev, NULL) > 0) {
+		blocking_notifier_call_chain(&ec_dev->event_notifier,
+					     0, ec_dev);
+	}
+}
+
+/**
+ * ish_send() - Send message from host to firmware
+ * @client_data:	Client data instance
+ * @out_msg:		Message buffer to be sent to firmware
+ * @out_size:		Size of out going message
+ * @in_msg:		Message buffer where the incoming data copied.
+ *			This buffer is allocated by calling
+ * @in_size:		Max size of incoming message
+ *
+ * Return: Number of bytes copied in the in_msg on success, negative
+ * error code on failure.
+ */
+static int ish_send(struct ishtp_cl_data *client_data,
+		    u8 *out_msg, size_t out_size,
+		    u8 *in_msg, size_t in_size)
+{
+	int rv;
+	struct header *out_hdr = (struct header *)out_msg;
+	struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl;
+
+	dev_dbg(cl_data_to_dev(client_data),
+		"%s: channel=%02u status=%02u\n",
+		__func__, out_hdr->channel, out_hdr->status);
+
+	/* Setup for incoming response */
+	client_data->response.data = in_msg;
+	client_data->response.max_size = in_size;
+	client_data->response.error = 0;
+	client_data->response.received = false;
+
+	rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
+	if (rv) {
+		dev_err(cl_data_to_dev(client_data),
+			"ishtp_cl_send error %d\n", rv);
+		return rv;
+	}
+
+	wait_event_interruptible_timeout(client_data->response.wait_queue,
+					 client_data->response.received,
+					 ISHTP_SEND_TIMEOUT);
+	if (!client_data->response.received) {
+		dev_err(cl_data_to_dev(client_data),
+			"Timed out for response to host message\n");
+		return -ETIMEDOUT;
+	}
+
+	if (client_data->response.error < 0)
+		return client_data->response.error;
+
+	return client_data->response.size;
+}
+
+/**
+ * process_recv() -	Received and parse incoming packet
+ * @cros_ish_cl:	Client instance to get stats
+ * @rb_in_proc:		Host interface message buffer
+ *
+ * Parse the incoming packet. If it is a response packet then it will
+ * update per instance flags and wake up the caller waiting to for the
+ * response. If it is an event packet then it will schedule event work.
+ */
+static void process_recv(struct ishtp_cl *cros_ish_cl,
+			 struct ishtp_cl_rb *rb_in_proc)
+{
+	size_t data_len = rb_in_proc->buf_idx;
+	struct ishtp_cl_data *client_data =
+		ishtp_get_client_data(cros_ish_cl);
+	struct device *dev = cl_data_to_dev(client_data);
+	struct cros_ish_in_msg *in_msg =
+		(struct cros_ish_in_msg *)rb_in_proc->buffer.data;
+
+	/* Proceed only if reset or init is not in progress */
+	if (!down_read_trylock(&init_lock)) {
+		/* Free the buffer */
+		ishtp_cl_io_rb_recycle(rb_in_proc);
+		dev_warn(dev,
+			 "Host is not ready to receive incoming messages\n");
+		return;
+	}
+
+	/*
+	 * All firmware messages contain a header. Check the buffer size
+	 * before accessing elements inside.
+	 */
+	if (!rb_in_proc->buffer.data) {
+		dev_warn(dev, "rb_in_proc->buffer.data returned null");
+		client_data->response.error = -EBADMSG;
+		goto end_error;
+	}
+
+	if (data_len < sizeof(struct header)) {
+		dev_err(dev, "data size %zu is less than header %zu\n",
+			data_len, sizeof(struct header));
+		client_data->response.error = -EMSGSIZE;
+		goto end_error;
+	}
+
+	dev_dbg(dev, "channel=%02u status=%02u\n",
+		in_msg->hdr.channel, in_msg->hdr.status);
+
+	switch (in_msg->hdr.channel) {
+	case CROS_EC_COMMAND:
+		/* Sanity check */
+		if (!client_data->response.data) {
+			dev_err(dev,
+				"Receiving buffer is null. Should be allocated by calling function\n");
+			client_data->response.error = -EINVAL;
+			goto error_wake_up;
+		}
+
+		if (client_data->response.received) {
+			dev_err(dev,
+				"Previous firmware message not yet processed\n");
+			client_data->response.error = -EINVAL;
+			goto error_wake_up;
+		}
+
+		if (data_len > client_data->response.max_size) {
+			dev_err(dev,
+				"Received buffer size %zu is larger than allocated buffer %zu\n",
+				data_len, client_data->response.max_size);
+			client_data->response.error = -EMSGSIZE;
+			goto error_wake_up;
+		}
+
+		if (in_msg->hdr.status) {
+			dev_err(dev, "firmware returned status %d\n",
+				in_msg->hdr.status);
+			client_data->response.error = -EIO;
+			goto error_wake_up;
+		}
+
+		/* Update the actual received buffer size */
+		client_data->response.size = data_len;
+
+		/*
+		 * Copy the buffer received in firmware response for the
+		 * calling thread.
+		 */
+		memcpy(client_data->response.data,
+		       rb_in_proc->buffer.data, data_len);
+
+		/* Set flag before waking up the caller */
+		client_data->response.received = true;
+error_wake_up:
+		/* Wake the calling thread */
+		wake_up_interruptible(&client_data->response.wait_queue);
+
+		break;
+
+	case CROS_MKBP_EVENT:
+		/* The event system doesn't send any data in buffer */
+		schedule_work(&client_data->work_ec_evt);
+
+		break;
+
+	default:
+		dev_err(dev, "Invalid channel=%02d\n", in_msg->hdr.channel);
+	}
+
+end_error:
+	/* Free the buffer */
+	ishtp_cl_io_rb_recycle(rb_in_proc);
+
+	up_read(&init_lock);
+}
+
+/**
+ * ish_event_cb() - bus driver callback for incoming message
+ * @cl_device:		ISHTP client device for which this message is
+ *			targeted.
+ *
+ * Remove the packet from the list and process the message by calling
+ * process_recv.
+ */
+static void ish_event_cb(struct ishtp_cl_device *cl_device)
+{
+	struct ishtp_cl_rb *rb_in_proc;
+	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
+
+	while ((rb_in_proc = ishtp_cl_rx_get_rb(cros_ish_cl)) != NULL) {
+		/* Decide what to do with received data */
+		process_recv(cros_ish_cl, rb_in_proc);
+	}
+}
+
+/**
+ * cros_ish_init() - Init function for ISHTP client
+ * @cros_ish_cl:	ISHTP client instance
+ *
+ * This function complete the initializtion of the client.
+ *
+ * Return: 0 for success, negative error code for failure.
+ */
+static int cros_ish_init(struct ishtp_cl *cros_ish_cl)
+{
+	int rv;
+	struct ishtp_device *dev;
+	struct ishtp_fw_client *fw_client;
+	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
+
+	rv = ishtp_cl_link(cros_ish_cl);
+	if (rv) {
+		dev_err(cl_data_to_dev(client_data),
+			"ishtp_cl_link failed\n");
+		return rv;
+	}
+
+	dev = ishtp_get_ishtp_device(cros_ish_cl);
+
+	/* Connect to firmware client */
+	ishtp_set_tx_ring_size(cros_ish_cl, CROS_ISH_CL_TX_RING_SIZE);
+	ishtp_set_rx_ring_size(cros_ish_cl, CROS_ISH_CL_RX_RING_SIZE);
+
+	fw_client = ishtp_fw_cl_get_client(dev, &cros_ish_guid);
+	if (!fw_client) {
+		dev_err(cl_data_to_dev(client_data),
+			"ish client uuid not found\n");
+		rv = -ENOENT;
+		goto err_cl_unlink;
+	}
+
+	ishtp_cl_set_fw_client_id(cros_ish_cl,
+				  ishtp_get_fw_client_id(fw_client));
+	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_CONNECTING);
+
+	rv = ishtp_cl_connect(cros_ish_cl);
+	if (rv) {
+		dev_err(cl_data_to_dev(client_data),
+			"client connect fail\n");
+		goto err_cl_unlink;
+	}
+
+	ishtp_register_event_cb(client_data->cl_device, ish_event_cb);
+	return 0;
+
+err_cl_unlink:
+	ishtp_cl_unlink(cros_ish_cl);
+	return rv;
+}
+
+/**
+ * cros_ish_deinit() - Deinit function for ISHTP client
+ * @cros_ish_cl:	ISHTP client instance
+ *
+ * Unlink and free cros_ec client
+ */
+static void cros_ish_deinit(struct ishtp_cl *cros_ish_cl)
+{
+	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
+	ishtp_cl_disconnect(cros_ish_cl);
+	ishtp_cl_unlink(cros_ish_cl);
+	ishtp_cl_flush_queues(cros_ish_cl);
+
+	/* Disband and free all Tx and Rx client-level rings */
+	ishtp_cl_free(cros_ish_cl);
+}
+
+/**
+ * prepare_cros_ec_rx() - Check & prepare receive buffer
+ * @in_msg:		Incoming message buffer
+ * @cros_ec_command	cros_ec command used to send & receive data
+ *
+ * Check the received buffer. Convert to cros_ec_command format.
+ */
+static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
+			      const struct cros_ish_in_msg *in_msg,
+			      struct cros_ec_command *msg)
+{
+	u8 sum = 0;
+	int i, rv, offset;
+
+	/* Check response error code */
+	msg->result = in_msg->ec_response.result;
+	rv = cros_ec_check_result(ec_dev, msg);
+	if (rv < 0)
+		return rv;
+
+	if (in_msg->ec_response.data_len > msg->insize) {
+		dev_err(ec_dev->dev, "Packet too long (%d bytes, expected %d)",
+			in_msg->ec_response.data_len, msg->insize);
+		return -ENOSPC;
+	}
+
+	/* Copy response packet payload and compute checksum */
+	for (i = 0; i < sizeof(struct ec_host_response); i++)
+		sum += ((u8 *)in_msg)[IN_MSG_EC_RESPONSE_PREAMBLE + i];
+
+	offset = sizeof(struct cros_ish_in_msg);
+	for (i = 0; i < in_msg->ec_response.data_len; i++)
+		sum += msg->data[i] = ((u8 *)in_msg)[offset + i];
+
+	if (sum) {
+		dev_dbg(ec_dev->dev, "Bad received packet checksum %d\n", sum);
+		return -EBADMSG;
+	}
+
+	return 0;
+}
+
+static int cros_ec_pkt_xfer_ish(struct cros_ec_device *ec_dev,
+				struct cros_ec_command *msg)
+{
+	int rv;
+	struct ishtp_cl *cros_ish_cl = ec_dev->priv;
+	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
+	struct device *dev = cl_data_to_dev(client_data);
+	struct cros_ish_in_msg *in_msg = (struct cros_ish_in_msg *)ec_dev->din;
+	struct cros_ish_out_msg *out_msg =
+		(struct cros_ish_out_msg *)ec_dev->dout;
+	size_t in_size = sizeof(struct cros_ish_in_msg) + msg->insize;
+	size_t out_size = sizeof(struct cros_ish_out_msg) + msg->outsize;
+
+	/* Proceed only if reset-init is not in progress */
+	if (!down_read_trylock(&init_lock)) {
+		dev_warn(dev,
+			 "Host is not ready to send messages to ISH. Try again\n");
+		return -EAGAIN;
+	}
+
+	/* Sanity checks */
+	if (in_size > ec_dev->din_size) {
+		dev_err(dev,
+			"Incoming payload size %zu is too large for ec_dev->din_size %d\n",
+			in_size, ec_dev->din_size);
+		return -EMSGSIZE;
+	}
+
+	if (out_size > ec_dev->dout_size) {
+		dev_err(dev,
+			"Outgoing payload size %zu is too large for ec_dev->dout_size %d\n",
+			out_size, ec_dev->dout_size);
+		return -EMSGSIZE;
+	}
+
+	/* Prepare the package to be sent over ISH TP */
+	out_msg->hdr.channel = CROS_EC_COMMAND;
+	out_msg->hdr.status = 0;
+
+	ec_dev->dout += OUT_MSG_EC_REQUEST_PREAMBLE;
+	cros_ec_prepare_tx(ec_dev, msg);
+	ec_dev->dout -= OUT_MSG_EC_REQUEST_PREAMBLE;
+
+	dev_dbg(dev,
+		"out_msg: struct_ver=0x%x checksum=0x%x command=0x%x command_ver=0x%x data_len=0x%x\n",
+		out_msg->ec_request.struct_version,
+		out_msg->ec_request.checksum,
+		out_msg->ec_request.command,
+		out_msg->ec_request.command_version,
+		out_msg->ec_request.data_len);
+
+	/* Send command to ISH EC firmware and read response */
+	rv = ish_send(client_data,
+		      (u8 *)out_msg, out_size,
+		      (u8 *)in_msg, in_size);
+	if (rv < 0)
+		goto end_error;
+
+	rv = prepare_cros_ec_rx(ec_dev, in_msg, msg);
+	if (rv)
+		goto end_error;
+
+	rv = in_msg->ec_response.data_len;
+
+	dev_dbg(dev,
+		"in_msg: struct_ver=0x%x checksum=0x%x result=0x%x data_len=0x%x\n",
+		in_msg->ec_response.struct_version,
+		in_msg->ec_response.checksum,
+		in_msg->ec_response.result,
+		in_msg->ec_response.data_len);
+
+end_error:
+	if (msg->command == EC_CMD_REBOOT_EC)
+		msleep(EC_REBOOT_DELAY_MS);
+
+	up_read(&init_lock);
+
+	return rv;
+}
+
+static int cros_ec_dev_init(struct ishtp_cl_data *client_data)
+{
+	struct cros_ec_device *ec_dev;
+	struct device *dev = cl_data_to_dev(client_data);
+
+	ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
+	if (!ec_dev)
+		return -ENOMEM;
+
+	client_data->ec_dev = ec_dev;
+	dev->driver_data = ec_dev;
+
+	ec_dev->dev = dev;
+	ec_dev->priv = client_data->cros_ish_cl;
+	ec_dev->cmd_xfer = NULL;
+	ec_dev->pkt_xfer = cros_ec_pkt_xfer_ish;
+	ec_dev->phys_name = dev_name(dev);
+	ec_dev->din_size = sizeof(struct cros_ish_in_msg) +
+			   sizeof(struct ec_response_get_protocol_info);
+	ec_dev->dout_size = sizeof(struct cros_ish_out_msg);
+
+	return cros_ec_register(ec_dev);
+}
+
+static void reset_handler(struct work_struct *work)
+{
+	int rv;
+	struct device *dev;
+	struct ishtp_cl *cros_ish_cl;
+	struct ishtp_cl_device *cl_device;
+	struct ishtp_cl_data *client_data =
+		container_of(work, struct ishtp_cl_data, work_ishtp_reset);
+
+	/* Lock for reset to complete */
+	down_write(&init_lock);
+
+	cros_ish_cl = client_data->cros_ish_cl;
+	cl_device = client_data->cl_device;
+
+	/* Unlink, flush queues & start again */
+	ishtp_cl_unlink(cros_ish_cl);
+	ishtp_cl_flush_queues(cros_ish_cl);
+	ishtp_cl_free(cros_ish_cl);
+
+	cros_ish_cl = ishtp_cl_allocate(cl_device);
+	if (!cros_ish_cl) {
+		up_write(&init_lock);
+		return;
+	}
+
+	ishtp_set_drvdata(cl_device, cros_ish_cl);
+	ishtp_set_client_data(cros_ish_cl, client_data);
+	client_data->cros_ish_cl = cros_ish_cl;
+
+	rv = cros_ish_init(cros_ish_cl);
+	if (rv) {
+		ishtp_cl_free(cros_ish_cl);
+		dev_err(cl_data_to_dev(client_data), "Reset Failed\n");
+		up_write(&init_lock);
+		return;
+	}
+
+	/* Refresh ec_dev device pointers */
+	client_data->ec_dev->priv = client_data->cros_ish_cl;
+	dev = cl_data_to_dev(client_data);
+	dev->driver_data = client_data->ec_dev;
+
+	dev_info(cl_data_to_dev(client_data), "Chrome EC ISH reset done\n");
+
+	up_write(&init_lock);
+}
+
+/**
+ * cros_ec_ishtp_probe() - ISHTP client driver probe callback
+ * @cl_device:		ISHTP client device instance
+ *
+ * Return: 0 for success, negative error code for failure.
+ */
+static int cros_ec_ishtp_probe(struct ishtp_cl_device *cl_device)
+{
+	int rv;
+	struct ishtp_cl *cros_ish_cl;
+	struct ishtp_cl_data *client_data =
+		devm_kzalloc(ishtp_device(cl_device),
+			     sizeof(*client_data), GFP_KERNEL);
+	if (!client_data)
+		return -ENOMEM;
+
+	/* Lock for initialization to complete */
+	down_write(&init_lock);
+
+	cros_ish_cl = ishtp_cl_allocate(cl_device);
+	if (!cros_ish_cl) {
+		rv = -ENOMEM;
+		goto end_ishtp_cl_alloc_error;
+	}
+
+	ishtp_set_drvdata(cl_device, cros_ish_cl);
+	ishtp_set_client_data(cros_ish_cl, client_data);
+	client_data->cros_ish_cl = cros_ish_cl;
+	client_data->cl_device = cl_device;
+
+	init_waitqueue_head(&client_data->response.wait_queue);
+
+	INIT_WORK(&client_data->work_ishtp_reset,
+		  reset_handler);
+	INIT_WORK(&client_data->work_ec_evt,
+		  ish_evt_handler);
+
+	rv = cros_ish_init(cros_ish_cl);
+	if (rv)
+		goto end_ishtp_cl_init_error;
+
+	ishtp_get_device(cl_device);
+
+	up_write(&init_lock);
+
+	/* Register croc_ec_dev mfd */
+	rv = cros_ec_dev_init(client_data);
+	if (rv)
+		goto end_cros_ec_dev_init_error;
+
+	return 0;
+
+end_cros_ec_dev_init_error:
+	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
+	ishtp_cl_disconnect(cros_ish_cl);
+	ishtp_cl_unlink(cros_ish_cl);
+	ishtp_cl_flush_queues(cros_ish_cl);
+	ishtp_put_device(cl_device);
+end_ishtp_cl_init_error:
+	ishtp_cl_free(cros_ish_cl);
+end_ishtp_cl_alloc_error:
+	up_write(&init_lock);
+	return rv;
+}
+
+/**
+ * cros_ec_ishtp_remove() - ISHTP client driver remove callback
+ * @cl_device:		ISHTP client device instance
+ *
+ * Return: 0
+ */
+static int cros_ec_ishtp_remove(struct ishtp_cl_device *cl_device)
+{
+	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
+	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
+
+	cancel_work_sync(&client_data->work_ishtp_reset);
+	cancel_work_sync(&client_data->work_ec_evt);
+	cros_ish_deinit(cros_ish_cl);
+	ishtp_put_device(cl_device);
+
+	return 0;
+}
+
+/**
+ * cros_ec_ishtp_reset() - ISHTP client driver reset callback
+ * @cl_device:		ISHTP client device instance
+ *
+ * Return: 0
+ */
+static int cros_ec_ishtp_reset(struct ishtp_cl_device *cl_device)
+{
+	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
+	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
+
+	schedule_work(&client_data->work_ishtp_reset);
+
+	return 0;
+}
+
+/**
+ * cros_ec_ishtp_suspend() - ISHTP client driver suspend callback
+ * @device:	device instance
+ *
+ * Return: 0 for success, negative error code for failure.
+ */
+static int __maybe_unused cros_ec_ishtp_suspend(struct device *device)
+{
+	struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
+	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
+	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
+
+	return cros_ec_suspend(client_data->ec_dev);
+}
+
+/**
+ * cros_ec_ishtp_resume() - ISHTP client driver resume callback
+ * @device:	device instance
+ *
+ * Return: 0 for success, negative error code for failure.
+ */
+static int __maybe_unused cros_ec_ishtp_resume(struct device *device)
+{
+	struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
+	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
+	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
+
+	return cros_ec_resume(client_data->ec_dev);
+}
+
+static SIMPLE_DEV_PM_OPS(cros_ec_ishtp_pm_ops, cros_ec_ishtp_suspend,
+			 cros_ec_ishtp_resume);
+
+static struct ishtp_cl_driver	cros_ec_ishtp_driver = {
+	.name = "cros_ec_ishtp",
+	.guid = &cros_ish_guid,
+	.probe = cros_ec_ishtp_probe,
+	.remove = cros_ec_ishtp_remove,
+	.reset = cros_ec_ishtp_reset,
+	.driver = {
+		.pm = &cros_ec_ishtp_pm_ops,
+	},
+};
+
+static int __init cros_ec_ishtp_mod_init(void)
+{
+	return ishtp_cl_driver_register(&cros_ec_ishtp_driver, THIS_MODULE);
+}
+
+static void __exit cros_ec_ishtp_mod_exit(void)
+{
+	ishtp_cl_driver_unregister(&cros_ec_ishtp_driver);
+}
+
+module_init(cros_ec_ishtp_mod_init);
+module_exit(cros_ec_ishtp_mod_exit);
+
+MODULE_DESCRIPTION("ChromeOS EC ISHTP Client Driver");
+MODULE_AUTHOR("Rushikesh S Kadam <rushikesh.s.kadam@intel.com>");
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("ishtp:*");
-- 
1.9.1

Re: [PATCH v3] platform: chrome: Add ChromeOS EC ISHTP driver

[Jett Rink]

Reviewed-by: Jett Rink <jettrink@chromium.org>
Tested-by: Jett Rink <jettrink@chromium.org>


On Sun, Apr 7, 2019 at 6:10 AM Rushikesh S Kadam
<rushikesh.s.kadam@intel.com> wrote:
>
> This driver implements a slim layer to enable the ChromeOS
> EC kernel stack (cros_ec) to communicate with ChromeOS EC
> firmware running on the Intel Integrated Sensor Hub (ISH).
>
> The driver registers a ChromeOS EC MFD device to connect
> with cros_ec kernel stack (upper layer), and it registers a
> client with the ISH Transport Protocol bus (lower layer) to
> talk with the ISH firwmare. See description of the ISHTP
> protocol at Documentation/hid/intel-ish-hid.txt
>
> Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
> ---
>
> v3
>  - Made several changes to improve code readability. Replaced
>    multiple cl_data_to_dev(client_data) with dev variable. Use
>    reverse Xmas tree for variable defintion where it made sense.
>    Dropped few debug prints. Add docstring for function
>    prepare_cros_ec_rx().
>  - Fix code in function prepare_cros_ec_rx() under label
>    end_cros_ec_dev_init_error.
>  - Recycle buffer in process_recv() on failing to obtain the
>    semaphore.
>  - Increase ISHTP TX/RX ring buffer size to 8.
>  - Alphabetically ordered CROS_EC_ISHTP entries in Makefile and
>    Kconfig.
>  - Updated commit message.
>
> v2
>  - Dropped unused "reset" parameter in function cros_ec_init()
>  - Change driver name to cros_ec_ishtp to be consistent with other
>    references in the code.
>  - Fixed a few typos.
>
> v1
>  - Initial version
>
>  drivers/platform/chrome/Kconfig         |  13 +
>  drivers/platform/chrome/Makefile        |   1 +
>  drivers/platform/chrome/cros_ec_ishtp.c | 765 ++++++++++++++++++++++++++++++++
>  3 files changed, 779 insertions(+)
>  create mode 100644 drivers/platform/chrome/cros_ec_ishtp.c
>
> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> index 16b1615..5848179 100644
> --- a/drivers/platform/chrome/Kconfig
> +++ b/drivers/platform/chrome/Kconfig
> @@ -62,6 +62,19 @@ config CROS_EC_I2C
>           a checksum. Failing accesses will be retried three times to
>           improve reliability.
>
> +config CROS_EC_ISHTP
> +       tristate "ChromeOS Embedded Controller (ISHTP)"
> +       depends on MFD_CROS_EC
> +       depends on INTEL_ISH_HID
> +       help
> +         If you say Y here, you get support for talking to the ChromeOS EC
> +         firmware running on Intel Integrated Sensor Hub (ISH), using the
> +         ISH Transport protocol (ISH-TP). This uses a simple byte-level
> +         protocol with a checksum.
> +
> +         To compile this driver as a module, choose M here: the
> +         module will be called cros_ec_ishtp.
> +
>  config CROS_EC_SPI
>         tristate "ChromeOS Embedded Controller (SPI)"
>         depends on MFD_CROS_EC && SPI
> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> index cd591bf..4efe102 100644
> --- a/drivers/platform/chrome/Makefile
> +++ b/drivers/platform/chrome/Makefile
> @@ -7,6 +7,7 @@ cros_ec_ctl-objs                        := cros_ec_sysfs.o cros_ec_lightbar.o \
>                                            cros_ec_vbc.o cros_ec_debugfs.o
>  obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
> +obj-$(CONFIG_CROS_EC_ISHTP)            += cros_ec_ishtp.o
>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
>  cros_ec_lpcs-objs                      := cros_ec_lpc.o cros_ec_lpc_reg.o
>  cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC) += cros_ec_lpc_mec.o
> diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c
> new file mode 100644
> index 0000000..b1d19c4
> --- /dev/null
> +++ b/drivers/platform/chrome/cros_ec_ishtp.c
> @@ -0,0 +1,765 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ISHTP client driver for talking to the Chrome OS EC firmware running
> + * on Intel Integrated Sensor Hub (ISH) using the ISH Transport protocol
> + * (ISH-TP).
> + *
> + * Copyright (c) 2019, Intel Corporation.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/cros_ec.h>
> +#include <linux/mfd/cros_ec_commands.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/intel-ish-client-if.h>
> +
> +/*
> + * ISH TX/RX ring buffer pool size
> + *
> + * The AP->ISH messages and corresponding ISH->AP responses are
> + * serialized. We need 1 TX and 1 RX buffer for these.
> + *
> + * The MKBP ISH->AP events are serialized. We need one additional RX
> + * buffer for them.
> + */
> +#define CROS_ISH_CL_TX_RING_SIZE               8
> +#define CROS_ISH_CL_RX_RING_SIZE               8
> +
> +/* ISH CrOS EC Host Commands */
> +enum cros_ec_ish_channel {
> +       CROS_EC_COMMAND = 1,                    /* AP->ISH message */
> +       CROS_MKBP_EVENT = 2,                    /* ISH->AP events */
> +};
> +
> +/*
> + * ISH firmware timeout for 1 message send failure is 1Hz, and the
> + * firmware will retry 2 times, so 3Hz is used for timeout.
> + */
> +#define ISHTP_SEND_TIMEOUT                     (3 * HZ)
> +
> +/* ISH Transport CrOS EC ISH client unique GUID */
> +static const guid_t cros_ish_guid =
> +       GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
> +                 0xb0, 0xd8, 0x9e, 0x7c, 0xda, 0xe0, 0xd6, 0xa0);
> +
> +struct header {
> +       u8 channel;
> +       u8 status;
> +       u8 reserved[2];
> +} __packed;
> +
> +struct cros_ish_out_msg {
> +       struct header hdr;
> +       struct ec_host_request ec_request;
> +} __packed;
> +
> +struct cros_ish_in_msg {
> +       struct header hdr;
> +       struct ec_host_response ec_response;
> +} __packed;
> +
> +#define IN_MSG_EC_RESPONSE_PREAMBLE                                    \
> +       offsetof(struct cros_ish_in_msg, ec_response)
> +
> +#define OUT_MSG_EC_REQUEST_PREAMBLE                                    \
> +       offsetof(struct cros_ish_out_msg, ec_request)
> +
> +#define cl_data_to_dev(client_data) ishtp_device((client_data)->cl_device)
> +
> +/*
> + * The Read-Write Semaphore is used to prevent message TX or RX while
> + * the ishtp client is being initialized or undergoing reset.
> + *
> + * The readers are the kernel function calls responsible for IA->ISH
> + * and ISH->AP messaging.
> + *
> + * The writers are .reset() and .probe() function.
> + */
> +DECLARE_RWSEM(init_lock);
> +
> +/**
> + * struct response_info - Encapsulate firmware response related
> + *                     information for passing between function
> + *                     ish_send() and process_recv() callback.
> + * @data:              Copy the data received from firmware here.
> + * @max_size:          Max size allocated for the @data buffer. If the
> + *                     received data exceeds this value, we log an
> + *                     error.
> + * @size:              Actual size of data received from firmware.
> + * @error:             0 for success, negative error code for a
> + *                     failure in function process_recv().
> + * @received:          Set to true on receiving a valid firmware
> + *                     response to host command
> + * @wait_queue:                Wait queue for Host firmware loading where the
> + *                     client sends message to ISH firmware and waits
> + *                     for response
> + */
> +struct response_info {
> +       void *data;
> +       size_t max_size;
> +       size_t size;
> +       int error;
> +       bool received;
> +       wait_queue_head_t wait_queue;
> +};
> +
> +/**
> + * struct ishtp_cl_data - Encapsulate per ISH TP Client.
> + * @cros_ish_cl:       ISHTP firmware client instance.
> + * @cl_device:         ISHTP client device instance.
> + * @response:          Firmware response information for passing
> + *                     between function ish_send() and process_recv()
> + *                     callback.
> + * @work_ishtp_reset:  Work queue reset handling.
> + * @work_ec_evt:       Work queue for EC events.
> + * @ec_dev:            CrOS EC MFD device.
> + *
> + * This structure is used to store per client data.
> + */
> +struct ishtp_cl_data {
> +       struct ishtp_cl *cros_ish_cl;
> +       struct ishtp_cl_device *cl_device;
> +
> +       /*
> +        * Used for passing firmware response information between
> +        * ish_send() and process_recv() callback.
> +        */
> +       struct response_info response;
> +
> +       struct work_struct work_ishtp_reset;
> +       struct work_struct work_ec_evt;
> +       struct cros_ec_device *ec_dev;
> +};
> +
> +/**
> + * ish_evt_handler - ISH to AP event handler
> + * @work:              Work struct
> + */
> +static void ish_evt_handler(struct work_struct *work)
> +{
> +       struct ishtp_cl_data *client_data =
> +               container_of(work, struct ishtp_cl_data, work_ec_evt);
> +       struct cros_ec_device *ec_dev = client_data->ec_dev;
> +
> +       if (cros_ec_get_next_event(ec_dev, NULL) > 0) {
> +               blocking_notifier_call_chain(&ec_dev->event_notifier,
> +                                            0, ec_dev);
> +       }
> +}
> +
> +/**
> + * ish_send() - Send message from host to firmware
> + * @client_data:       Client data instance
> + * @out_msg:           Message buffer to be sent to firmware
> + * @out_size:          Size of out going message
> + * @in_msg:            Message buffer where the incoming data copied.
> + *                     This buffer is allocated by calling
> + * @in_size:           Max size of incoming message
> + *
> + * Return: Number of bytes copied in the in_msg on success, negative
> + * error code on failure.
> + */
> +static int ish_send(struct ishtp_cl_data *client_data,
> +                   u8 *out_msg, size_t out_size,
> +                   u8 *in_msg, size_t in_size)
> +{
> +       int rv;
> +       struct header *out_hdr = (struct header *)out_msg;
> +       struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl;
> +
> +       dev_dbg(cl_data_to_dev(client_data),
> +               "%s: channel=%02u status=%02u\n",
> +               __func__, out_hdr->channel, out_hdr->status);
> +
> +       /* Setup for incoming response */
> +       client_data->response.data = in_msg;
> +       client_data->response.max_size = in_size;
> +       client_data->response.error = 0;
> +       client_data->response.received = false;
> +
> +       rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
> +       if (rv) {
> +               dev_err(cl_data_to_dev(client_data),
> +                       "ishtp_cl_send error %d\n", rv);
> +               return rv;
> +       }
> +
> +       wait_event_interruptible_timeout(client_data->response.wait_queue,
> +                                        client_data->response.received,
> +                                        ISHTP_SEND_TIMEOUT);
> +       if (!client_data->response.received) {
> +               dev_err(cl_data_to_dev(client_data),
> +                       "Timed out for response to host message\n");
> +               return -ETIMEDOUT;
> +       }
> +
> +       if (client_data->response.error < 0)
> +               return client_data->response.error;
> +
> +       return client_data->response.size;
> +}
> +
> +/**
> + * process_recv() -    Received and parse incoming packet
> + * @cros_ish_cl:       Client instance to get stats
> + * @rb_in_proc:                Host interface message buffer
> + *
> + * Parse the incoming packet. If it is a response packet then it will
> + * update per instance flags and wake up the caller waiting to for the
> + * response. If it is an event packet then it will schedule event work.
> + */
> +static void process_recv(struct ishtp_cl *cros_ish_cl,
> +                        struct ishtp_cl_rb *rb_in_proc)
> +{
> +       size_t data_len = rb_in_proc->buf_idx;
> +       struct ishtp_cl_data *client_data =
> +               ishtp_get_client_data(cros_ish_cl);
> +       struct device *dev = cl_data_to_dev(client_data);
> +       struct cros_ish_in_msg *in_msg =
> +               (struct cros_ish_in_msg *)rb_in_proc->buffer.data;
> +
> +       /* Proceed only if reset or init is not in progress */
> +       if (!down_read_trylock(&init_lock)) {
> +               /* Free the buffer */
> +               ishtp_cl_io_rb_recycle(rb_in_proc);
> +               dev_warn(dev,
> +                        "Host is not ready to receive incoming messages\n");
> +               return;
> +       }
> +
> +       /*
> +        * All firmware messages contain a header. Check the buffer size
> +        * before accessing elements inside.
> +        */
> +       if (!rb_in_proc->buffer.data) {
> +               dev_warn(dev, "rb_in_proc->buffer.data returned null");
> +               client_data->response.error = -EBADMSG;
> +               goto end_error;
> +       }
> +
> +       if (data_len < sizeof(struct header)) {
> +               dev_err(dev, "data size %zu is less than header %zu\n",
> +                       data_len, sizeof(struct header));
> +               client_data->response.error = -EMSGSIZE;
> +               goto end_error;
> +       }
> +
> +       dev_dbg(dev, "channel=%02u status=%02u\n",
> +               in_msg->hdr.channel, in_msg->hdr.status);
> +
> +       switch (in_msg->hdr.channel) {
> +       case CROS_EC_COMMAND:
> +               /* Sanity check */
> +               if (!client_data->response.data) {
> +                       dev_err(dev,
> +                               "Receiving buffer is null. Should be allocated by calling function\n");
> +                       client_data->response.error = -EINVAL;
> +                       goto error_wake_up;
> +               }
> +
> +               if (client_data->response.received) {
> +                       dev_err(dev,
> +                               "Previous firmware message not yet processed\n");
> +                       client_data->response.error = -EINVAL;
> +                       goto error_wake_up;
> +               }
> +
> +               if (data_len > client_data->response.max_size) {
> +                       dev_err(dev,
> +                               "Received buffer size %zu is larger than allocated buffer %zu\n",
> +                               data_len, client_data->response.max_size);
> +                       client_data->response.error = -EMSGSIZE;
> +                       goto error_wake_up;
> +               }
> +
> +               if (in_msg->hdr.status) {
> +                       dev_err(dev, "firmware returned status %d\n",
> +                               in_msg->hdr.status);
> +                       client_data->response.error = -EIO;
> +                       goto error_wake_up;
> +               }
> +
> +               /* Update the actual received buffer size */
> +               client_data->response.size = data_len;
> +
> +               /*
> +                * Copy the buffer received in firmware response for the
> +                * calling thread.
> +                */
> +               memcpy(client_data->response.data,
> +                      rb_in_proc->buffer.data, data_len);
> +
> +               /* Set flag before waking up the caller */
> +               client_data->response.received = true;
> +error_wake_up:
> +               /* Wake the calling thread */
> +               wake_up_interruptible(&client_data->response.wait_queue);
> +
> +               break;
> +
> +       case CROS_MKBP_EVENT:
> +               /* The event system doesn't send any data in buffer */
> +               schedule_work(&client_data->work_ec_evt);
> +
> +               break;
> +
> +       default:
> +               dev_err(dev, "Invalid channel=%02d\n", in_msg->hdr.channel);
> +       }
> +
> +end_error:
> +       /* Free the buffer */
> +       ishtp_cl_io_rb_recycle(rb_in_proc);
> +
> +       up_read(&init_lock);
> +}
> +
> +/**
> + * ish_event_cb() - bus driver callback for incoming message
> + * @cl_device:         ISHTP client device for which this message is
> + *                     targeted.
> + *
> + * Remove the packet from the list and process the message by calling
> + * process_recv.
> + */
> +static void ish_event_cb(struct ishtp_cl_device *cl_device)
> +{
> +       struct ishtp_cl_rb *rb_in_proc;
> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> +
> +       while ((rb_in_proc = ishtp_cl_rx_get_rb(cros_ish_cl)) != NULL) {
> +               /* Decide what to do with received data */
> +               process_recv(cros_ish_cl, rb_in_proc);
> +       }
> +}
> +
> +/**
> + * cros_ish_init() - Init function for ISHTP client
> + * @cros_ish_cl:       ISHTP client instance
> + *
> + * This function complete the initializtion of the client.
> + *
> + * Return: 0 for success, negative error code for failure.
> + */
> +static int cros_ish_init(struct ishtp_cl *cros_ish_cl)
> +{
> +       int rv;
> +       struct ishtp_device *dev;
> +       struct ishtp_fw_client *fw_client;
> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +       rv = ishtp_cl_link(cros_ish_cl);
> +       if (rv) {
> +               dev_err(cl_data_to_dev(client_data),
> +                       "ishtp_cl_link failed\n");
> +               return rv;
> +       }
> +
> +       dev = ishtp_get_ishtp_device(cros_ish_cl);
> +
> +       /* Connect to firmware client */
> +       ishtp_set_tx_ring_size(cros_ish_cl, CROS_ISH_CL_TX_RING_SIZE);
> +       ishtp_set_rx_ring_size(cros_ish_cl, CROS_ISH_CL_RX_RING_SIZE);
> +
> +       fw_client = ishtp_fw_cl_get_client(dev, &cros_ish_guid);
> +       if (!fw_client) {
> +               dev_err(cl_data_to_dev(client_data),
> +                       "ish client uuid not found\n");
> +               rv = -ENOENT;
> +               goto err_cl_unlink;
> +       }
> +
> +       ishtp_cl_set_fw_client_id(cros_ish_cl,
> +                                 ishtp_get_fw_client_id(fw_client));
> +       ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_CONNECTING);
> +
> +       rv = ishtp_cl_connect(cros_ish_cl);
> +       if (rv) {
> +               dev_err(cl_data_to_dev(client_data),
> +                       "client connect fail\n");
> +               goto err_cl_unlink;
> +       }
> +
> +       ishtp_register_event_cb(client_data->cl_device, ish_event_cb);
> +       return 0;
> +
> +err_cl_unlink:
> +       ishtp_cl_unlink(cros_ish_cl);
> +       return rv;
> +}
> +
> +/**
> + * cros_ish_deinit() - Deinit function for ISHTP client
> + * @cros_ish_cl:       ISHTP client instance
> + *
> + * Unlink and free cros_ec client
> + */
> +static void cros_ish_deinit(struct ishtp_cl *cros_ish_cl)
> +{
> +       ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
> +       ishtp_cl_disconnect(cros_ish_cl);
> +       ishtp_cl_unlink(cros_ish_cl);
> +       ishtp_cl_flush_queues(cros_ish_cl);
> +
> +       /* Disband and free all Tx and Rx client-level rings */
> +       ishtp_cl_free(cros_ish_cl);
> +}
> +
> +/**
> + * prepare_cros_ec_rx() - Check & prepare receive buffer
> + * @in_msg:            Incoming message buffer
> + * @cros_ec_command    cros_ec command used to send & receive data
> + *
> + * Check the received buffer. Convert to cros_ec_command format.
> + */
> +static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
> +                             const struct cros_ish_in_msg *in_msg,
> +                             struct cros_ec_command *msg)
> +{
> +       u8 sum = 0;
> +       int i, rv, offset;
> +
> +       /* Check response error code */
> +       msg->result = in_msg->ec_response.result;
> +       rv = cros_ec_check_result(ec_dev, msg);
> +       if (rv < 0)
> +               return rv;
> +
> +       if (in_msg->ec_response.data_len > msg->insize) {
> +               dev_err(ec_dev->dev, "Packet too long (%d bytes, expected %d)",
> +                       in_msg->ec_response.data_len, msg->insize);
> +               return -ENOSPC;
> +       }
> +
> +       /* Copy response packet payload and compute checksum */
> +       for (i = 0; i < sizeof(struct ec_host_response); i++)
> +               sum += ((u8 *)in_msg)[IN_MSG_EC_RESPONSE_PREAMBLE + i];
> +
> +       offset = sizeof(struct cros_ish_in_msg);
> +       for (i = 0; i < in_msg->ec_response.data_len; i++)
> +               sum += msg->data[i] = ((u8 *)in_msg)[offset + i];
> +
> +       if (sum) {
> +               dev_dbg(ec_dev->dev, "Bad received packet checksum %d\n", sum);
> +               return -EBADMSG;
> +       }
> +
> +       return 0;
> +}
> +
> +static int cros_ec_pkt_xfer_ish(struct cros_ec_device *ec_dev,
> +                               struct cros_ec_command *msg)
> +{
> +       int rv;
> +       struct ishtp_cl *cros_ish_cl = ec_dev->priv;
> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +       struct device *dev = cl_data_to_dev(client_data);
> +       struct cros_ish_in_msg *in_msg = (struct cros_ish_in_msg *)ec_dev->din;
> +       struct cros_ish_out_msg *out_msg =
> +               (struct cros_ish_out_msg *)ec_dev->dout;
> +       size_t in_size = sizeof(struct cros_ish_in_msg) + msg->insize;
> +       size_t out_size = sizeof(struct cros_ish_out_msg) + msg->outsize;
> +
> +       /* Proceed only if reset-init is not in progress */
> +       if (!down_read_trylock(&init_lock)) {
> +               dev_warn(dev,
> +                        "Host is not ready to send messages to ISH. Try again\n");
> +               return -EAGAIN;
> +       }
> +
> +       /* Sanity checks */
> +       if (in_size > ec_dev->din_size) {
> +               dev_err(dev,
> +                       "Incoming payload size %zu is too large for ec_dev->din_size %d\n",
> +                       in_size, ec_dev->din_size);
> +               return -EMSGSIZE;
> +       }
> +
> +       if (out_size > ec_dev->dout_size) {
> +               dev_err(dev,
> +                       "Outgoing payload size %zu is too large for ec_dev->dout_size %d\n",
> +                       out_size, ec_dev->dout_size);
> +               return -EMSGSIZE;
> +       }
> +
> +       /* Prepare the package to be sent over ISH TP */
> +       out_msg->hdr.channel = CROS_EC_COMMAND;
> +       out_msg->hdr.status = 0;
> +
> +       ec_dev->dout += OUT_MSG_EC_REQUEST_PREAMBLE;
> +       cros_ec_prepare_tx(ec_dev, msg);
> +       ec_dev->dout -= OUT_MSG_EC_REQUEST_PREAMBLE;
> +
> +       dev_dbg(dev,
> +               "out_msg: struct_ver=0x%x checksum=0x%x command=0x%x command_ver=0x%x data_len=0x%x\n",
> +               out_msg->ec_request.struct_version,
> +               out_msg->ec_request.checksum,
> +               out_msg->ec_request.command,
> +               out_msg->ec_request.command_version,
> +               out_msg->ec_request.data_len);
> +
> +       /* Send command to ISH EC firmware and read response */
> +       rv = ish_send(client_data,
> +                     (u8 *)out_msg, out_size,
> +                     (u8 *)in_msg, in_size);
> +       if (rv < 0)
> +               goto end_error;
> +
> +       rv = prepare_cros_ec_rx(ec_dev, in_msg, msg);
> +       if (rv)
> +               goto end_error;
> +
> +       rv = in_msg->ec_response.data_len;
> +
> +       dev_dbg(dev,
> +               "in_msg: struct_ver=0x%x checksum=0x%x result=0x%x data_len=0x%x\n",
> +               in_msg->ec_response.struct_version,
> +               in_msg->ec_response.checksum,
> +               in_msg->ec_response.result,
> +               in_msg->ec_response.data_len);
> +
> +end_error:
> +       if (msg->command == EC_CMD_REBOOT_EC)
> +               msleep(EC_REBOOT_DELAY_MS);
> +
> +       up_read(&init_lock);
> +
> +       return rv;
> +}
> +
> +static int cros_ec_dev_init(struct ishtp_cl_data *client_data)
> +{
> +       struct cros_ec_device *ec_dev;
> +       struct device *dev = cl_data_to_dev(client_data);
> +
> +       ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
> +       if (!ec_dev)
> +               return -ENOMEM;
> +
> +       client_data->ec_dev = ec_dev;
> +       dev->driver_data = ec_dev;
> +
> +       ec_dev->dev = dev;
> +       ec_dev->priv = client_data->cros_ish_cl;
> +       ec_dev->cmd_xfer = NULL;
> +       ec_dev->pkt_xfer = cros_ec_pkt_xfer_ish;
> +       ec_dev->phys_name = dev_name(dev);
> +       ec_dev->din_size = sizeof(struct cros_ish_in_msg) +
> +                          sizeof(struct ec_response_get_protocol_info);
> +       ec_dev->dout_size = sizeof(struct cros_ish_out_msg);
> +
> +       return cros_ec_register(ec_dev);
> +}
> +
> +static void reset_handler(struct work_struct *work)
> +{
> +       int rv;
> +       struct device *dev;
> +       struct ishtp_cl *cros_ish_cl;
> +       struct ishtp_cl_device *cl_device;
> +       struct ishtp_cl_data *client_data =
> +               container_of(work, struct ishtp_cl_data, work_ishtp_reset);
> +
> +       /* Lock for reset to complete */
> +       down_write(&init_lock);
> +
> +       cros_ish_cl = client_data->cros_ish_cl;
> +       cl_device = client_data->cl_device;
> +
> +       /* Unlink, flush queues & start again */
> +       ishtp_cl_unlink(cros_ish_cl);
> +       ishtp_cl_flush_queues(cros_ish_cl);
> +       ishtp_cl_free(cros_ish_cl);
> +
> +       cros_ish_cl = ishtp_cl_allocate(cl_device);
> +       if (!cros_ish_cl) {
> +               up_write(&init_lock);
> +               return;
> +       }
> +
> +       ishtp_set_drvdata(cl_device, cros_ish_cl);
> +       ishtp_set_client_data(cros_ish_cl, client_data);
> +       client_data->cros_ish_cl = cros_ish_cl;
> +
> +       rv = cros_ish_init(cros_ish_cl);
> +       if (rv) {
> +               ishtp_cl_free(cros_ish_cl);
> +               dev_err(cl_data_to_dev(client_data), "Reset Failed\n");
> +               up_write(&init_lock);
> +               return;
> +       }
> +
> +       /* Refresh ec_dev device pointers */
> +       client_data->ec_dev->priv = client_data->cros_ish_cl;
> +       dev = cl_data_to_dev(client_data);
> +       dev->driver_data = client_data->ec_dev;
> +
> +       dev_info(cl_data_to_dev(client_data), "Chrome EC ISH reset done\n");
> +
> +       up_write(&init_lock);
> +}
> +
> +/**
> + * cros_ec_ishtp_probe() - ISHTP client driver probe callback
> + * @cl_device:         ISHTP client device instance
> + *
> + * Return: 0 for success, negative error code for failure.
> + */
> +static int cros_ec_ishtp_probe(struct ishtp_cl_device *cl_device)
> +{
> +       int rv;
> +       struct ishtp_cl *cros_ish_cl;
> +       struct ishtp_cl_data *client_data =
> +               devm_kzalloc(ishtp_device(cl_device),
> +                            sizeof(*client_data), GFP_KERNEL);
> +       if (!client_data)
> +               return -ENOMEM;
> +
> +       /* Lock for initialization to complete */
> +       down_write(&init_lock);
> +
> +       cros_ish_cl = ishtp_cl_allocate(cl_device);
> +       if (!cros_ish_cl) {
> +               rv = -ENOMEM;
> +               goto end_ishtp_cl_alloc_error;
> +       }
> +
> +       ishtp_set_drvdata(cl_device, cros_ish_cl);
> +       ishtp_set_client_data(cros_ish_cl, client_data);
> +       client_data->cros_ish_cl = cros_ish_cl;
> +       client_data->cl_device = cl_device;
> +
> +       init_waitqueue_head(&client_data->response.wait_queue);
> +
> +       INIT_WORK(&client_data->work_ishtp_reset,
> +                 reset_handler);
> +       INIT_WORK(&client_data->work_ec_evt,
> +                 ish_evt_handler);
> +
> +       rv = cros_ish_init(cros_ish_cl);
> +       if (rv)
> +               goto end_ishtp_cl_init_error;
> +
> +       ishtp_get_device(cl_device);
> +
> +       up_write(&init_lock);
> +
> +       /* Register croc_ec_dev mfd */
> +       rv = cros_ec_dev_init(client_data);
> +       if (rv)
> +               goto end_cros_ec_dev_init_error;
> +
> +       return 0;
> +
> +end_cros_ec_dev_init_error:
> +       ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
> +       ishtp_cl_disconnect(cros_ish_cl);
> +       ishtp_cl_unlink(cros_ish_cl);
> +       ishtp_cl_flush_queues(cros_ish_cl);
> +       ishtp_put_device(cl_device);
> +end_ishtp_cl_init_error:
> +       ishtp_cl_free(cros_ish_cl);
> +end_ishtp_cl_alloc_error:
> +       up_write(&init_lock);
> +       return rv;
> +}
> +
> +/**
> + * cros_ec_ishtp_remove() - ISHTP client driver remove callback
> + * @cl_device:         ISHTP client device instance
> + *
> + * Return: 0
> + */
> +static int cros_ec_ishtp_remove(struct ishtp_cl_device *cl_device)
> +{
> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +       cancel_work_sync(&client_data->work_ishtp_reset);
> +       cancel_work_sync(&client_data->work_ec_evt);
> +       cros_ish_deinit(cros_ish_cl);
> +       ishtp_put_device(cl_device);
> +
> +       return 0;
> +}
> +
> +/**
> + * cros_ec_ishtp_reset() - ISHTP client driver reset callback
> + * @cl_device:         ISHTP client device instance
> + *
> + * Return: 0
> + */
> +static int cros_ec_ishtp_reset(struct ishtp_cl_device *cl_device)
> +{
> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +       schedule_work(&client_data->work_ishtp_reset);
> +
> +       return 0;
> +}
> +
> +/**
> + * cros_ec_ishtp_suspend() - ISHTP client driver suspend callback
> + * @device:    device instance
> + *
> + * Return: 0 for success, negative error code for failure.
> + */
> +static int __maybe_unused cros_ec_ishtp_suspend(struct device *device)
> +{
> +       struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +       return cros_ec_suspend(client_data->ec_dev);
> +}
> +
> +/**
> + * cros_ec_ishtp_resume() - ISHTP client driver resume callback
> + * @device:    device instance
> + *
> + * Return: 0 for success, negative error code for failure.
> + */
> +static int __maybe_unused cros_ec_ishtp_resume(struct device *device)
> +{
> +       struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +       return cros_ec_resume(client_data->ec_dev);
> +}
> +
> +static SIMPLE_DEV_PM_OPS(cros_ec_ishtp_pm_ops, cros_ec_ishtp_suspend,
> +                        cros_ec_ishtp_resume);
> +
> +static struct ishtp_cl_driver  cros_ec_ishtp_driver = {
> +       .name = "cros_ec_ishtp",
> +       .guid = &cros_ish_guid,
> +       .probe = cros_ec_ishtp_probe,
> +       .remove = cros_ec_ishtp_remove,
> +       .reset = cros_ec_ishtp_reset,
> +       .driver = {
> +               .pm = &cros_ec_ishtp_pm_ops,
> +       },
> +};
> +
> +static int __init cros_ec_ishtp_mod_init(void)
> +{
> +       return ishtp_cl_driver_register(&cros_ec_ishtp_driver, THIS_MODULE);
> +}
> +
> +static void __exit cros_ec_ishtp_mod_exit(void)
> +{
> +       ishtp_cl_driver_unregister(&cros_ec_ishtp_driver);
> +}
> +
> +module_init(cros_ec_ishtp_mod_init);
> +module_exit(cros_ec_ishtp_mod_exit);
> +
> +MODULE_DESCRIPTION("ChromeOS EC ISHTP Client Driver");
> +MODULE_AUTHOR("Rushikesh S Kadam <rushikesh.s.kadam@intel.com>");
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("ishtp:*");
> --
> 1.9.1
>

Re: [PATCH v3] platform: chrome: Add ChromeOS EC ISHTP driver

[Enric Balletbo i Serra]

Hi,

On 10/4/19 17:31, Jett Rink wrote:
> Reviewed-by: Jett Rink <jettrink@chromium.org>
> Tested-by: Jett Rink <jettrink@chromium.org>
> 
> 
> On Sun, Apr 7, 2019 at 6:10 AM Rushikesh S Kadam
> <rushikesh.s.kadam@intel.com> wrote:
>>
>> This driver implements a slim layer to enable the ChromeOS
>> EC kernel stack (cros_ec) to communicate with ChromeOS EC
>> firmware running on the Intel Integrated Sensor Hub (ISH).
>>
>> The driver registers a ChromeOS EC MFD device to connect
>> with cros_ec kernel stack (upper layer), and it registers a
>> client with the ISH Transport Protocol bus (lower layer) to
>> talk with the ISH firwmare. See description of the ISHTP
>> protocol at Documentation/hid/intel-ish-hid.txt
>>
>> Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
>> ---
>>
>> v3
>>  - Made several changes to improve code readability. Replaced
>>    multiple cl_data_to_dev(client_data) with dev variable. Use
>>    reverse Xmas tree for variable defintion where it made sense.
>>    Dropped few debug prints. Add docstring for function
>>    prepare_cros_ec_rx().
>>  - Fix code in function prepare_cros_ec_rx() under label
>>    end_cros_ec_dev_init_error.
>>  - Recycle buffer in process_recv() on failing to obtain the
>>    semaphore.
>>  - Increase ISHTP TX/RX ring buffer size to 8.
>>  - Alphabetically ordered CROS_EC_ISHTP entries in Makefile and
>>    Kconfig.
>>  - Updated commit message.
>>
>> v2
>>  - Dropped unused "reset" parameter in function cros_ec_init()
>>  - Change driver name to cros_ec_ishtp to be consistent with other
>>    references in the code.
>>  - Fixed a few typos.
>>
>> v1
>>  - Initial version
>>
>>  drivers/platform/chrome/Kconfig         |  13 +
>>  drivers/platform/chrome/Makefile        |   1 +
>>  drivers/platform/chrome/cros_ec_ishtp.c | 765 ++++++++++++++++++++++++++++++++
>>  3 files changed, 779 insertions(+)
>>  create mode 100644 drivers/platform/chrome/cros_ec_ishtp.c
>>
>> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
>> index 16b1615..5848179 100644
>> --- a/drivers/platform/chrome/Kconfig
>> +++ b/drivers/platform/chrome/Kconfig
>> @@ -62,6 +62,19 @@ config CROS_EC_I2C
>>           a checksum. Failing accesses will be retried three times to
>>           improve reliability.
>>
>> +config CROS_EC_ISHTP
>> +       tristate "ChromeOS Embedded Controller (ISHTP)"
>> +       depends on MFD_CROS_EC
>> +       depends on INTEL_ISH_HID
>> +       help
>> +         If you say Y here, you get support for talking to the ChromeOS EC
>> +         firmware running on Intel Integrated Sensor Hub (ISH), using the
>> +         ISH Transport protocol (ISH-TP). This uses a simple byte-level
>> +         protocol with a checksum.
>> +
>> +         To compile this driver as a module, choose M here: the
>> +         module will be called cros_ec_ishtp.
>> +
>>  config CROS_EC_SPI
>>         tristate "ChromeOS Embedded Controller (SPI)"
>>         depends on MFD_CROS_EC && SPI
>> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
>> index cd591bf..4efe102 100644
>> --- a/drivers/platform/chrome/Makefile
>> +++ b/drivers/platform/chrome/Makefile
>> @@ -7,6 +7,7 @@ cros_ec_ctl-objs                        := cros_ec_sysfs.o cros_ec_lightbar.o \
>>                                            cros_ec_vbc.o cros_ec_debugfs.o
>>  obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
>>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
>> +obj-$(CONFIG_CROS_EC_ISHTP)            += cros_ec_ishtp.o
>>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
>>  cros_ec_lpcs-objs                      := cros_ec_lpc.o cros_ec_lpc_reg.o
>>  cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC) += cros_ec_lpc_mec.o
>> diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c
>> new file mode 100644
>> index 0000000..b1d19c4
>> --- /dev/null
>> +++ b/drivers/platform/chrome/cros_ec_ishtp.c
>> @@ -0,0 +1,765 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * ISHTP client driver for talking to the Chrome OS EC firmware running
>> + * on Intel Integrated Sensor Hub (ISH) using the ISH Transport protocol
>> + * (ISH-TP).
>> + *
>> + * Copyright (c) 2019, Intel Corporation.
>> + */
>> +
>> +#include <linux/delay.h>
>> +#include <linux/mfd/core.h>
>> +#include <linux/mfd/cros_ec.h>
>> +#include <linux/mfd/cros_ec_commands.h>
>> +#include <linux/module.h>
>> +#include <linux/pci.h>
>> +#include <linux/intel-ish-client-if.h>
>> +

I think that this patch depends on another patchset that's in linux-next but
diddn't land yet to mainline. Do you know if the dependencies are queued for
next merge window? Can you provide the exact patches that this patch depends on?

Thanks,
 Enric


>> +/*
>> + * ISH TX/RX ring buffer pool size
>> + *
>> + * The AP->ISH messages and corresponding ISH->AP responses are
>> + * serialized. We need 1 TX and 1 RX buffer for these.
>> + *
>> + * The MKBP ISH->AP events are serialized. We need one additional RX
>> + * buffer for them.
>> + */
>> +#define CROS_ISH_CL_TX_RING_SIZE               8
>> +#define CROS_ISH_CL_RX_RING_SIZE               8
>> +
>> +/* ISH CrOS EC Host Commands */
>> +enum cros_ec_ish_channel {
>> +       CROS_EC_COMMAND = 1,                    /* AP->ISH message */
>> +       CROS_MKBP_EVENT = 2,                    /* ISH->AP events */
>> +};
>> +
>> +/*
>> + * ISH firmware timeout for 1 message send failure is 1Hz, and the
>> + * firmware will retry 2 times, so 3Hz is used for timeout.
>> + */
>> +#define ISHTP_SEND_TIMEOUT                     (3 * HZ)
>> +
>> +/* ISH Transport CrOS EC ISH client unique GUID */
>> +static const guid_t cros_ish_guid =
>> +       GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
>> +                 0xb0, 0xd8, 0x9e, 0x7c, 0xda, 0xe0, 0xd6, 0xa0);
>> +
>> +struct header {
>> +       u8 channel;
>> +       u8 status;
>> +       u8 reserved[2];
>> +} __packed;
>> +
>> +struct cros_ish_out_msg {
>> +       struct header hdr;
>> +       struct ec_host_request ec_request;
>> +} __packed;
>> +
>> +struct cros_ish_in_msg {
>> +       struct header hdr;
>> +       struct ec_host_response ec_response;
>> +} __packed;
>> +
>> +#define IN_MSG_EC_RESPONSE_PREAMBLE                                    \
>> +       offsetof(struct cros_ish_in_msg, ec_response)
>> +
>> +#define OUT_MSG_EC_REQUEST_PREAMBLE                                    \
>> +       offsetof(struct cros_ish_out_msg, ec_request)
>> +
>> +#define cl_data_to_dev(client_data) ishtp_device((client_data)->cl_device)
>> +
>> +/*
>> + * The Read-Write Semaphore is used to prevent message TX or RX while
>> + * the ishtp client is being initialized or undergoing reset.
>> + *
>> + * The readers are the kernel function calls responsible for IA->ISH
>> + * and ISH->AP messaging.
>> + *
>> + * The writers are .reset() and .probe() function.
>> + */
>> +DECLARE_RWSEM(init_lock);
>> +
>> +/**
>> + * struct response_info - Encapsulate firmware response related
>> + *                     information for passing between function
>> + *                     ish_send() and process_recv() callback.
>> + * @data:              Copy the data received from firmware here.
>> + * @max_size:          Max size allocated for the @data buffer. If the
>> + *                     received data exceeds this value, we log an
>> + *                     error.
>> + * @size:              Actual size of data received from firmware.
>> + * @error:             0 for success, negative error code for a
>> + *                     failure in function process_recv().
>> + * @received:          Set to true on receiving a valid firmware
>> + *                     response to host command
>> + * @wait_queue:                Wait queue for Host firmware loading where the
>> + *                     client sends message to ISH firmware and waits
>> + *                     for response
>> + */
>> +struct response_info {
>> +       void *data;
>> +       size_t max_size;
>> +       size_t size;
>> +       int error;
>> +       bool received;
>> +       wait_queue_head_t wait_queue;
>> +};
>> +
>> +/**
>> + * struct ishtp_cl_data - Encapsulate per ISH TP Client.
>> + * @cros_ish_cl:       ISHTP firmware client instance.
>> + * @cl_device:         ISHTP client device instance.
>> + * @response:          Firmware response information for passing
>> + *                     between function ish_send() and process_recv()
>> + *                     callback.
>> + * @work_ishtp_reset:  Work queue reset handling.
>> + * @work_ec_evt:       Work queue for EC events.
>> + * @ec_dev:            CrOS EC MFD device.
>> + *
>> + * This structure is used to store per client data.
>> + */
>> +struct ishtp_cl_data {
>> +       struct ishtp_cl *cros_ish_cl;
>> +       struct ishtp_cl_device *cl_device;
>> +
>> +       /*
>> +        * Used for passing firmware response information between
>> +        * ish_send() and process_recv() callback.
>> +        */
>> +       struct response_info response;
>> +
>> +       struct work_struct work_ishtp_reset;
>> +       struct work_struct work_ec_evt;
>> +       struct cros_ec_device *ec_dev;
>> +};
>> +
>> +/**
>> + * ish_evt_handler - ISH to AP event handler
>> + * @work:              Work struct
>> + */
>> +static void ish_evt_handler(struct work_struct *work)
>> +{
>> +       struct ishtp_cl_data *client_data =
>> +               container_of(work, struct ishtp_cl_data, work_ec_evt);
>> +       struct cros_ec_device *ec_dev = client_data->ec_dev;
>> +
>> +       if (cros_ec_get_next_event(ec_dev, NULL) > 0) {
>> +               blocking_notifier_call_chain(&ec_dev->event_notifier,
>> +                                            0, ec_dev);
>> +       }
>> +}
>> +
>> +/**
>> + * ish_send() - Send message from host to firmware
>> + * @client_data:       Client data instance
>> + * @out_msg:           Message buffer to be sent to firmware
>> + * @out_size:          Size of out going message
>> + * @in_msg:            Message buffer where the incoming data copied.
>> + *                     This buffer is allocated by calling
>> + * @in_size:           Max size of incoming message
>> + *
>> + * Return: Number of bytes copied in the in_msg on success, negative
>> + * error code on failure.
>> + */
>> +static int ish_send(struct ishtp_cl_data *client_data,
>> +                   u8 *out_msg, size_t out_size,
>> +                   u8 *in_msg, size_t in_size)
>> +{
>> +       int rv;
>> +       struct header *out_hdr = (struct header *)out_msg;
>> +       struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl;
>> +
>> +       dev_dbg(cl_data_to_dev(client_data),
>> +               "%s: channel=%02u status=%02u\n",
>> +               __func__, out_hdr->channel, out_hdr->status);
>> +
>> +       /* Setup for incoming response */
>> +       client_data->response.data = in_msg;
>> +       client_data->response.max_size = in_size;
>> +       client_data->response.error = 0;
>> +       client_data->response.received = false;
>> +
>> +       rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
>> +       if (rv) {
>> +               dev_err(cl_data_to_dev(client_data),
>> +                       "ishtp_cl_send error %d\n", rv);
>> +               return rv;
>> +       }
>> +
>> +       wait_event_interruptible_timeout(client_data->response.wait_queue,
>> +                                        client_data->response.received,
>> +                                        ISHTP_SEND_TIMEOUT);
>> +       if (!client_data->response.received) {
>> +               dev_err(cl_data_to_dev(client_data),
>> +                       "Timed out for response to host message\n");
>> +               return -ETIMEDOUT;
>> +       }
>> +
>> +       if (client_data->response.error < 0)
>> +               return client_data->response.error;
>> +
>> +       return client_data->response.size;
>> +}
>> +
>> +/**
>> + * process_recv() -    Received and parse incoming packet
>> + * @cros_ish_cl:       Client instance to get stats
>> + * @rb_in_proc:                Host interface message buffer
>> + *
>> + * Parse the incoming packet. If it is a response packet then it will
>> + * update per instance flags and wake up the caller waiting to for the
>> + * response. If it is an event packet then it will schedule event work.
>> + */
>> +static void process_recv(struct ishtp_cl *cros_ish_cl,
>> +                        struct ishtp_cl_rb *rb_in_proc)
>> +{
>> +       size_t data_len = rb_in_proc->buf_idx;
>> +       struct ishtp_cl_data *client_data =
>> +               ishtp_get_client_data(cros_ish_cl);
>> +       struct device *dev = cl_data_to_dev(client_data);
>> +       struct cros_ish_in_msg *in_msg =
>> +               (struct cros_ish_in_msg *)rb_in_proc->buffer.data;
>> +
>> +       /* Proceed only if reset or init is not in progress */
>> +       if (!down_read_trylock(&init_lock)) {
>> +               /* Free the buffer */
>> +               ishtp_cl_io_rb_recycle(rb_in_proc);
>> +               dev_warn(dev,
>> +                        "Host is not ready to receive incoming messages\n");
>> +               return;
>> +       }
>> +
>> +       /*
>> +        * All firmware messages contain a header. Check the buffer size
>> +        * before accessing elements inside.
>> +        */
>> +       if (!rb_in_proc->buffer.data) {
>> +               dev_warn(dev, "rb_in_proc->buffer.data returned null");
>> +               client_data->response.error = -EBADMSG;
>> +               goto end_error;
>> +       }
>> +
>> +       if (data_len < sizeof(struct header)) {
>> +               dev_err(dev, "data size %zu is less than header %zu\n",
>> +                       data_len, sizeof(struct header));
>> +               client_data->response.error = -EMSGSIZE;
>> +               goto end_error;
>> +       }
>> +
>> +       dev_dbg(dev, "channel=%02u status=%02u\n",
>> +               in_msg->hdr.channel, in_msg->hdr.status);
>> +
>> +       switch (in_msg->hdr.channel) {
>> +       case CROS_EC_COMMAND:
>> +               /* Sanity check */
>> +               if (!client_data->response.data) {
>> +                       dev_err(dev,
>> +                               "Receiving buffer is null. Should be allocated by calling function\n");
>> +                       client_data->response.error = -EINVAL;
>> +                       goto error_wake_up;
>> +               }
>> +
>> +               if (client_data->response.received) {
>> +                       dev_err(dev,
>> +                               "Previous firmware message not yet processed\n");
>> +                       client_data->response.error = -EINVAL;
>> +                       goto error_wake_up;
>> +               }
>> +
>> +               if (data_len > client_data->response.max_size) {
>> +                       dev_err(dev,
>> +                               "Received buffer size %zu is larger than allocated buffer %zu\n",
>> +                               data_len, client_data->response.max_size);
>> +                       client_data->response.error = -EMSGSIZE;
>> +                       goto error_wake_up;
>> +               }
>> +
>> +               if (in_msg->hdr.status) {
>> +                       dev_err(dev, "firmware returned status %d\n",
>> +                               in_msg->hdr.status);
>> +                       client_data->response.error = -EIO;
>> +                       goto error_wake_up;
>> +               }
>> +
>> +               /* Update the actual received buffer size */
>> +               client_data->response.size = data_len;
>> +
>> +               /*
>> +                * Copy the buffer received in firmware response for the
>> +                * calling thread.
>> +                */
>> +               memcpy(client_data->response.data,
>> +                      rb_in_proc->buffer.data, data_len);
>> +
>> +               /* Set flag before waking up the caller */
>> +               client_data->response.received = true;
>> +error_wake_up:
>> +               /* Wake the calling thread */
>> +               wake_up_interruptible(&client_data->response.wait_queue);
>> +
>> +               break;
>> +
>> +       case CROS_MKBP_EVENT:
>> +               /* The event system doesn't send any data in buffer */
>> +               schedule_work(&client_data->work_ec_evt);
>> +
>> +               break;
>> +
>> +       default:
>> +               dev_err(dev, "Invalid channel=%02d\n", in_msg->hdr.channel);
>> +       }
>> +
>> +end_error:
>> +       /* Free the buffer */
>> +       ishtp_cl_io_rb_recycle(rb_in_proc);
>> +
>> +       up_read(&init_lock);
>> +}
>> +
>> +/**
>> + * ish_event_cb() - bus driver callback for incoming message
>> + * @cl_device:         ISHTP client device for which this message is
>> + *                     targeted.
>> + *
>> + * Remove the packet from the list and process the message by calling
>> + * process_recv.
>> + */
>> +static void ish_event_cb(struct ishtp_cl_device *cl_device)
>> +{
>> +       struct ishtp_cl_rb *rb_in_proc;
>> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
>> +
>> +       while ((rb_in_proc = ishtp_cl_rx_get_rb(cros_ish_cl)) != NULL) {
>> +               /* Decide what to do with received data */
>> +               process_recv(cros_ish_cl, rb_in_proc);
>> +       }
>> +}
>> +
>> +/**
>> + * cros_ish_init() - Init function for ISHTP client
>> + * @cros_ish_cl:       ISHTP client instance
>> + *
>> + * This function complete the initializtion of the client.
>> + *
>> + * Return: 0 for success, negative error code for failure.
>> + */
>> +static int cros_ish_init(struct ishtp_cl *cros_ish_cl)
>> +{
>> +       int rv;
>> +       struct ishtp_device *dev;
>> +       struct ishtp_fw_client *fw_client;
>> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
>> +
>> +       rv = ishtp_cl_link(cros_ish_cl);
>> +       if (rv) {
>> +               dev_err(cl_data_to_dev(client_data),
>> +                       "ishtp_cl_link failed\n");
>> +               return rv;
>> +       }
>> +
>> +       dev = ishtp_get_ishtp_device(cros_ish_cl);
>> +
>> +       /* Connect to firmware client */
>> +       ishtp_set_tx_ring_size(cros_ish_cl, CROS_ISH_CL_TX_RING_SIZE);
>> +       ishtp_set_rx_ring_size(cros_ish_cl, CROS_ISH_CL_RX_RING_SIZE);
>> +
>> +       fw_client = ishtp_fw_cl_get_client(dev, &cros_ish_guid);
>> +       if (!fw_client) {
>> +               dev_err(cl_data_to_dev(client_data),
>> +                       "ish client uuid not found\n");
>> +               rv = -ENOENT;
>> +               goto err_cl_unlink;
>> +       }
>> +
>> +       ishtp_cl_set_fw_client_id(cros_ish_cl,
>> +                                 ishtp_get_fw_client_id(fw_client));
>> +       ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_CONNECTING);
>> +
>> +       rv = ishtp_cl_connect(cros_ish_cl);
>> +       if (rv) {
>> +               dev_err(cl_data_to_dev(client_data),
>> +                       "client connect fail\n");
>> +               goto err_cl_unlink;
>> +       }
>> +
>> +       ishtp_register_event_cb(client_data->cl_device, ish_event_cb);
>> +       return 0;
>> +
>> +err_cl_unlink:
>> +       ishtp_cl_unlink(cros_ish_cl);
>> +       return rv;
>> +}
>> +
>> +/**
>> + * cros_ish_deinit() - Deinit function for ISHTP client
>> + * @cros_ish_cl:       ISHTP client instance
>> + *
>> + * Unlink and free cros_ec client
>> + */
>> +static void cros_ish_deinit(struct ishtp_cl *cros_ish_cl)
>> +{
>> +       ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
>> +       ishtp_cl_disconnect(cros_ish_cl);
>> +       ishtp_cl_unlink(cros_ish_cl);
>> +       ishtp_cl_flush_queues(cros_ish_cl);
>> +
>> +       /* Disband and free all Tx and Rx client-level rings */
>> +       ishtp_cl_free(cros_ish_cl);
>> +}
>> +
>> +/**
>> + * prepare_cros_ec_rx() - Check & prepare receive buffer
>> + * @in_msg:            Incoming message buffer
>> + * @cros_ec_command    cros_ec command used to send & receive data
>> + *
>> + * Check the received buffer. Convert to cros_ec_command format.
>> + */
>> +static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
>> +                             const struct cros_ish_in_msg *in_msg,
>> +                             struct cros_ec_command *msg)
>> +{
>> +       u8 sum = 0;
>> +       int i, rv, offset;
>> +
>> +       /* Check response error code */
>> +       msg->result = in_msg->ec_response.result;
>> +       rv = cros_ec_check_result(ec_dev, msg);
>> +       if (rv < 0)
>> +               return rv;
>> +
>> +       if (in_msg->ec_response.data_len > msg->insize) {
>> +               dev_err(ec_dev->dev, "Packet too long (%d bytes, expected %d)",
>> +                       in_msg->ec_response.data_len, msg->insize);
>> +               return -ENOSPC;
>> +       }
>> +
>> +       /* Copy response packet payload and compute checksum */
>> +       for (i = 0; i < sizeof(struct ec_host_response); i++)
>> +               sum += ((u8 *)in_msg)[IN_MSG_EC_RESPONSE_PREAMBLE + i];
>> +
>> +       offset = sizeof(struct cros_ish_in_msg);
>> +       for (i = 0; i < in_msg->ec_response.data_len; i++)
>> +               sum += msg->data[i] = ((u8 *)in_msg)[offset + i];
>> +
>> +       if (sum) {
>> +               dev_dbg(ec_dev->dev, "Bad received packet checksum %d\n", sum);
>> +               return -EBADMSG;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static int cros_ec_pkt_xfer_ish(struct cros_ec_device *ec_dev,
>> +                               struct cros_ec_command *msg)
>> +{
>> +       int rv;
>> +       struct ishtp_cl *cros_ish_cl = ec_dev->priv;
>> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
>> +       struct device *dev = cl_data_to_dev(client_data);
>> +       struct cros_ish_in_msg *in_msg = (struct cros_ish_in_msg *)ec_dev->din;
>> +       struct cros_ish_out_msg *out_msg =
>> +               (struct cros_ish_out_msg *)ec_dev->dout;
>> +       size_t in_size = sizeof(struct cros_ish_in_msg) + msg->insize;
>> +       size_t out_size = sizeof(struct cros_ish_out_msg) + msg->outsize;
>> +
>> +       /* Proceed only if reset-init is not in progress */
>> +       if (!down_read_trylock(&init_lock)) {
>> +               dev_warn(dev,
>> +                        "Host is not ready to send messages to ISH. Try again\n");
>> +               return -EAGAIN;
>> +       }
>> +
>> +       /* Sanity checks */
>> +       if (in_size > ec_dev->din_size) {
>> +               dev_err(dev,
>> +                       "Incoming payload size %zu is too large for ec_dev->din_size %d\n",
>> +                       in_size, ec_dev->din_size);
>> +               return -EMSGSIZE;
>> +       }
>> +
>> +       if (out_size > ec_dev->dout_size) {
>> +               dev_err(dev,
>> +                       "Outgoing payload size %zu is too large for ec_dev->dout_size %d\n",
>> +                       out_size, ec_dev->dout_size);
>> +               return -EMSGSIZE;
>> +       }
>> +
>> +       /* Prepare the package to be sent over ISH TP */
>> +       out_msg->hdr.channel = CROS_EC_COMMAND;
>> +       out_msg->hdr.status = 0;
>> +
>> +       ec_dev->dout += OUT_MSG_EC_REQUEST_PREAMBLE;
>> +       cros_ec_prepare_tx(ec_dev, msg);
>> +       ec_dev->dout -= OUT_MSG_EC_REQUEST_PREAMBLE;
>> +
>> +       dev_dbg(dev,
>> +               "out_msg: struct_ver=0x%x checksum=0x%x command=0x%x command_ver=0x%x data_len=0x%x\n",
>> +               out_msg->ec_request.struct_version,
>> +               out_msg->ec_request.checksum,
>> +               out_msg->ec_request.command,
>> +               out_msg->ec_request.command_version,
>> +               out_msg->ec_request.data_len);
>> +
>> +       /* Send command to ISH EC firmware and read response */
>> +       rv = ish_send(client_data,
>> +                     (u8 *)out_msg, out_size,
>> +                     (u8 *)in_msg, in_size);
>> +       if (rv < 0)
>> +               goto end_error;
>> +
>> +       rv = prepare_cros_ec_rx(ec_dev, in_msg, msg);
>> +       if (rv)
>> +               goto end_error;
>> +
>> +       rv = in_msg->ec_response.data_len;
>> +
>> +       dev_dbg(dev,
>> +               "in_msg: struct_ver=0x%x checksum=0x%x result=0x%x data_len=0x%x\n",
>> +               in_msg->ec_response.struct_version,
>> +               in_msg->ec_response.checksum,
>> +               in_msg->ec_response.result,
>> +               in_msg->ec_response.data_len);
>> +
>> +end_error:
>> +       if (msg->command == EC_CMD_REBOOT_EC)
>> +               msleep(EC_REBOOT_DELAY_MS);
>> +
>> +       up_read(&init_lock);
>> +
>> +       return rv;
>> +}
>> +
>> +static int cros_ec_dev_init(struct ishtp_cl_data *client_data)
>> +{
>> +       struct cros_ec_device *ec_dev;
>> +       struct device *dev = cl_data_to_dev(client_data);
>> +
>> +       ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
>> +       if (!ec_dev)
>> +               return -ENOMEM;
>> +
>> +       client_data->ec_dev = ec_dev;
>> +       dev->driver_data = ec_dev;
>> +
>> +       ec_dev->dev = dev;
>> +       ec_dev->priv = client_data->cros_ish_cl;
>> +       ec_dev->cmd_xfer = NULL;
>> +       ec_dev->pkt_xfer = cros_ec_pkt_xfer_ish;
>> +       ec_dev->phys_name = dev_name(dev);
>> +       ec_dev->din_size = sizeof(struct cros_ish_in_msg) +
>> +                          sizeof(struct ec_response_get_protocol_info);
>> +       ec_dev->dout_size = sizeof(struct cros_ish_out_msg);
>> +
>> +       return cros_ec_register(ec_dev);
>> +}
>> +
>> +static void reset_handler(struct work_struct *work)
>> +{
>> +       int rv;
>> +       struct device *dev;
>> +       struct ishtp_cl *cros_ish_cl;
>> +       struct ishtp_cl_device *cl_device;
>> +       struct ishtp_cl_data *client_data =
>> +               container_of(work, struct ishtp_cl_data, work_ishtp_reset);
>> +
>> +       /* Lock for reset to complete */
>> +       down_write(&init_lock);
>> +
>> +       cros_ish_cl = client_data->cros_ish_cl;
>> +       cl_device = client_data->cl_device;
>> +
>> +       /* Unlink, flush queues & start again */
>> +       ishtp_cl_unlink(cros_ish_cl);
>> +       ishtp_cl_flush_queues(cros_ish_cl);
>> +       ishtp_cl_free(cros_ish_cl);
>> +
>> +       cros_ish_cl = ishtp_cl_allocate(cl_device);
>> +       if (!cros_ish_cl) {
>> +               up_write(&init_lock);
>> +               return;
>> +       }
>> +
>> +       ishtp_set_drvdata(cl_device, cros_ish_cl);
>> +       ishtp_set_client_data(cros_ish_cl, client_data);
>> +       client_data->cros_ish_cl = cros_ish_cl;
>> +
>> +       rv = cros_ish_init(cros_ish_cl);
>> +       if (rv) {
>> +               ishtp_cl_free(cros_ish_cl);
>> +               dev_err(cl_data_to_dev(client_data), "Reset Failed\n");
>> +               up_write(&init_lock);
>> +               return;
>> +       }
>> +
>> +       /* Refresh ec_dev device pointers */
>> +       client_data->ec_dev->priv = client_data->cros_ish_cl;
>> +       dev = cl_data_to_dev(client_data);
>> +       dev->driver_data = client_data->ec_dev;
>> +
>> +       dev_info(cl_data_to_dev(client_data), "Chrome EC ISH reset done\n");
>> +
>> +       up_write(&init_lock);
>> +}
>> +
>> +/**
>> + * cros_ec_ishtp_probe() - ISHTP client driver probe callback
>> + * @cl_device:         ISHTP client device instance
>> + *
>> + * Return: 0 for success, negative error code for failure.
>> + */
>> +static int cros_ec_ishtp_probe(struct ishtp_cl_device *cl_device)
>> +{
>> +       int rv;
>> +       struct ishtp_cl *cros_ish_cl;
>> +       struct ishtp_cl_data *client_data =
>> +               devm_kzalloc(ishtp_device(cl_device),
>> +                            sizeof(*client_data), GFP_KERNEL);
>> +       if (!client_data)
>> +               return -ENOMEM;
>> +
>> +       /* Lock for initialization to complete */
>> +       down_write(&init_lock);
>> +
>> +       cros_ish_cl = ishtp_cl_allocate(cl_device);
>> +       if (!cros_ish_cl) {
>> +               rv = -ENOMEM;
>> +               goto end_ishtp_cl_alloc_error;
>> +       }
>> +
>> +       ishtp_set_drvdata(cl_device, cros_ish_cl);
>> +       ishtp_set_client_data(cros_ish_cl, client_data);
>> +       client_data->cros_ish_cl = cros_ish_cl;
>> +       client_data->cl_device = cl_device;
>> +
>> +       init_waitqueue_head(&client_data->response.wait_queue);
>> +
>> +       INIT_WORK(&client_data->work_ishtp_reset,
>> +                 reset_handler);
>> +       INIT_WORK(&client_data->work_ec_evt,
>> +                 ish_evt_handler);
>> +
>> +       rv = cros_ish_init(cros_ish_cl);
>> +       if (rv)
>> +               goto end_ishtp_cl_init_error;
>> +
>> +       ishtp_get_device(cl_device);
>> +
>> +       up_write(&init_lock);
>> +
>> +       /* Register croc_ec_dev mfd */
>> +       rv = cros_ec_dev_init(client_data);
>> +       if (rv)
>> +               goto end_cros_ec_dev_init_error;
>> +
>> +       return 0;
>> +
>> +end_cros_ec_dev_init_error:
>> +       ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
>> +       ishtp_cl_disconnect(cros_ish_cl);
>> +       ishtp_cl_unlink(cros_ish_cl);
>> +       ishtp_cl_flush_queues(cros_ish_cl);
>> +       ishtp_put_device(cl_device);
>> +end_ishtp_cl_init_error:
>> +       ishtp_cl_free(cros_ish_cl);
>> +end_ishtp_cl_alloc_error:
>> +       up_write(&init_lock);
>> +       return rv;
>> +}
>> +
>> +/**
>> + * cros_ec_ishtp_remove() - ISHTP client driver remove callback
>> + * @cl_device:         ISHTP client device instance
>> + *
>> + * Return: 0
>> + */
>> +static int cros_ec_ishtp_remove(struct ishtp_cl_device *cl_device)
>> +{
>> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
>> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
>> +
>> +       cancel_work_sync(&client_data->work_ishtp_reset);
>> +       cancel_work_sync(&client_data->work_ec_evt);
>> +       cros_ish_deinit(cros_ish_cl);
>> +       ishtp_put_device(cl_device);
>> +
>> +       return 0;
>> +}
>> +
>> +/**
>> + * cros_ec_ishtp_reset() - ISHTP client driver reset callback
>> + * @cl_device:         ISHTP client device instance
>> + *
>> + * Return: 0
>> + */
>> +static int cros_ec_ishtp_reset(struct ishtp_cl_device *cl_device)
>> +{
>> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
>> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
>> +
>> +       schedule_work(&client_data->work_ishtp_reset);
>> +
>> +       return 0;
>> +}
>> +
>> +/**
>> + * cros_ec_ishtp_suspend() - ISHTP client driver suspend callback
>> + * @device:    device instance
>> + *
>> + * Return: 0 for success, negative error code for failure.
>> + */
>> +static int __maybe_unused cros_ec_ishtp_suspend(struct device *device)
>> +{
>> +       struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
>> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
>> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
>> +
>> +       return cros_ec_suspend(client_data->ec_dev);
>> +}
>> +
>> +/**
>> + * cros_ec_ishtp_resume() - ISHTP client driver resume callback
>> + * @device:    device instance
>> + *
>> + * Return: 0 for success, negative error code for failure.
>> + */
>> +static int __maybe_unused cros_ec_ishtp_resume(struct device *device)
>> +{
>> +       struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
>> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
>> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
>> +
>> +       return cros_ec_resume(client_data->ec_dev);
>> +}
>> +
>> +static SIMPLE_DEV_PM_OPS(cros_ec_ishtp_pm_ops, cros_ec_ishtp_suspend,
>> +                        cros_ec_ishtp_resume);
>> +
>> +static struct ishtp_cl_driver  cros_ec_ishtp_driver = {
>> +       .name = "cros_ec_ishtp",
>> +       .guid = &cros_ish_guid,
>> +       .probe = cros_ec_ishtp_probe,
>> +       .remove = cros_ec_ishtp_remove,
>> +       .reset = cros_ec_ishtp_reset,
>> +       .driver = {
>> +               .pm = &cros_ec_ishtp_pm_ops,
>> +       },
>> +};
>> +
>> +static int __init cros_ec_ishtp_mod_init(void)
>> +{
>> +       return ishtp_cl_driver_register(&cros_ec_ishtp_driver, THIS_MODULE);
>> +}
>> +
>> +static void __exit cros_ec_ishtp_mod_exit(void)
>> +{
>> +       ishtp_cl_driver_unregister(&cros_ec_ishtp_driver);
>> +}
>> +
>> +module_init(cros_ec_ishtp_mod_init);
>> +module_exit(cros_ec_ishtp_mod_exit);
>> +
>> +MODULE_DESCRIPTION("ChromeOS EC ISHTP Client Driver");
>> +MODULE_AUTHOR("Rushikesh S Kadam <rushikesh.s.kadam@intel.com>");
>> +
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_ALIAS("ishtp:*");
>> --
>> 1.9.1
>>

Re: [PATCH v3] platform: chrome: Add ChromeOS EC ISHTP driver

[Rushikesh S Kadam]

Hi Enric, Srinivas

On Thu, Apr 11, 2019 at 12:55:13PM +0200, Enric Balletbo i Serra wrote:
> Hi,
> 
> On 10/4/19 17:31, Jett Rink wrote:
> > Reviewed-by: Jett Rink <jettrink@chromium.org>
> > Tested-by: Jett Rink <jettrink@chromium.org>
> > 
> > 
> > On Sun, Apr 7, 2019 at 6:10 AM Rushikesh S Kadam
> > <rushikesh.s.kadam@intel.com> wrote:
> >>
> >> This driver implements a slim layer to enable the ChromeOS
> >> EC kernel stack (cros_ec) to communicate with ChromeOS EC
> >> firmware running on the Intel Integrated Sensor Hub (ISH).
> >>
> >> The driver registers a ChromeOS EC MFD device to connect
> >> with cros_ec kernel stack (upper layer), and it registers a
> >> client with the ISH Transport Protocol bus (lower layer) to
> >> talk with the ISH firwmare. See description of the ISHTP
> >> protocol at Documentation/hid/intel-ish-hid.txt
> >>
> >> Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
> >> ---
> >>
> >> v3
> >>  - Made several changes to improve code readability. Replaced
> >>    multiple cl_data_to_dev(client_data) with dev variable. Use
> >>    reverse Xmas tree for variable defintion where it made sense.
> >>    Dropped few debug prints. Add docstring for function
> >>    prepare_cros_ec_rx().
> >>  - Fix code in function prepare_cros_ec_rx() under label
> >>    end_cros_ec_dev_init_error.
> >>  - Recycle buffer in process_recv() on failing to obtain the
> >>    semaphore.
> >>  - Increase ISHTP TX/RX ring buffer size to 8.
> >>  - Alphabetically ordered CROS_EC_ISHTP entries in Makefile and
> >>    Kconfig.
> >>  - Updated commit message.
> >>
> >> v2
> >>  - Dropped unused "reset" parameter in function cros_ec_init()
> >>  - Change driver name to cros_ec_ishtp to be consistent with other
> >>    references in the code.
> >>  - Fixed a few typos.
> >>
> >> v1
> >>  - Initial version
> >>
> >>  drivers/platform/chrome/Kconfig         |  13 +
> >>  drivers/platform/chrome/Makefile        |   1 +
> >>  drivers/platform/chrome/cros_ec_ishtp.c | 765 ++++++++++++++++++++++++++++++++
> >>  3 files changed, 779 insertions(+)
> >>  create mode 100644 drivers/platform/chrome/cros_ec_ishtp.c
> >>
> >> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> >> index 16b1615..5848179 100644
> >> --- a/drivers/platform/chrome/Kconfig
> >> +++ b/drivers/platform/chrome/Kconfig
> >> @@ -62,6 +62,19 @@ config CROS_EC_I2C
> >>           a checksum. Failing accesses will be retried three times to
> >>           improve reliability.
> >>
> >> +config CROS_EC_ISHTP
> >> +       tristate "ChromeOS Embedded Controller (ISHTP)"
> >> +       depends on MFD_CROS_EC
> >> +       depends on INTEL_ISH_HID
> >> +       help
> >> +         If you say Y here, you get support for talking to the ChromeOS EC
> >> +         firmware running on Intel Integrated Sensor Hub (ISH), using the
> >> +         ISH Transport protocol (ISH-TP). This uses a simple byte-level
> >> +         protocol with a checksum.
> >> +
> >> +         To compile this driver as a module, choose M here: the
> >> +         module will be called cros_ec_ishtp.
> >> +
> >>  config CROS_EC_SPI
> >>         tristate "ChromeOS Embedded Controller (SPI)"
> >>         depends on MFD_CROS_EC && SPI
> >> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> >> index cd591bf..4efe102 100644
> >> --- a/drivers/platform/chrome/Makefile
> >> +++ b/drivers/platform/chrome/Makefile
> >> @@ -7,6 +7,7 @@ cros_ec_ctl-objs                        := cros_ec_sysfs.o cros_ec_lightbar.o \
> >>                                            cros_ec_vbc.o cros_ec_debugfs.o
> >>  obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
> >>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
> >> +obj-$(CONFIG_CROS_EC_ISHTP)            += cros_ec_ishtp.o
> >>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
> >>  cros_ec_lpcs-objs                      := cros_ec_lpc.o cros_ec_lpc_reg.o
> >>  cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC) += cros_ec_lpc_mec.o
> >> diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c
> >> new file mode 100644
> >> index 0000000..b1d19c4
> >> --- /dev/null
> >> +++ b/drivers/platform/chrome/cros_ec_ishtp.c
> >> @@ -0,0 +1,765 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +/*
> >> + * ISHTP client driver for talking to the Chrome OS EC firmware running
> >> + * on Intel Integrated Sensor Hub (ISH) using the ISH Transport protocol
> >> + * (ISH-TP).
> >> + *
> >> + * Copyright (c) 2019, Intel Corporation.
> >> + */
> >> +
> >> +#include <linux/delay.h>
> >> +#include <linux/mfd/core.h>
> >> +#include <linux/mfd/cros_ec.h>
> >> +#include <linux/mfd/cros_ec_commands.h>
> >> +#include <linux/module.h>
> >> +#include <linux/pci.h>
> >> +#include <linux/intel-ish-client-if.h>
> >> +
> 
> I think that this patch depends on another patchset that's in linux-next but
> diddn't land yet to mainline. Do you know if the dependencies are queued for
> next merge window? Can you provide the exact patches that this patch depends on?

Enric, 
Sorry I missed mentioning this. 
 
The patch have dependency on intel-ish-hid stack on hid git tree,
branch for-5.2/ish
https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git/log/?h=for-5.2/ish

Srinivas, 
Could you tell if the patches are queued for next merge window?

Thanks
Rushikesh


> 
> Thanks,
>  Enric
> 
> 
> >> +/*
> >> + * ISH TX/RX ring buffer pool size
> >> + *
> >> + * The AP->ISH messages and corresponding ISH->AP responses are
> >> + * serialized. We need 1 TX and 1 RX buffer for these.
> >> + *
> >> + * The MKBP ISH->AP events are serialized. We need one additional RX
> >> + * buffer for them.
> >> + */
> >> +#define CROS_ISH_CL_TX_RING_SIZE               8
> >> +#define CROS_ISH_CL_RX_RING_SIZE               8
> >> +
> >> +/* ISH CrOS EC Host Commands */
> >> +enum cros_ec_ish_channel {
> >> +       CROS_EC_COMMAND = 1,                    /* AP->ISH message */
> >> +       CROS_MKBP_EVENT = 2,                    /* ISH->AP events */
> >> +};
> >> +
> >> +/*
> >> + * ISH firmware timeout for 1 message send failure is 1Hz, and the
> >> + * firmware will retry 2 times, so 3Hz is used for timeout.
> >> + */
> >> +#define ISHTP_SEND_TIMEOUT                     (3 * HZ)
> >> +
> >> +/* ISH Transport CrOS EC ISH client unique GUID */
> >> +static const guid_t cros_ish_guid =
> >> +       GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
> >> +                 0xb0, 0xd8, 0x9e, 0x7c, 0xda, 0xe0, 0xd6, 0xa0);
> >> +
> >> +struct header {
> >> +       u8 channel;
> >> +       u8 status;
> >> +       u8 reserved[2];
> >> +} __packed;
> >> +
> >> +struct cros_ish_out_msg {
> >> +       struct header hdr;
> >> +       struct ec_host_request ec_request;
> >> +} __packed;
> >> +
> >> +struct cros_ish_in_msg {
> >> +       struct header hdr;
> >> +       struct ec_host_response ec_response;
> >> +} __packed;
> >> +
> >> +#define IN_MSG_EC_RESPONSE_PREAMBLE                                    \
> >> +       offsetof(struct cros_ish_in_msg, ec_response)
> >> +
> >> +#define OUT_MSG_EC_REQUEST_PREAMBLE                                    \
> >> +       offsetof(struct cros_ish_out_msg, ec_request)
> >> +
> >> +#define cl_data_to_dev(client_data) ishtp_device((client_data)->cl_device)
> >> +
> >> +/*
> >> + * The Read-Write Semaphore is used to prevent message TX or RX while
> >> + * the ishtp client is being initialized or undergoing reset.
> >> + *
> >> + * The readers are the kernel function calls responsible for IA->ISH
> >> + * and ISH->AP messaging.
> >> + *
> >> + * The writers are .reset() and .probe() function.
> >> + */
> >> +DECLARE_RWSEM(init_lock);
> >> +
> >> +/**
> >> + * struct response_info - Encapsulate firmware response related
> >> + *                     information for passing between function
> >> + *                     ish_send() and process_recv() callback.
> >> + * @data:              Copy the data received from firmware here.
> >> + * @max_size:          Max size allocated for the @data buffer. If the
> >> + *                     received data exceeds this value, we log an
> >> + *                     error.
> >> + * @size:              Actual size of data received from firmware.
> >> + * @error:             0 for success, negative error code for a
> >> + *                     failure in function process_recv().
> >> + * @received:          Set to true on receiving a valid firmware
> >> + *                     response to host command
> >> + * @wait_queue:                Wait queue for Host firmware loading where the
> >> + *                     client sends message to ISH firmware and waits
> >> + *                     for response
> >> + */
> >> +struct response_info {
> >> +       void *data;
> >> +       size_t max_size;
> >> +       size_t size;
> >> +       int error;
> >> +       bool received;
> >> +       wait_queue_head_t wait_queue;
> >> +};
> >> +
> >> +/**
> >> + * struct ishtp_cl_data - Encapsulate per ISH TP Client.
> >> + * @cros_ish_cl:       ISHTP firmware client instance.
> >> + * @cl_device:         ISHTP client device instance.
> >> + * @response:          Firmware response information for passing
> >> + *                     between function ish_send() and process_recv()
> >> + *                     callback.
> >> + * @work_ishtp_reset:  Work queue reset handling.
> >> + * @work_ec_evt:       Work queue for EC events.
> >> + * @ec_dev:            CrOS EC MFD device.
> >> + *
> >> + * This structure is used to store per client data.
> >> + */
> >> +struct ishtp_cl_data {
> >> +       struct ishtp_cl *cros_ish_cl;
> >> +       struct ishtp_cl_device *cl_device;
> >> +
> >> +       /*
> >> +        * Used for passing firmware response information between
> >> +        * ish_send() and process_recv() callback.
> >> +        */
> >> +       struct response_info response;
> >> +
> >> +       struct work_struct work_ishtp_reset;
> >> +       struct work_struct work_ec_evt;
> >> +       struct cros_ec_device *ec_dev;
> >> +};
> >> +
> >> +/**
> >> + * ish_evt_handler - ISH to AP event handler
> >> + * @work:              Work struct
> >> + */
> >> +static void ish_evt_handler(struct work_struct *work)
> >> +{
> >> +       struct ishtp_cl_data *client_data =
> >> +               container_of(work, struct ishtp_cl_data, work_ec_evt);
> >> +       struct cros_ec_device *ec_dev = client_data->ec_dev;
> >> +
> >> +       if (cros_ec_get_next_event(ec_dev, NULL) > 0) {
> >> +               blocking_notifier_call_chain(&ec_dev->event_notifier,
> >> +                                            0, ec_dev);
> >> +       }
> >> +}
> >> +
> >> +/**
> >> + * ish_send() - Send message from host to firmware
> >> + * @client_data:       Client data instance
> >> + * @out_msg:           Message buffer to be sent to firmware
> >> + * @out_size:          Size of out going message
> >> + * @in_msg:            Message buffer where the incoming data copied.
> >> + *                     This buffer is allocated by calling
> >> + * @in_size:           Max size of incoming message
> >> + *
> >> + * Return: Number of bytes copied in the in_msg on success, negative
> >> + * error code on failure.
> >> + */
> >> +static int ish_send(struct ishtp_cl_data *client_data,
> >> +                   u8 *out_msg, size_t out_size,
> >> +                   u8 *in_msg, size_t in_size)
> >> +{
> >> +       int rv;
> >> +       struct header *out_hdr = (struct header *)out_msg;
> >> +       struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl;
> >> +
> >> +       dev_dbg(cl_data_to_dev(client_data),
> >> +               "%s: channel=%02u status=%02u\n",
> >> +               __func__, out_hdr->channel, out_hdr->status);
> >> +
> >> +       /* Setup for incoming response */
> >> +       client_data->response.data = in_msg;
> >> +       client_data->response.max_size = in_size;
> >> +       client_data->response.error = 0;
> >> +       client_data->response.received = false;
> >> +
> >> +       rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
> >> +       if (rv) {
> >> +               dev_err(cl_data_to_dev(client_data),
> >> +                       "ishtp_cl_send error %d\n", rv);
> >> +               return rv;
> >> +       }
> >> +
> >> +       wait_event_interruptible_timeout(client_data->response.wait_queue,
> >> +                                        client_data->response.received,
> >> +                                        ISHTP_SEND_TIMEOUT);
> >> +       if (!client_data->response.received) {
> >> +               dev_err(cl_data_to_dev(client_data),
> >> +                       "Timed out for response to host message\n");
> >> +               return -ETIMEDOUT;
> >> +       }
> >> +
> >> +       if (client_data->response.error < 0)
> >> +               return client_data->response.error;
> >> +
> >> +       return client_data->response.size;
> >> +}
> >> +
> >> +/**
> >> + * process_recv() -    Received and parse incoming packet
> >> + * @cros_ish_cl:       Client instance to get stats
> >> + * @rb_in_proc:                Host interface message buffer
> >> + *
> >> + * Parse the incoming packet. If it is a response packet then it will
> >> + * update per instance flags and wake up the caller waiting to for the
> >> + * response. If it is an event packet then it will schedule event work.
> >> + */
> >> +static void process_recv(struct ishtp_cl *cros_ish_cl,
> >> +                        struct ishtp_cl_rb *rb_in_proc)
> >> +{
> >> +       size_t data_len = rb_in_proc->buf_idx;
> >> +       struct ishtp_cl_data *client_data =
> >> +               ishtp_get_client_data(cros_ish_cl);
> >> +       struct device *dev = cl_data_to_dev(client_data);
> >> +       struct cros_ish_in_msg *in_msg =
> >> +               (struct cros_ish_in_msg *)rb_in_proc->buffer.data;
> >> +
> >> +       /* Proceed only if reset or init is not in progress */
> >> +       if (!down_read_trylock(&init_lock)) {
> >> +               /* Free the buffer */
> >> +               ishtp_cl_io_rb_recycle(rb_in_proc);
> >> +               dev_warn(dev,
> >> +                        "Host is not ready to receive incoming messages\n");
> >> +               return;
> >> +       }
> >> +
> >> +       /*
> >> +        * All firmware messages contain a header. Check the buffer size
> >> +        * before accessing elements inside.
> >> +        */
> >> +       if (!rb_in_proc->buffer.data) {
> >> +               dev_warn(dev, "rb_in_proc->buffer.data returned null");
> >> +               client_data->response.error = -EBADMSG;
> >> +               goto end_error;
> >> +       }
> >> +
> >> +       if (data_len < sizeof(struct header)) {
> >> +               dev_err(dev, "data size %zu is less than header %zu\n",
> >> +                       data_len, sizeof(struct header));
> >> +               client_data->response.error = -EMSGSIZE;
> >> +               goto end_error;
> >> +       }
> >> +
> >> +       dev_dbg(dev, "channel=%02u status=%02u\n",
> >> +               in_msg->hdr.channel, in_msg->hdr.status);
> >> +
> >> +       switch (in_msg->hdr.channel) {
> >> +       case CROS_EC_COMMAND:
> >> +               /* Sanity check */
> >> +               if (!client_data->response.data) {
> >> +                       dev_err(dev,
> >> +                               "Receiving buffer is null. Should be allocated by calling function\n");
> >> +                       client_data->response.error = -EINVAL;
> >> +                       goto error_wake_up;
> >> +               }
> >> +
> >> +               if (client_data->response.received) {
> >> +                       dev_err(dev,
> >> +                               "Previous firmware message not yet processed\n");
> >> +                       client_data->response.error = -EINVAL;
> >> +                       goto error_wake_up;
> >> +               }
> >> +
> >> +               if (data_len > client_data->response.max_size) {
> >> +                       dev_err(dev,
> >> +                               "Received buffer size %zu is larger than allocated buffer %zu\n",
> >> +                               data_len, client_data->response.max_size);
> >> +                       client_data->response.error = -EMSGSIZE;
> >> +                       goto error_wake_up;
> >> +               }
> >> +
> >> +               if (in_msg->hdr.status) {
> >> +                       dev_err(dev, "firmware returned status %d\n",
> >> +                               in_msg->hdr.status);
> >> +                       client_data->response.error = -EIO;
> >> +                       goto error_wake_up;
> >> +               }
> >> +
> >> +               /* Update the actual received buffer size */
> >> +               client_data->response.size = data_len;
> >> +
> >> +               /*
> >> +                * Copy the buffer received in firmware response for the
> >> +                * calling thread.
> >> +                */
> >> +               memcpy(client_data->response.data,
> >> +                      rb_in_proc->buffer.data, data_len);
> >> +
> >> +               /* Set flag before waking up the caller */
> >> +               client_data->response.received = true;
> >> +error_wake_up:
> >> +               /* Wake the calling thread */
> >> +               wake_up_interruptible(&client_data->response.wait_queue);
> >> +
> >> +               break;
> >> +
> >> +       case CROS_MKBP_EVENT:
> >> +               /* The event system doesn't send any data in buffer */
> >> +               schedule_work(&client_data->work_ec_evt);
> >> +
> >> +               break;
> >> +
> >> +       default:
> >> +               dev_err(dev, "Invalid channel=%02d\n", in_msg->hdr.channel);
> >> +       }
> >> +
> >> +end_error:
> >> +       /* Free the buffer */
> >> +       ishtp_cl_io_rb_recycle(rb_in_proc);
> >> +
> >> +       up_read(&init_lock);
> >> +}
> >> +
> >> +/**
> >> + * ish_event_cb() - bus driver callback for incoming message
> >> + * @cl_device:         ISHTP client device for which this message is
> >> + *                     targeted.
> >> + *
> >> + * Remove the packet from the list and process the message by calling
> >> + * process_recv.
> >> + */
> >> +static void ish_event_cb(struct ishtp_cl_device *cl_device)
> >> +{
> >> +       struct ishtp_cl_rb *rb_in_proc;
> >> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> >> +
> >> +       while ((rb_in_proc = ishtp_cl_rx_get_rb(cros_ish_cl)) != NULL) {
> >> +               /* Decide what to do with received data */
> >> +               process_recv(cros_ish_cl, rb_in_proc);
> >> +       }
> >> +}
> >> +
> >> +/**
> >> + * cros_ish_init() - Init function for ISHTP client
> >> + * @cros_ish_cl:       ISHTP client instance
> >> + *
> >> + * This function complete the initializtion of the client.
> >> + *
> >> + * Return: 0 for success, negative error code for failure.
> >> + */
> >> +static int cros_ish_init(struct ishtp_cl *cros_ish_cl)
> >> +{
> >> +       int rv;
> >> +       struct ishtp_device *dev;
> >> +       struct ishtp_fw_client *fw_client;
> >> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> >> +
> >> +       rv = ishtp_cl_link(cros_ish_cl);
> >> +       if (rv) {
> >> +               dev_err(cl_data_to_dev(client_data),
> >> +                       "ishtp_cl_link failed\n");
> >> +               return rv;
> >> +       }
> >> +
> >> +       dev = ishtp_get_ishtp_device(cros_ish_cl);
> >> +
> >> +       /* Connect to firmware client */
> >> +       ishtp_set_tx_ring_size(cros_ish_cl, CROS_ISH_CL_TX_RING_SIZE);
> >> +       ishtp_set_rx_ring_size(cros_ish_cl, CROS_ISH_CL_RX_RING_SIZE);
> >> +
> >> +       fw_client = ishtp_fw_cl_get_client(dev, &cros_ish_guid);
> >> +       if (!fw_client) {
> >> +               dev_err(cl_data_to_dev(client_data),
> >> +                       "ish client uuid not found\n");
> >> +               rv = -ENOENT;
> >> +               goto err_cl_unlink;
> >> +       }
> >> +
> >> +       ishtp_cl_set_fw_client_id(cros_ish_cl,
> >> +                                 ishtp_get_fw_client_id(fw_client));
> >> +       ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_CONNECTING);
> >> +
> >> +       rv = ishtp_cl_connect(cros_ish_cl);
> >> +       if (rv) {
> >> +               dev_err(cl_data_to_dev(client_data),
> >> +                       "client connect fail\n");
> >> +               goto err_cl_unlink;
> >> +       }
> >> +
> >> +       ishtp_register_event_cb(client_data->cl_device, ish_event_cb);
> >> +       return 0;
> >> +
> >> +err_cl_unlink:
> >> +       ishtp_cl_unlink(cros_ish_cl);
> >> +       return rv;
> >> +}
> >> +
> >> +/**
> >> + * cros_ish_deinit() - Deinit function for ISHTP client
> >> + * @cros_ish_cl:       ISHTP client instance
> >> + *
> >> + * Unlink and free cros_ec client
> >> + */
> >> +static void cros_ish_deinit(struct ishtp_cl *cros_ish_cl)
> >> +{
> >> +       ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
> >> +       ishtp_cl_disconnect(cros_ish_cl);
> >> +       ishtp_cl_unlink(cros_ish_cl);
> >> +       ishtp_cl_flush_queues(cros_ish_cl);
> >> +
> >> +       /* Disband and free all Tx and Rx client-level rings */
> >> +       ishtp_cl_free(cros_ish_cl);
> >> +}
> >> +
> >> +/**
> >> + * prepare_cros_ec_rx() - Check & prepare receive buffer
> >> + * @in_msg:            Incoming message buffer
> >> + * @cros_ec_command    cros_ec command used to send & receive data
> >> + *
> >> + * Check the received buffer. Convert to cros_ec_command format.
> >> + */
> >> +static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
> >> +                             const struct cros_ish_in_msg *in_msg,
> >> +                             struct cros_ec_command *msg)
> >> +{
> >> +       u8 sum = 0;
> >> +       int i, rv, offset;
> >> +
> >> +       /* Check response error code */
> >> +       msg->result = in_msg->ec_response.result;
> >> +       rv = cros_ec_check_result(ec_dev, msg);
> >> +       if (rv < 0)
> >> +               return rv;
> >> +
> >> +       if (in_msg->ec_response.data_len > msg->insize) {
> >> +               dev_err(ec_dev->dev, "Packet too long (%d bytes, expected %d)",
> >> +                       in_msg->ec_response.data_len, msg->insize);
> >> +               return -ENOSPC;
> >> +       }
> >> +
> >> +       /* Copy response packet payload and compute checksum */
> >> +       for (i = 0; i < sizeof(struct ec_host_response); i++)
> >> +               sum += ((u8 *)in_msg)[IN_MSG_EC_RESPONSE_PREAMBLE + i];
> >> +
> >> +       offset = sizeof(struct cros_ish_in_msg);
> >> +       for (i = 0; i < in_msg->ec_response.data_len; i++)
> >> +               sum += msg->data[i] = ((u8 *)in_msg)[offset + i];
> >> +
> >> +       if (sum) {
> >> +               dev_dbg(ec_dev->dev, "Bad received packet checksum %d\n", sum);
> >> +               return -EBADMSG;
> >> +       }
> >> +
> >> +       return 0;
> >> +}
> >> +
> >> +static int cros_ec_pkt_xfer_ish(struct cros_ec_device *ec_dev,
> >> +                               struct cros_ec_command *msg)
> >> +{
> >> +       int rv;
> >> +       struct ishtp_cl *cros_ish_cl = ec_dev->priv;
> >> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> >> +       struct device *dev = cl_data_to_dev(client_data);
> >> +       struct cros_ish_in_msg *in_msg = (struct cros_ish_in_msg *)ec_dev->din;
> >> +       struct cros_ish_out_msg *out_msg =
> >> +               (struct cros_ish_out_msg *)ec_dev->dout;
> >> +       size_t in_size = sizeof(struct cros_ish_in_msg) + msg->insize;
> >> +       size_t out_size = sizeof(struct cros_ish_out_msg) + msg->outsize;
> >> +
> >> +       /* Proceed only if reset-init is not in progress */
> >> +       if (!down_read_trylock(&init_lock)) {
> >> +               dev_warn(dev,
> >> +                        "Host is not ready to send messages to ISH. Try again\n");
> >> +               return -EAGAIN;
> >> +       }
> >> +
> >> +       /* Sanity checks */
> >> +       if (in_size > ec_dev->din_size) {
> >> +               dev_err(dev,
> >> +                       "Incoming payload size %zu is too large for ec_dev->din_size %d\n",
> >> +                       in_size, ec_dev->din_size);
> >> +               return -EMSGSIZE;
> >> +       }
> >> +
> >> +       if (out_size > ec_dev->dout_size) {
> >> +               dev_err(dev,
> >> +                       "Outgoing payload size %zu is too large for ec_dev->dout_size %d\n",
> >> +                       out_size, ec_dev->dout_size);
> >> +               return -EMSGSIZE;
> >> +       }
> >> +
> >> +       /* Prepare the package to be sent over ISH TP */
> >> +       out_msg->hdr.channel = CROS_EC_COMMAND;
> >> +       out_msg->hdr.status = 0;
> >> +
> >> +       ec_dev->dout += OUT_MSG_EC_REQUEST_PREAMBLE;
> >> +       cros_ec_prepare_tx(ec_dev, msg);
> >> +       ec_dev->dout -= OUT_MSG_EC_REQUEST_PREAMBLE;
> >> +
> >> +       dev_dbg(dev,
> >> +               "out_msg: struct_ver=0x%x checksum=0x%x command=0x%x command_ver=0x%x data_len=0x%x\n",
> >> +               out_msg->ec_request.struct_version,
> >> +               out_msg->ec_request.checksum,
> >> +               out_msg->ec_request.command,
> >> +               out_msg->ec_request.command_version,
> >> +               out_msg->ec_request.data_len);
> >> +
> >> +       /* Send command to ISH EC firmware and read response */
> >> +       rv = ish_send(client_data,
> >> +                     (u8 *)out_msg, out_size,
> >> +                     (u8 *)in_msg, in_size);
> >> +       if (rv < 0)
> >> +               goto end_error;
> >> +
> >> +       rv = prepare_cros_ec_rx(ec_dev, in_msg, msg);
> >> +       if (rv)
> >> +               goto end_error;
> >> +
> >> +       rv = in_msg->ec_response.data_len;
> >> +
> >> +       dev_dbg(dev,
> >> +               "in_msg: struct_ver=0x%x checksum=0x%x result=0x%x data_len=0x%x\n",
> >> +               in_msg->ec_response.struct_version,
> >> +               in_msg->ec_response.checksum,
> >> +               in_msg->ec_response.result,
> >> +               in_msg->ec_response.data_len);
> >> +
> >> +end_error:
> >> +       if (msg->command == EC_CMD_REBOOT_EC)
> >> +               msleep(EC_REBOOT_DELAY_MS);
> >> +
> >> +       up_read(&init_lock);
> >> +
> >> +       return rv;
> >> +}
> >> +
> >> +static int cros_ec_dev_init(struct ishtp_cl_data *client_data)
> >> +{
> >> +       struct cros_ec_device *ec_dev;
> >> +       struct device *dev = cl_data_to_dev(client_data);
> >> +
> >> +       ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
> >> +       if (!ec_dev)
> >> +               return -ENOMEM;
> >> +
> >> +       client_data->ec_dev = ec_dev;
> >> +       dev->driver_data = ec_dev;
> >> +
> >> +       ec_dev->dev = dev;
> >> +       ec_dev->priv = client_data->cros_ish_cl;
> >> +       ec_dev->cmd_xfer = NULL;
> >> +       ec_dev->pkt_xfer = cros_ec_pkt_xfer_ish;
> >> +       ec_dev->phys_name = dev_name(dev);
> >> +       ec_dev->din_size = sizeof(struct cros_ish_in_msg) +
> >> +                          sizeof(struct ec_response_get_protocol_info);
> >> +       ec_dev->dout_size = sizeof(struct cros_ish_out_msg);
> >> +
> >> +       return cros_ec_register(ec_dev);
> >> +}
> >> +
> >> +static void reset_handler(struct work_struct *work)
> >> +{
> >> +       int rv;
> >> +       struct device *dev;
> >> +       struct ishtp_cl *cros_ish_cl;
> >> +       struct ishtp_cl_device *cl_device;
> >> +       struct ishtp_cl_data *client_data =
> >> +               container_of(work, struct ishtp_cl_data, work_ishtp_reset);
> >> +
> >> +       /* Lock for reset to complete */
> >> +       down_write(&init_lock);
> >> +
> >> +       cros_ish_cl = client_data->cros_ish_cl;
> >> +       cl_device = client_data->cl_device;
> >> +
> >> +       /* Unlink, flush queues & start again */
> >> +       ishtp_cl_unlink(cros_ish_cl);
> >> +       ishtp_cl_flush_queues(cros_ish_cl);
> >> +       ishtp_cl_free(cros_ish_cl);
> >> +
> >> +       cros_ish_cl = ishtp_cl_allocate(cl_device);
> >> +       if (!cros_ish_cl) {
> >> +               up_write(&init_lock);
> >> +               return;
> >> +       }
> >> +
> >> +       ishtp_set_drvdata(cl_device, cros_ish_cl);
> >> +       ishtp_set_client_data(cros_ish_cl, client_data);
> >> +       client_data->cros_ish_cl = cros_ish_cl;
> >> +
> >> +       rv = cros_ish_init(cros_ish_cl);
> >> +       if (rv) {
> >> +               ishtp_cl_free(cros_ish_cl);
> >> +               dev_err(cl_data_to_dev(client_data), "Reset Failed\n");
> >> +               up_write(&init_lock);
> >> +               return;
> >> +       }
> >> +
> >> +       /* Refresh ec_dev device pointers */
> >> +       client_data->ec_dev->priv = client_data->cros_ish_cl;
> >> +       dev = cl_data_to_dev(client_data);
> >> +       dev->driver_data = client_data->ec_dev;
> >> +
> >> +       dev_info(cl_data_to_dev(client_data), "Chrome EC ISH reset done\n");
> >> +
> >> +       up_write(&init_lock);
> >> +}
> >> +
> >> +/**
> >> + * cros_ec_ishtp_probe() - ISHTP client driver probe callback
> >> + * @cl_device:         ISHTP client device instance
> >> + *
> >> + * Return: 0 for success, negative error code for failure.
> >> + */
> >> +static int cros_ec_ishtp_probe(struct ishtp_cl_device *cl_device)
> >> +{
> >> +       int rv;
> >> +       struct ishtp_cl *cros_ish_cl;
> >> +       struct ishtp_cl_data *client_data =
> >> +               devm_kzalloc(ishtp_device(cl_device),
> >> +                            sizeof(*client_data), GFP_KERNEL);
> >> +       if (!client_data)
> >> +               return -ENOMEM;
> >> +
> >> +       /* Lock for initialization to complete */
> >> +       down_write(&init_lock);
> >> +
> >> +       cros_ish_cl = ishtp_cl_allocate(cl_device);
> >> +       if (!cros_ish_cl) {
> >> +               rv = -ENOMEM;
> >> +               goto end_ishtp_cl_alloc_error;
> >> +       }
> >> +
> >> +       ishtp_set_drvdata(cl_device, cros_ish_cl);
> >> +       ishtp_set_client_data(cros_ish_cl, client_data);
> >> +       client_data->cros_ish_cl = cros_ish_cl;
> >> +       client_data->cl_device = cl_device;
> >> +
> >> +       init_waitqueue_head(&client_data->response.wait_queue);
> >> +
> >> +       INIT_WORK(&client_data->work_ishtp_reset,
> >> +                 reset_handler);
> >> +       INIT_WORK(&client_data->work_ec_evt,
> >> +                 ish_evt_handler);
> >> +
> >> +       rv = cros_ish_init(cros_ish_cl);
> >> +       if (rv)
> >> +               goto end_ishtp_cl_init_error;
> >> +
> >> +       ishtp_get_device(cl_device);
> >> +
> >> +       up_write(&init_lock);
> >> +
> >> +       /* Register croc_ec_dev mfd */
> >> +       rv = cros_ec_dev_init(client_data);
> >> +       if (rv)
> >> +               goto end_cros_ec_dev_init_error;
> >> +
> >> +       return 0;
> >> +
> >> +end_cros_ec_dev_init_error:
> >> +       ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
> >> +       ishtp_cl_disconnect(cros_ish_cl);
> >> +       ishtp_cl_unlink(cros_ish_cl);
> >> +       ishtp_cl_flush_queues(cros_ish_cl);
> >> +       ishtp_put_device(cl_device);
> >> +end_ishtp_cl_init_error:
> >> +       ishtp_cl_free(cros_ish_cl);
> >> +end_ishtp_cl_alloc_error:
> >> +       up_write(&init_lock);
> >> +       return rv;
> >> +}
> >> +
> >> +/**
> >> + * cros_ec_ishtp_remove() - ISHTP client driver remove callback
> >> + * @cl_device:         ISHTP client device instance
> >> + *
> >> + * Return: 0
> >> + */
> >> +static int cros_ec_ishtp_remove(struct ishtp_cl_device *cl_device)
> >> +{
> >> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> >> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> >> +
> >> +       cancel_work_sync(&client_data->work_ishtp_reset);
> >> +       cancel_work_sync(&client_data->work_ec_evt);
> >> +       cros_ish_deinit(cros_ish_cl);
> >> +       ishtp_put_device(cl_device);
> >> +
> >> +       return 0;
> >> +}
> >> +
> >> +/**
> >> + * cros_ec_ishtp_reset() - ISHTP client driver reset callback
> >> + * @cl_device:         ISHTP client device instance
> >> + *
> >> + * Return: 0
> >> + */
> >> +static int cros_ec_ishtp_reset(struct ishtp_cl_device *cl_device)
> >> +{
> >> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> >> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> >> +
> >> +       schedule_work(&client_data->work_ishtp_reset);
> >> +
> >> +       return 0;
> >> +}
> >> +
> >> +/**
> >> + * cros_ec_ishtp_suspend() - ISHTP client driver suspend callback
> >> + * @device:    device instance
> >> + *
> >> + * Return: 0 for success, negative error code for failure.
> >> + */
> >> +static int __maybe_unused cros_ec_ishtp_suspend(struct device *device)
> >> +{
> >> +       struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> >> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> >> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> >> +
> >> +       return cros_ec_suspend(client_data->ec_dev);
> >> +}
> >> +
> >> +/**
> >> + * cros_ec_ishtp_resume() - ISHTP client driver resume callback
> >> + * @device:    device instance
> >> + *
> >> + * Return: 0 for success, negative error code for failure.
> >> + */
> >> +static int __maybe_unused cros_ec_ishtp_resume(struct device *device)
> >> +{
> >> +       struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> >> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> >> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> >> +
> >> +       return cros_ec_resume(client_data->ec_dev);
> >> +}
> >> +
> >> +static SIMPLE_DEV_PM_OPS(cros_ec_ishtp_pm_ops, cros_ec_ishtp_suspend,
> >> +                        cros_ec_ishtp_resume);
> >> +
> >> +static struct ishtp_cl_driver  cros_ec_ishtp_driver = {
> >> +       .name = "cros_ec_ishtp",
> >> +       .guid = &cros_ish_guid,
> >> +       .probe = cros_ec_ishtp_probe,
> >> +       .remove = cros_ec_ishtp_remove,
> >> +       .reset = cros_ec_ishtp_reset,
> >> +       .driver = {
> >> +               .pm = &cros_ec_ishtp_pm_ops,
> >> +       },
> >> +};
> >> +
> >> +static int __init cros_ec_ishtp_mod_init(void)
> >> +{
> >> +       return ishtp_cl_driver_register(&cros_ec_ishtp_driver, THIS_MODULE);
> >> +}
> >> +
> >> +static void __exit cros_ec_ishtp_mod_exit(void)
> >> +{
> >> +       ishtp_cl_driver_unregister(&cros_ec_ishtp_driver);
> >> +}
> >> +
> >> +module_init(cros_ec_ishtp_mod_init);
> >> +module_exit(cros_ec_ishtp_mod_exit);
> >> +
> >> +MODULE_DESCRIPTION("ChromeOS EC ISHTP Client Driver");
> >> +MODULE_AUTHOR("Rushikesh S Kadam <rushikesh.s.kadam@intel.com>");
> >> +
> >> +MODULE_LICENSE("GPL v2");
> >> +MODULE_ALIAS("ishtp:*");
> >> --
> >> 1.9.1
> >>

-- 

Re: [PATCH v3] platform: chrome: Add ChromeOS EC ISHTP driver

[Enric Balletbo i Serra]

Hi,

On 11/4/19 13:10, Rushikesh S Kadam wrote:
> Hi Enric, Srinivas
> 
> On Thu, Apr 11, 2019 at 12:55:13PM +0200, Enric Balletbo i Serra wrote:
>> Hi,
>>
>> On 10/4/19 17:31, Jett Rink wrote:
>>> Reviewed-by: Jett Rink <jettrink@chromium.org>
>>> Tested-by: Jett Rink <jettrink@chromium.org>
>>>
>>>
>>> On Sun, Apr 7, 2019 at 6:10 AM Rushikesh S Kadam
>>> <rushikesh.s.kadam@intel.com> wrote:
>>>>
>>>> This driver implements a slim layer to enable the ChromeOS
>>>> EC kernel stack (cros_ec) to communicate with ChromeOS EC
>>>> firmware running on the Intel Integrated Sensor Hub (ISH).
>>>>
>>>> The driver registers a ChromeOS EC MFD device to connect
>>>> with cros_ec kernel stack (upper layer), and it registers a
>>>> client with the ISH Transport Protocol bus (lower layer) to
>>>> talk with the ISH firwmare. See description of the ISHTP
>>>> protocol at Documentation/hid/intel-ish-hid.txt
>>>>
>>>> Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
>>>> ---
>>>>
>>>> v3
>>>>  - Made several changes to improve code readability. Replaced
>>>>    multiple cl_data_to_dev(client_data) with dev variable. Use
>>>>    reverse Xmas tree for variable defintion where it made sense.
>>>>    Dropped few debug prints. Add docstring for function
>>>>    prepare_cros_ec_rx().
>>>>  - Fix code in function prepare_cros_ec_rx() under label
>>>>    end_cros_ec_dev_init_error.
>>>>  - Recycle buffer in process_recv() on failing to obtain the
>>>>    semaphore.
>>>>  - Increase ISHTP TX/RX ring buffer size to 8.
>>>>  - Alphabetically ordered CROS_EC_ISHTP entries in Makefile and
>>>>    Kconfig.
>>>>  - Updated commit message.
>>>>
>>>> v2
>>>>  - Dropped unused "reset" parameter in function cros_ec_init()
>>>>  - Change driver name to cros_ec_ishtp to be consistent with other
>>>>    references in the code.
>>>>  - Fixed a few typos.
>>>>
>>>> v1
>>>>  - Initial version
>>>>
>>>>  drivers/platform/chrome/Kconfig         |  13 +
>>>>  drivers/platform/chrome/Makefile        |   1 +
>>>>  drivers/platform/chrome/cros_ec_ishtp.c | 765 ++++++++++++++++++++++++++++++++
>>>>  3 files changed, 779 insertions(+)
>>>>  create mode 100644 drivers/platform/chrome/cros_ec_ishtp.c
>>>>
>>>> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
>>>> index 16b1615..5848179 100644
>>>> --- a/drivers/platform/chrome/Kconfig
>>>> +++ b/drivers/platform/chrome/Kconfig
>>>> @@ -62,6 +62,19 @@ config CROS_EC_I2C
>>>>           a checksum. Failing accesses will be retried three times to
>>>>           improve reliability.
>>>>
>>>> +config CROS_EC_ISHTP
>>>> +       tristate "ChromeOS Embedded Controller (ISHTP)"
>>>> +       depends on MFD_CROS_EC
>>>> +       depends on INTEL_ISH_HID
>>>> +       help
>>>> +         If you say Y here, you get support for talking to the ChromeOS EC
>>>> +         firmware running on Intel Integrated Sensor Hub (ISH), using the
>>>> +         ISH Transport protocol (ISH-TP). This uses a simple byte-level
>>>> +         protocol with a checksum.
>>>> +
>>>> +         To compile this driver as a module, choose M here: the
>>>> +         module will be called cros_ec_ishtp.
>>>> +
>>>>  config CROS_EC_SPI
>>>>         tristate "ChromeOS Embedded Controller (SPI)"
>>>>         depends on MFD_CROS_EC && SPI
>>>> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
>>>> index cd591bf..4efe102 100644
>>>> --- a/drivers/platform/chrome/Makefile
>>>> +++ b/drivers/platform/chrome/Makefile
>>>> @@ -7,6 +7,7 @@ cros_ec_ctl-objs                        := cros_ec_sysfs.o cros_ec_lightbar.o \
>>>>                                            cros_ec_vbc.o cros_ec_debugfs.o
>>>>  obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
>>>>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
>>>> +obj-$(CONFIG_CROS_EC_ISHTP)            += cros_ec_ishtp.o
>>>>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
>>>>  cros_ec_lpcs-objs                      := cros_ec_lpc.o cros_ec_lpc_reg.o
>>>>  cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC) += cros_ec_lpc_mec.o
>>>> diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c
>>>> new file mode 100644
>>>> index 0000000..b1d19c4
>>>> --- /dev/null
>>>> +++ b/drivers/platform/chrome/cros_ec_ishtp.c
>>>> @@ -0,0 +1,765 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +/*
>>>> + * ISHTP client driver for talking to the Chrome OS EC firmware running
>>>> + * on Intel Integrated Sensor Hub (ISH) using the ISH Transport protocol
>>>> + * (ISH-TP).
>>>> + *
>>>> + * Copyright (c) 2019, Intel Corporation.
>>>> + */
>>>> +
>>>> +#include <linux/delay.h>
>>>> +#include <linux/mfd/core.h>
>>>> +#include <linux/mfd/cros_ec.h>
>>>> +#include <linux/mfd/cros_ec_commands.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/pci.h>
>>>> +#include <linux/intel-ish-client-if.h>
>>>> +
>>
>> I think that this patch depends on another patchset that's in linux-next but
>> diddn't land yet to mainline. Do you know if the dependencies are queued for
>> next merge window? Can you provide the exact patches that this patch depends on?
> 
> Enric, 
> Sorry I missed mentioning this. 
>  
> The patch have dependency on intel-ish-hid stack on hid git tree,
> branch for-5.2/ish
> https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git/log/?h=for-5.2/ish
> 
> Srinivas, 
> Could you tell if the patches are queued for next merge window?
> 

If you can provide an immutable branch I can queue the patch to the
chrome-platform now, otherwise I'll wait to see this merged and then apply. I
did some minor style modifications but from my side the patch is fine to go for
chrome-platform-5.2

Thanks,
 Enric


> Thanks
> Rushikesh
> 
> 
>>
>> Thanks,
>>  Enric
>>
>>
>>>> +/*
>>>> + * ISH TX/RX ring buffer pool size
>>>> + *
>>>> + * The AP->ISH messages and corresponding ISH->AP responses are
>>>> + * serialized. We need 1 TX and 1 RX buffer for these.
>>>> + *
>>>> + * The MKBP ISH->AP events are serialized. We need one additional RX
>>>> + * buffer for them.
>>>> + */
>>>> +#define CROS_ISH_CL_TX_RING_SIZE               8
>>>> +#define CROS_ISH_CL_RX_RING_SIZE               8
>>>> +
>>>> +/* ISH CrOS EC Host Commands */
>>>> +enum cros_ec_ish_channel {
>>>> +       CROS_EC_COMMAND = 1,                    /* AP->ISH message */
>>>> +       CROS_MKBP_EVENT = 2,                    /* ISH->AP events */
>>>> +};
>>>> +
>>>> +/*
>>>> + * ISH firmware timeout for 1 message send failure is 1Hz, and the
>>>> + * firmware will retry 2 times, so 3Hz is used for timeout.
>>>> + */
>>>> +#define ISHTP_SEND_TIMEOUT                     (3 * HZ)
>>>> +
>>>> +/* ISH Transport CrOS EC ISH client unique GUID */
>>>> +static const guid_t cros_ish_guid =
>>>> +       GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
>>>> +                 0xb0, 0xd8, 0x9e, 0x7c, 0xda, 0xe0, 0xd6, 0xa0);
>>>> +
>>>> +struct header {
>>>> +       u8 channel;
>>>> +       u8 status;
>>>> +       u8 reserved[2];
>>>> +} __packed;
>>>> +
>>>> +struct cros_ish_out_msg {
>>>> +       struct header hdr;
>>>> +       struct ec_host_request ec_request;
>>>> +} __packed;
>>>> +
>>>> +struct cros_ish_in_msg {
>>>> +       struct header hdr;
>>>> +       struct ec_host_response ec_response;
>>>> +} __packed;
>>>> +
>>>> +#define IN_MSG_EC_RESPONSE_PREAMBLE                                    \
>>>> +       offsetof(struct cros_ish_in_msg, ec_response)
>>>> +
>>>> +#define OUT_MSG_EC_REQUEST_PREAMBLE                                    \
>>>> +       offsetof(struct cros_ish_out_msg, ec_request)
>>>> +
>>>> +#define cl_data_to_dev(client_data) ishtp_device((client_data)->cl_device)
>>>> +
>>>> +/*
>>>> + * The Read-Write Semaphore is used to prevent message TX or RX while
>>>> + * the ishtp client is being initialized or undergoing reset.
>>>> + *
>>>> + * The readers are the kernel function calls responsible for IA->ISH
>>>> + * and ISH->AP messaging.
>>>> + *
>>>> + * The writers are .reset() and .probe() function.
>>>> + */
>>>> +DECLARE_RWSEM(init_lock);
>>>> +
>>>> +/**
>>>> + * struct response_info - Encapsulate firmware response related
>>>> + *                     information for passing between function
>>>> + *                     ish_send() and process_recv() callback.
>>>> + * @data:              Copy the data received from firmware here.
>>>> + * @max_size:          Max size allocated for the @data buffer. If the
>>>> + *                     received data exceeds this value, we log an
>>>> + *                     error.
>>>> + * @size:              Actual size of data received from firmware.
>>>> + * @error:             0 for success, negative error code for a
>>>> + *                     failure in function process_recv().
>>>> + * @received:          Set to true on receiving a valid firmware
>>>> + *                     response to host command
>>>> + * @wait_queue:                Wait queue for Host firmware loading where the
>>>> + *                     client sends message to ISH firmware and waits
>>>> + *                     for response
>>>> + */
>>>> +struct response_info {
>>>> +       void *data;
>>>> +       size_t max_size;
>>>> +       size_t size;
>>>> +       int error;
>>>> +       bool received;
>>>> +       wait_queue_head_t wait_queue;
>>>> +};
>>>> +
>>>> +/**
>>>> + * struct ishtp_cl_data - Encapsulate per ISH TP Client.
>>>> + * @cros_ish_cl:       ISHTP firmware client instance.
>>>> + * @cl_device:         ISHTP client device instance.
>>>> + * @response:          Firmware response information for passing
>>>> + *                     between function ish_send() and process_recv()
>>>> + *                     callback.
>>>> + * @work_ishtp_reset:  Work queue reset handling.
>>>> + * @work_ec_evt:       Work queue for EC events.
>>>> + * @ec_dev:            CrOS EC MFD device.
>>>> + *
>>>> + * This structure is used to store per client data.
>>>> + */
>>>> +struct ishtp_cl_data {
>>>> +       struct ishtp_cl *cros_ish_cl;
>>>> +       struct ishtp_cl_device *cl_device;
>>>> +
>>>> +       /*
>>>> +        * Used for passing firmware response information between
>>>> +        * ish_send() and process_recv() callback.
>>>> +        */
>>>> +       struct response_info response;
>>>> +
>>>> +       struct work_struct work_ishtp_reset;
>>>> +       struct work_struct work_ec_evt;
>>>> +       struct cros_ec_device *ec_dev;
>>>> +};
>>>> +
>>>> +/**
>>>> + * ish_evt_handler - ISH to AP event handler
>>>> + * @work:              Work struct
>>>> + */
>>>> +static void ish_evt_handler(struct work_struct *work)
>>>> +{
>>>> +       struct ishtp_cl_data *client_data =
>>>> +               container_of(work, struct ishtp_cl_data, work_ec_evt);
>>>> +       struct cros_ec_device *ec_dev = client_data->ec_dev;
>>>> +
>>>> +       if (cros_ec_get_next_event(ec_dev, NULL) > 0) {
>>>> +               blocking_notifier_call_chain(&ec_dev->event_notifier,
>>>> +                                            0, ec_dev);
>>>> +       }
>>>> +}
>>>> +
>>>> +/**
>>>> + * ish_send() - Send message from host to firmware
>>>> + * @client_data:       Client data instance
>>>> + * @out_msg:           Message buffer to be sent to firmware
>>>> + * @out_size:          Size of out going message
>>>> + * @in_msg:            Message buffer where the incoming data copied.
>>>> + *                     This buffer is allocated by calling
>>>> + * @in_size:           Max size of incoming message
>>>> + *
>>>> + * Return: Number of bytes copied in the in_msg on success, negative
>>>> + * error code on failure.
>>>> + */
>>>> +static int ish_send(struct ishtp_cl_data *client_data,
>>>> +                   u8 *out_msg, size_t out_size,
>>>> +                   u8 *in_msg, size_t in_size)
>>>> +{
>>>> +       int rv;
>>>> +       struct header *out_hdr = (struct header *)out_msg;
>>>> +       struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl;
>>>> +
>>>> +       dev_dbg(cl_data_to_dev(client_data),
>>>> +               "%s: channel=%02u status=%02u\n",
>>>> +               __func__, out_hdr->channel, out_hdr->status);
>>>> +
>>>> +       /* Setup for incoming response */
>>>> +       client_data->response.data = in_msg;
>>>> +       client_data->response.max_size = in_size;
>>>> +       client_data->response.error = 0;
>>>> +       client_data->response.received = false;
>>>> +
>>>> +       rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
>>>> +       if (rv) {
>>>> +               dev_err(cl_data_to_dev(client_data),
>>>> +                       "ishtp_cl_send error %d\n", rv);
>>>> +               return rv;
>>>> +       }
>>>> +
>>>> +       wait_event_interruptible_timeout(client_data->response.wait_queue,
>>>> +                                        client_data->response.received,
>>>> +                                        ISHTP_SEND_TIMEOUT);
>>>> +       if (!client_data->response.received) {
>>>> +               dev_err(cl_data_to_dev(client_data),
>>>> +                       "Timed out for response to host message\n");
>>>> +               return -ETIMEDOUT;
>>>> +       }
>>>> +
>>>> +       if (client_data->response.error < 0)
>>>> +               return client_data->response.error;
>>>> +
>>>> +       return client_data->response.size;
>>>> +}
>>>> +
>>>> +/**
>>>> + * process_recv() -    Received and parse incoming packet
>>>> + * @cros_ish_cl:       Client instance to get stats
>>>> + * @rb_in_proc:                Host interface message buffer
>>>> + *
>>>> + * Parse the incoming packet. If it is a response packet then it will
>>>> + * update per instance flags and wake up the caller waiting to for the
>>>> + * response. If it is an event packet then it will schedule event work.
>>>> + */
>>>> +static void process_recv(struct ishtp_cl *cros_ish_cl,
>>>> +                        struct ishtp_cl_rb *rb_in_proc)
>>>> +{
>>>> +       size_t data_len = rb_in_proc->buf_idx;
>>>> +       struct ishtp_cl_data *client_data =
>>>> +               ishtp_get_client_data(cros_ish_cl);
>>>> +       struct device *dev = cl_data_to_dev(client_data);
>>>> +       struct cros_ish_in_msg *in_msg =
>>>> +               (struct cros_ish_in_msg *)rb_in_proc->buffer.data;
>>>> +
>>>> +       /* Proceed only if reset or init is not in progress */
>>>> +       if (!down_read_trylock(&init_lock)) {
>>>> +               /* Free the buffer */
>>>> +               ishtp_cl_io_rb_recycle(rb_in_proc);
>>>> +               dev_warn(dev,
>>>> +                        "Host is not ready to receive incoming messages\n");
>>>> +               return;
>>>> +       }
>>>> +
>>>> +       /*
>>>> +        * All firmware messages contain a header. Check the buffer size
>>>> +        * before accessing elements inside.
>>>> +        */
>>>> +       if (!rb_in_proc->buffer.data) {
>>>> +               dev_warn(dev, "rb_in_proc->buffer.data returned null");
>>>> +               client_data->response.error = -EBADMSG;
>>>> +               goto end_error;
>>>> +       }
>>>> +
>>>> +       if (data_len < sizeof(struct header)) {
>>>> +               dev_err(dev, "data size %zu is less than header %zu\n",
>>>> +                       data_len, sizeof(struct header));
>>>> +               client_data->response.error = -EMSGSIZE;
>>>> +               goto end_error;
>>>> +       }
>>>> +
>>>> +       dev_dbg(dev, "channel=%02u status=%02u\n",
>>>> +               in_msg->hdr.channel, in_msg->hdr.status);
>>>> +
>>>> +       switch (in_msg->hdr.channel) {
>>>> +       case CROS_EC_COMMAND:
>>>> +               /* Sanity check */
>>>> +               if (!client_data->response.data) {
>>>> +                       dev_err(dev,
>>>> +                               "Receiving buffer is null. Should be allocated by calling function\n");
>>>> +                       client_data->response.error = -EINVAL;
>>>> +                       goto error_wake_up;
>>>> +               }
>>>> +
>>>> +               if (client_data->response.received) {
>>>> +                       dev_err(dev,
>>>> +                               "Previous firmware message not yet processed\n");
>>>> +                       client_data->response.error = -EINVAL;
>>>> +                       goto error_wake_up;
>>>> +               }
>>>> +
>>>> +               if (data_len > client_data->response.max_size) {
>>>> +                       dev_err(dev,
>>>> +                               "Received buffer size %zu is larger than allocated buffer %zu\n",
>>>> +                               data_len, client_data->response.max_size);
>>>> +                       client_data->response.error = -EMSGSIZE;
>>>> +                       goto error_wake_up;
>>>> +               }
>>>> +
>>>> +               if (in_msg->hdr.status) {
>>>> +                       dev_err(dev, "firmware returned status %d\n",
>>>> +                               in_msg->hdr.status);
>>>> +                       client_data->response.error = -EIO;
>>>> +                       goto error_wake_up;
>>>> +               }
>>>> +
>>>> +               /* Update the actual received buffer size */
>>>> +               client_data->response.size = data_len;
>>>> +
>>>> +               /*
>>>> +                * Copy the buffer received in firmware response for the
>>>> +                * calling thread.
>>>> +                */
>>>> +               memcpy(client_data->response.data,
>>>> +                      rb_in_proc->buffer.data, data_len);
>>>> +
>>>> +               /* Set flag before waking up the caller */
>>>> +               client_data->response.received = true;
>>>> +error_wake_up:
>>>> +               /* Wake the calling thread */
>>>> +               wake_up_interruptible(&client_data->response.wait_queue);
>>>> +
>>>> +               break;
>>>> +
>>>> +       case CROS_MKBP_EVENT:
>>>> +               /* The event system doesn't send any data in buffer */
>>>> +               schedule_work(&client_data->work_ec_evt);
>>>> +
>>>> +               break;
>>>> +
>>>> +       default:
>>>> +               dev_err(dev, "Invalid channel=%02d\n", in_msg->hdr.channel);
>>>> +       }
>>>> +
>>>> +end_error:
>>>> +       /* Free the buffer */
>>>> +       ishtp_cl_io_rb_recycle(rb_in_proc);
>>>> +
>>>> +       up_read(&init_lock);
>>>> +}
>>>> +
>>>> +/**
>>>> + * ish_event_cb() - bus driver callback for incoming message
>>>> + * @cl_device:         ISHTP client device for which this message is
>>>> + *                     targeted.
>>>> + *
>>>> + * Remove the packet from the list and process the message by calling
>>>> + * process_recv.
>>>> + */
>>>> +static void ish_event_cb(struct ishtp_cl_device *cl_device)
>>>> +{
>>>> +       struct ishtp_cl_rb *rb_in_proc;
>>>> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
>>>> +
>>>> +       while ((rb_in_proc = ishtp_cl_rx_get_rb(cros_ish_cl)) != NULL) {
>>>> +               /* Decide what to do with received data */
>>>> +               process_recv(cros_ish_cl, rb_in_proc);
>>>> +       }
>>>> +}
>>>> +
>>>> +/**
>>>> + * cros_ish_init() - Init function for ISHTP client
>>>> + * @cros_ish_cl:       ISHTP client instance
>>>> + *
>>>> + * This function complete the initializtion of the client.
>>>> + *
>>>> + * Return: 0 for success, negative error code for failure.
>>>> + */
>>>> +static int cros_ish_init(struct ishtp_cl *cros_ish_cl)
>>>> +{
>>>> +       int rv;
>>>> +       struct ishtp_device *dev;
>>>> +       struct ishtp_fw_client *fw_client;
>>>> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
>>>> +
>>>> +       rv = ishtp_cl_link(cros_ish_cl);
>>>> +       if (rv) {
>>>> +               dev_err(cl_data_to_dev(client_data),
>>>> +                       "ishtp_cl_link failed\n");
>>>> +               return rv;
>>>> +       }
>>>> +
>>>> +       dev = ishtp_get_ishtp_device(cros_ish_cl);
>>>> +
>>>> +       /* Connect to firmware client */
>>>> +       ishtp_set_tx_ring_size(cros_ish_cl, CROS_ISH_CL_TX_RING_SIZE);
>>>> +       ishtp_set_rx_ring_size(cros_ish_cl, CROS_ISH_CL_RX_RING_SIZE);
>>>> +
>>>> +       fw_client = ishtp_fw_cl_get_client(dev, &cros_ish_guid);
>>>> +       if (!fw_client) {
>>>> +               dev_err(cl_data_to_dev(client_data),
>>>> +                       "ish client uuid not found\n");
>>>> +               rv = -ENOENT;
>>>> +               goto err_cl_unlink;
>>>> +       }
>>>> +
>>>> +       ishtp_cl_set_fw_client_id(cros_ish_cl,
>>>> +                                 ishtp_get_fw_client_id(fw_client));
>>>> +       ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_CONNECTING);
>>>> +
>>>> +       rv = ishtp_cl_connect(cros_ish_cl);
>>>> +       if (rv) {
>>>> +               dev_err(cl_data_to_dev(client_data),
>>>> +                       "client connect fail\n");
>>>> +               goto err_cl_unlink;
>>>> +       }
>>>> +
>>>> +       ishtp_register_event_cb(client_data->cl_device, ish_event_cb);
>>>> +       return 0;
>>>> +
>>>> +err_cl_unlink:
>>>> +       ishtp_cl_unlink(cros_ish_cl);
>>>> +       return rv;
>>>> +}
>>>> +
>>>> +/**
>>>> + * cros_ish_deinit() - Deinit function for ISHTP client
>>>> + * @cros_ish_cl:       ISHTP client instance
>>>> + *
>>>> + * Unlink and free cros_ec client
>>>> + */
>>>> +static void cros_ish_deinit(struct ishtp_cl *cros_ish_cl)
>>>> +{
>>>> +       ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
>>>> +       ishtp_cl_disconnect(cros_ish_cl);
>>>> +       ishtp_cl_unlink(cros_ish_cl);
>>>> +       ishtp_cl_flush_queues(cros_ish_cl);
>>>> +
>>>> +       /* Disband and free all Tx and Rx client-level rings */
>>>> +       ishtp_cl_free(cros_ish_cl);
>>>> +}
>>>> +
>>>> +/**
>>>> + * prepare_cros_ec_rx() - Check & prepare receive buffer
>>>> + * @in_msg:            Incoming message buffer
>>>> + * @cros_ec_command    cros_ec command used to send & receive data
>>>> + *
>>>> + * Check the received buffer. Convert to cros_ec_command format.
>>>> + */
>>>> +static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
>>>> +                             const struct cros_ish_in_msg *in_msg,
>>>> +                             struct cros_ec_command *msg)
>>>> +{
>>>> +       u8 sum = 0;
>>>> +       int i, rv, offset;
>>>> +
>>>> +       /* Check response error code */
>>>> +       msg->result = in_msg->ec_response.result;
>>>> +       rv = cros_ec_check_result(ec_dev, msg);
>>>> +       if (rv < 0)
>>>> +               return rv;
>>>> +
>>>> +       if (in_msg->ec_response.data_len > msg->insize) {
>>>> +               dev_err(ec_dev->dev, "Packet too long (%d bytes, expected %d)",
>>>> +                       in_msg->ec_response.data_len, msg->insize);
>>>> +               return -ENOSPC;
>>>> +       }
>>>> +
>>>> +       /* Copy response packet payload and compute checksum */
>>>> +       for (i = 0; i < sizeof(struct ec_host_response); i++)
>>>> +               sum += ((u8 *)in_msg)[IN_MSG_EC_RESPONSE_PREAMBLE + i];
>>>> +
>>>> +       offset = sizeof(struct cros_ish_in_msg);
>>>> +       for (i = 0; i < in_msg->ec_response.data_len; i++)
>>>> +               sum += msg->data[i] = ((u8 *)in_msg)[offset + i];
>>>> +
>>>> +       if (sum) {
>>>> +               dev_dbg(ec_dev->dev, "Bad received packet checksum %d\n", sum);
>>>> +               return -EBADMSG;
>>>> +       }
>>>> +
>>>> +       return 0;
>>>> +}
>>>> +
>>>> +static int cros_ec_pkt_xfer_ish(struct cros_ec_device *ec_dev,
>>>> +                               struct cros_ec_command *msg)
>>>> +{
>>>> +       int rv;
>>>> +       struct ishtp_cl *cros_ish_cl = ec_dev->priv;
>>>> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
>>>> +       struct device *dev = cl_data_to_dev(client_data);
>>>> +       struct cros_ish_in_msg *in_msg = (struct cros_ish_in_msg *)ec_dev->din;
>>>> +       struct cros_ish_out_msg *out_msg =
>>>> +               (struct cros_ish_out_msg *)ec_dev->dout;
>>>> +       size_t in_size = sizeof(struct cros_ish_in_msg) + msg->insize;
>>>> +       size_t out_size = sizeof(struct cros_ish_out_msg) + msg->outsize;
>>>> +
>>>> +       /* Proceed only if reset-init is not in progress */
>>>> +       if (!down_read_trylock(&init_lock)) {
>>>> +               dev_warn(dev,
>>>> +                        "Host is not ready to send messages to ISH. Try again\n");
>>>> +               return -EAGAIN;
>>>> +       }
>>>> +
>>>> +       /* Sanity checks */
>>>> +       if (in_size > ec_dev->din_size) {
>>>> +               dev_err(dev,
>>>> +                       "Incoming payload size %zu is too large for ec_dev->din_size %d\n",
>>>> +                       in_size, ec_dev->din_size);
>>>> +               return -EMSGSIZE;
>>>> +       }
>>>> +
>>>> +       if (out_size > ec_dev->dout_size) {
>>>> +               dev_err(dev,
>>>> +                       "Outgoing payload size %zu is too large for ec_dev->dout_size %d\n",
>>>> +                       out_size, ec_dev->dout_size);
>>>> +               return -EMSGSIZE;
>>>> +       }
>>>> +
>>>> +       /* Prepare the package to be sent over ISH TP */
>>>> +       out_msg->hdr.channel = CROS_EC_COMMAND;
>>>> +       out_msg->hdr.status = 0;
>>>> +
>>>> +       ec_dev->dout += OUT_MSG_EC_REQUEST_PREAMBLE;
>>>> +       cros_ec_prepare_tx(ec_dev, msg);
>>>> +       ec_dev->dout -= OUT_MSG_EC_REQUEST_PREAMBLE;
>>>> +
>>>> +       dev_dbg(dev,
>>>> +               "out_msg: struct_ver=0x%x checksum=0x%x command=0x%x command_ver=0x%x data_len=0x%x\n",
>>>> +               out_msg->ec_request.struct_version,
>>>> +               out_msg->ec_request.checksum,
>>>> +               out_msg->ec_request.command,
>>>> +               out_msg->ec_request.command_version,
>>>> +               out_msg->ec_request.data_len);
>>>> +
>>>> +       /* Send command to ISH EC firmware and read response */
>>>> +       rv = ish_send(client_data,
>>>> +                     (u8 *)out_msg, out_size,
>>>> +                     (u8 *)in_msg, in_size);
>>>> +       if (rv < 0)
>>>> +               goto end_error;
>>>> +
>>>> +       rv = prepare_cros_ec_rx(ec_dev, in_msg, msg);
>>>> +       if (rv)
>>>> +               goto end_error;
>>>> +
>>>> +       rv = in_msg->ec_response.data_len;
>>>> +
>>>> +       dev_dbg(dev,
>>>> +               "in_msg: struct_ver=0x%x checksum=0x%x result=0x%x data_len=0x%x\n",
>>>> +               in_msg->ec_response.struct_version,
>>>> +               in_msg->ec_response.checksum,
>>>> +               in_msg->ec_response.result,
>>>> +               in_msg->ec_response.data_len);
>>>> +
>>>> +end_error:
>>>> +       if (msg->command == EC_CMD_REBOOT_EC)
>>>> +               msleep(EC_REBOOT_DELAY_MS);
>>>> +
>>>> +       up_read(&init_lock);
>>>> +
>>>> +       return rv;
>>>> +}
>>>> +
>>>> +static int cros_ec_dev_init(struct ishtp_cl_data *client_data)
>>>> +{
>>>> +       struct cros_ec_device *ec_dev;
>>>> +       struct device *dev = cl_data_to_dev(client_data);
>>>> +
>>>> +       ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
>>>> +       if (!ec_dev)
>>>> +               return -ENOMEM;
>>>> +
>>>> +       client_data->ec_dev = ec_dev;
>>>> +       dev->driver_data = ec_dev;
>>>> +
>>>> +       ec_dev->dev = dev;
>>>> +       ec_dev->priv = client_data->cros_ish_cl;
>>>> +       ec_dev->cmd_xfer = NULL;
>>>> +       ec_dev->pkt_xfer = cros_ec_pkt_xfer_ish;
>>>> +       ec_dev->phys_name = dev_name(dev);
>>>> +       ec_dev->din_size = sizeof(struct cros_ish_in_msg) +
>>>> +                          sizeof(struct ec_response_get_protocol_info);
>>>> +       ec_dev->dout_size = sizeof(struct cros_ish_out_msg);
>>>> +
>>>> +       return cros_ec_register(ec_dev);
>>>> +}
>>>> +
>>>> +static void reset_handler(struct work_struct *work)
>>>> +{
>>>> +       int rv;
>>>> +       struct device *dev;
>>>> +       struct ishtp_cl *cros_ish_cl;
>>>> +       struct ishtp_cl_device *cl_device;
>>>> +       struct ishtp_cl_data *client_data =
>>>> +               container_of(work, struct ishtp_cl_data, work_ishtp_reset);
>>>> +
>>>> +       /* Lock for reset to complete */
>>>> +       down_write(&init_lock);
>>>> +
>>>> +       cros_ish_cl = client_data->cros_ish_cl;
>>>> +       cl_device = client_data->cl_device;
>>>> +
>>>> +       /* Unlink, flush queues & start again */
>>>> +       ishtp_cl_unlink(cros_ish_cl);
>>>> +       ishtp_cl_flush_queues(cros_ish_cl);
>>>> +       ishtp_cl_free(cros_ish_cl);
>>>> +
>>>> +       cros_ish_cl = ishtp_cl_allocate(cl_device);
>>>> +       if (!cros_ish_cl) {
>>>> +               up_write(&init_lock);
>>>> +               return;
>>>> +       }
>>>> +
>>>> +       ishtp_set_drvdata(cl_device, cros_ish_cl);
>>>> +       ishtp_set_client_data(cros_ish_cl, client_data);
>>>> +       client_data->cros_ish_cl = cros_ish_cl;
>>>> +
>>>> +       rv = cros_ish_init(cros_ish_cl);
>>>> +       if (rv) {
>>>> +               ishtp_cl_free(cros_ish_cl);
>>>> +               dev_err(cl_data_to_dev(client_data), "Reset Failed\n");
>>>> +               up_write(&init_lock);
>>>> +               return;
>>>> +       }
>>>> +
>>>> +       /* Refresh ec_dev device pointers */
>>>> +       client_data->ec_dev->priv = client_data->cros_ish_cl;
>>>> +       dev = cl_data_to_dev(client_data);
>>>> +       dev->driver_data = client_data->ec_dev;
>>>> +
>>>> +       dev_info(cl_data_to_dev(client_data), "Chrome EC ISH reset done\n");
>>>> +
>>>> +       up_write(&init_lock);
>>>> +}
>>>> +
>>>> +/**
>>>> + * cros_ec_ishtp_probe() - ISHTP client driver probe callback
>>>> + * @cl_device:         ISHTP client device instance
>>>> + *
>>>> + * Return: 0 for success, negative error code for failure.
>>>> + */
>>>> +static int cros_ec_ishtp_probe(struct ishtp_cl_device *cl_device)
>>>> +{
>>>> +       int rv;
>>>> +       struct ishtp_cl *cros_ish_cl;
>>>> +       struct ishtp_cl_data *client_data =
>>>> +               devm_kzalloc(ishtp_device(cl_device),
>>>> +                            sizeof(*client_data), GFP_KERNEL);
>>>> +       if (!client_data)
>>>> +               return -ENOMEM;
>>>> +
>>>> +       /* Lock for initialization to complete */
>>>> +       down_write(&init_lock);
>>>> +
>>>> +       cros_ish_cl = ishtp_cl_allocate(cl_device);
>>>> +       if (!cros_ish_cl) {
>>>> +               rv = -ENOMEM;
>>>> +               goto end_ishtp_cl_alloc_error;
>>>> +       }
>>>> +
>>>> +       ishtp_set_drvdata(cl_device, cros_ish_cl);
>>>> +       ishtp_set_client_data(cros_ish_cl, client_data);
>>>> +       client_data->cros_ish_cl = cros_ish_cl;
>>>> +       client_data->cl_device = cl_device;
>>>> +
>>>> +       init_waitqueue_head(&client_data->response.wait_queue);
>>>> +
>>>> +       INIT_WORK(&client_data->work_ishtp_reset,
>>>> +                 reset_handler);
>>>> +       INIT_WORK(&client_data->work_ec_evt,
>>>> +                 ish_evt_handler);
>>>> +
>>>> +       rv = cros_ish_init(cros_ish_cl);
>>>> +       if (rv)
>>>> +               goto end_ishtp_cl_init_error;
>>>> +
>>>> +       ishtp_get_device(cl_device);
>>>> +
>>>> +       up_write(&init_lock);
>>>> +
>>>> +       /* Register croc_ec_dev mfd */
>>>> +       rv = cros_ec_dev_init(client_data);
>>>> +       if (rv)
>>>> +               goto end_cros_ec_dev_init_error;
>>>> +
>>>> +       return 0;
>>>> +
>>>> +end_cros_ec_dev_init_error:
>>>> +       ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
>>>> +       ishtp_cl_disconnect(cros_ish_cl);
>>>> +       ishtp_cl_unlink(cros_ish_cl);
>>>> +       ishtp_cl_flush_queues(cros_ish_cl);
>>>> +       ishtp_put_device(cl_device);
>>>> +end_ishtp_cl_init_error:
>>>> +       ishtp_cl_free(cros_ish_cl);
>>>> +end_ishtp_cl_alloc_error:
>>>> +       up_write(&init_lock);
>>>> +       return rv;
>>>> +}
>>>> +
>>>> +/**
>>>> + * cros_ec_ishtp_remove() - ISHTP client driver remove callback
>>>> + * @cl_device:         ISHTP client device instance
>>>> + *
>>>> + * Return: 0
>>>> + */
>>>> +static int cros_ec_ishtp_remove(struct ishtp_cl_device *cl_device)
>>>> +{
>>>> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
>>>> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
>>>> +
>>>> +       cancel_work_sync(&client_data->work_ishtp_reset);
>>>> +       cancel_work_sync(&client_data->work_ec_evt);
>>>> +       cros_ish_deinit(cros_ish_cl);
>>>> +       ishtp_put_device(cl_device);
>>>> +
>>>> +       return 0;
>>>> +}
>>>> +
>>>> +/**
>>>> + * cros_ec_ishtp_reset() - ISHTP client driver reset callback
>>>> + * @cl_device:         ISHTP client device instance
>>>> + *
>>>> + * Return: 0
>>>> + */
>>>> +static int cros_ec_ishtp_reset(struct ishtp_cl_device *cl_device)
>>>> +{
>>>> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
>>>> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
>>>> +
>>>> +       schedule_work(&client_data->work_ishtp_reset);
>>>> +
>>>> +       return 0;
>>>> +}
>>>> +
>>>> +/**
>>>> + * cros_ec_ishtp_suspend() - ISHTP client driver suspend callback
>>>> + * @device:    device instance
>>>> + *
>>>> + * Return: 0 for success, negative error code for failure.
>>>> + */
>>>> +static int __maybe_unused cros_ec_ishtp_suspend(struct device *device)
>>>> +{
>>>> +       struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
>>>> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
>>>> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
>>>> +
>>>> +       return cros_ec_suspend(client_data->ec_dev);
>>>> +}
>>>> +
>>>> +/**
>>>> + * cros_ec_ishtp_resume() - ISHTP client driver resume callback
>>>> + * @device:    device instance
>>>> + *
>>>> + * Return: 0 for success, negative error code for failure.
>>>> + */
>>>> +static int __maybe_unused cros_ec_ishtp_resume(struct device *device)
>>>> +{
>>>> +       struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
>>>> +       struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
>>>> +       struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
>>>> +
>>>> +       return cros_ec_resume(client_data->ec_dev);
>>>> +}
>>>> +
>>>> +static SIMPLE_DEV_PM_OPS(cros_ec_ishtp_pm_ops, cros_ec_ishtp_suspend,
>>>> +                        cros_ec_ishtp_resume);
>>>> +
>>>> +static struct ishtp_cl_driver  cros_ec_ishtp_driver = {
>>>> +       .name = "cros_ec_ishtp",
>>>> +       .guid = &cros_ish_guid,
>>>> +       .probe = cros_ec_ishtp_probe,
>>>> +       .remove = cros_ec_ishtp_remove,
>>>> +       .reset = cros_ec_ishtp_reset,
>>>> +       .driver = {
>>>> +               .pm = &cros_ec_ishtp_pm_ops,
>>>> +       },
>>>> +};
>>>> +
>>>> +static int __init cros_ec_ishtp_mod_init(void)
>>>> +{
>>>> +       return ishtp_cl_driver_register(&cros_ec_ishtp_driver, THIS_MODULE);
>>>> +}
>>>> +
>>>> +static void __exit cros_ec_ishtp_mod_exit(void)
>>>> +{
>>>> +       ishtp_cl_driver_unregister(&cros_ec_ishtp_driver);
>>>> +}
>>>> +
>>>> +module_init(cros_ec_ishtp_mod_init);
>>>> +module_exit(cros_ec_ishtp_mod_exit);
>>>> +
>>>> +MODULE_DESCRIPTION("ChromeOS EC ISHTP Client Driver");
>>>> +MODULE_AUTHOR("Rushikesh S Kadam <rushikesh.s.kadam@intel.com>");
>>>> +
>>>> +MODULE_LICENSE("GPL v2");
>>>> +MODULE_ALIAS("ishtp:*");
>>>> --
>>>> 1.9.1
>>>>
> 

Re: [PATCH v3] platform: chrome: Add ChromeOS EC ISHTP driver

[Srinivas Pandruvada]

On Thu, 2019-04-11 at 15:54 +0200, Enric Balletbo i Serra wrote:
> Hi,
> 
> On 11/4/19 13:10, Rushikesh S Kadam wrote:
> > Hi Enric, Srinivas
> > 
> > On Thu, Apr 11, 2019 at 12:55:13PM +0200, Enric Balletbo i Serra
> > wrote:
> > > Hi,
> > > 
> > > On 10/4/19 17:31, Jett Rink wrote:
> > > > Reviewed-by: Jett Rink <jettrink@chromium.org>
> > > > Tested-by: Jett Rink <jettrink@chromium.org>
> > > > 
> > > > 
> > > > On Sun, Apr 7, 2019 at 6:10 AM Rushikesh S Kadam
> > > > <rushikesh.s.kadam@intel.com> wrote:
> > > > > 
> > > > > This driver implements a slim layer to enable the ChromeOS
> > > > > EC kernel stack (cros_ec) to communicate with ChromeOS EC
> > > > > firmware running on the Intel Integrated Sensor Hub (ISH).
> > > > > 
> > > > > The driver registers a ChromeOS EC MFD device to connect
> > > > > with cros_ec kernel stack (upper layer), and it registers a
> > > > > client with the ISH Transport Protocol bus (lower layer) to
> > > > > talk with the ISH firwmare. See description of the ISHTP
> > > > > protocol at Documentation/hid/intel-ish-hid.txt
> > > > > 
> > > > > Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com
> > > > > >
> > > > > ---
> > > > > 
> > > > > v3
> > > > >  - Made several changes to improve code readability. Replaced
> > > > >    multiple cl_data_to_dev(client_data) with dev variable.
> > > > > Use
> > > > >    reverse Xmas tree for variable defintion where it made
> > > > > sense.
> > > > >    Dropped few debug prints. Add docstring for function
> > > > >    prepare_cros_ec_rx().
> > > > >  - Fix code in function prepare_cros_ec_rx() under label
> > > > >    end_cros_ec_dev_init_error.
> > > > >  - Recycle buffer in process_recv() on failing to obtain the
> > > > >    semaphore.
> > > > >  - Increase ISHTP TX/RX ring buffer size to 8.
> > > > >  - Alphabetically ordered CROS_EC_ISHTP entries in Makefile
> > > > > and
> > > > >    Kconfig.
> > > > >  - Updated commit message.
> > > > > 
> > > > > v2
> > > > >  - Dropped unused "reset" parameter in function
> > > > > cros_ec_init()
> > > > >  - Change driver name to cros_ec_ishtp to be consistent with
> > > > > other
> > > > >    references in the code.
> > > > >  - Fixed a few typos.
> > > > > 
> > > > > v1
> > > > >  - Initial version
> > > > > 
> > > > >  drivers/platform/chrome/Kconfig         |  13 +
> > > > >  drivers/platform/chrome/Makefile        |   1 +
> > > > >  drivers/platform/chrome/cros_ec_ishtp.c | 765
> > > > > ++++++++++++++++++++++++++++++++
> > > > >  3 files changed, 779 insertions(+)
> > > > >  create mode 100644 drivers/platform/chrome/cros_ec_ishtp.c
> > > > > 
> > > > > diff --git a/drivers/platform/chrome/Kconfig
> > > > > b/drivers/platform/chrome/Kconfig
> > > > > index 16b1615..5848179 100644
> > > > > --- a/drivers/platform/chrome/Kconfig
> > > > > +++ b/drivers/platform/chrome/Kconfig
> > > > > @@ -62,6 +62,19 @@ config CROS_EC_I2C
> > > > >           a checksum. Failing accesses will be retried three
> > > > > times to
> > > > >           improve reliability.
> > > > > 
> > > > > +config CROS_EC_ISHTP
> > > > > +       tristate "ChromeOS Embedded Controller (ISHTP)"
> > > > > +       depends on MFD_CROS_EC
> > > > > +       depends on INTEL_ISH_HID
> > > > > +       help
> > > > > +         If you say Y here, you get support for talking to
> > > > > the ChromeOS EC
> > > > > +         firmware running on Intel Integrated Sensor Hub
> > > > > (ISH), using the
> > > > > +         ISH Transport protocol (ISH-TP). This uses a simple
> > > > > byte-level
> > > > > +         protocol with a checksum.
> > > > > +
> > > > > +         To compile this driver as a module, choose M here:
> > > > > the
> > > > > +         module will be called cros_ec_ishtp.
> > > > > +
> > > > >  config CROS_EC_SPI
> > > > >         tristate "ChromeOS Embedded Controller (SPI)"
> > > > >         depends on MFD_CROS_EC && SPI
> > > > > diff --git a/drivers/platform/chrome/Makefile
> > > > > b/drivers/platform/chrome/Makefile
> > > > > index cd591bf..4efe102 100644
> > > > > --- a/drivers/platform/chrome/Makefile
> > > > > +++ b/drivers/platform/chrome/Makefile
> > > > > @@ -7,6 +7,7 @@ cros_ec_ctl-objs                        :=
> > > > > cros_ec_sysfs.o cros_ec_lightbar.o \
> > > > >                                            cros_ec_vbc.o
> > > > > cros_ec_debugfs.o
> > > > >  obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
> > > > >  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
> > > > > +obj-$(CONFIG_CROS_EC_ISHTP)            += cros_ec_ishtp.o
> > > > >  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
> > > > >  cros_ec_lpcs-objs                      := cros_ec_lpc.o
> > > > > cros_ec_lpc_reg.o
> > > > >  cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC) += cros_ec_lpc_mec.o
> > > > > diff --git a/drivers/platform/chrome/cros_ec_ishtp.c
> > > > > b/drivers/platform/chrome/cros_ec_ishtp.c
> > > > > new file mode 100644
> > > > > index 0000000..b1d19c4
> > > > > --- /dev/null
> > > > > +++ b/drivers/platform/chrome/cros_ec_ishtp.c
> > > > > @@ -0,0 +1,765 @@
> > > > > +// SPDX-License-Identifier: GPL-2.0
> > > > > +/*
> > > > > + * ISHTP client driver for talking to the Chrome OS EC
> > > > > firmware running
> > > > > + * on Intel Integrated Sensor Hub (ISH) using the ISH
> > > > > Transport protocol
> > > > > + * (ISH-TP).
> > > > > + *
> > > > > + * Copyright (c) 2019, Intel Corporation.
> > > > > + */
> > > > > +
> > > > > +#include <linux/delay.h>
> > > > > +#include <linux/mfd/core.h>
> > > > > +#include <linux/mfd/cros_ec.h>
> > > > > +#include <linux/mfd/cros_ec_commands.h>
> > > > > +#include <linux/module.h>
> > > > > +#include <linux/pci.h>
> > > > > +#include <linux/intel-ish-client-if.h>
> > > > > +
> > > 
> > > I think that this patch depends on another patchset that's in
> > > linux-next but
> > > diddn't land yet to mainline. Do you know if the dependencies are
> > > queued for
> > > next merge window? Can you provide the exact patches that this
> > > patch depends on?
> > 
> > Enric, 
> > Sorry I missed mentioning this. 
> >  
> > The patch have dependency on intel-ish-hid stack on hid git tree,
> > branch for-5.2/ish
> > 
https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git/log/?h=for-5.2/ish
> > 
> > Srinivas, 
> > Could you tell if the patches are queued for next merge window?
> > 
Yes they are queued up for the next merge window. They are already in
linux-next. One option is to check if Jiri pick this patch as part of
his pull request. I am assuming that this patch doesn't depend on any
other ChromeOS EC patches.

Thanks,
Srinivas

> 
> If you can provide an immutable branch I can queue the patch to the
> chrome-platform now, otherwise I'll wait to see this merged and then
> apply. I
> did some minor style modifications but from my side the patch is fine
> to go for
> chrome-platform-5.2
> 
> Thanks,
>  Enric
> 
> 
> > Thanks
> > Rushikesh
> > 
> > 
> > > 
> > > Thanks,
> > >  Enric
> > > 
> > > 
> > > > > +/*
> > > > > + * ISH TX/RX ring buffer pool size
> > > > > + *
> > > > > + * The AP->ISH messages and corresponding ISH->AP responses
> > > > > are
> > > > > + * serialized. We need 1 TX and 1 RX buffer for these.
> > > > > + *
> > > > > + * The MKBP ISH->AP events are serialized. We need one
> > > > > additional RX
> > > > > + * buffer for them.
> > > > > + */
> > > > > +#define CROS_ISH_CL_TX_RING_SIZE               8
> > > > > +#define CROS_ISH_CL_RX_RING_SIZE               8
> > > > > +
> > > > > +/* ISH CrOS EC Host Commands */
> > > > > +enum cros_ec_ish_channel {
> > > > > +       CROS_EC_COMMAND = 1,                    /* AP->ISH
> > > > > message */
> > > > > +       CROS_MKBP_EVENT = 2,                    /* ISH->AP
> > > > > events */
> > > > > +};
> > > > > +
> > > > > +/*
> > > > > + * ISH firmware timeout for 1 message send failure is 1Hz,
> > > > > and the
> > > > > + * firmware will retry 2 times, so 3Hz is used for timeout.
> > > > > + */
> > > > > +#define ISHTP_SEND_TIMEOUT                     (3 * HZ)
> > > > > +
> > > > > +/* ISH Transport CrOS EC ISH client unique GUID */
> > > > > +static const guid_t cros_ish_guid =
> > > > > +       GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
> > > > > +                 0xb0, 0xd8, 0x9e, 0x7c, 0xda, 0xe0, 0xd6,
> > > > > 0xa0);
> > > > > +
> > > > > +struct header {
> > > > > +       u8 channel;
> > > > > +       u8 status;
> > > > > +       u8 reserved[2];
> > > > > +} __packed;
> > > > > +
> > > > > +struct cros_ish_out_msg {
> > > > > +       struct header hdr;
> > > > > +       struct ec_host_request ec_request;
> > > > > +} __packed;
> > > > > +
> > > > > +struct cros_ish_in_msg {
> > > > > +       struct header hdr;
> > > > > +       struct ec_host_response ec_response;
> > > > > +} __packed;
> > > > > +
> > > > > +#define
> > > > > IN_MSG_EC_RESPONSE_PREAMBLE                                  
> > > > >   \
> > > > > +       offsetof(struct cros_ish_in_msg, ec_response)
> > > > > +
> > > > > +#define
> > > > > OUT_MSG_EC_REQUEST_PREAMBLE                                  
> > > > >   \
> > > > > +       offsetof(struct cros_ish_out_msg, ec_request)
> > > > > +
> > > > > +#define cl_data_to_dev(client_data)
> > > > > ishtp_device((client_data)->cl_device)
> > > > > +
> > > > > +/*
> > > > > + * The Read-Write Semaphore is used to prevent message TX or
> > > > > RX while
> > > > > + * the ishtp client is being initialized or undergoing
> > > > > reset.
> > > > > + *
> > > > > + * The readers are the kernel function calls responsible for
> > > > > IA->ISH
> > > > > + * and ISH->AP messaging.
> > > > > + *
> > > > > + * The writers are .reset() and .probe() function.
> > > > > + */
> > > > > +DECLARE_RWSEM(init_lock);
> > > > > +
> > > > > +/**
> > > > > + * struct response_info - Encapsulate firmware response
> > > > > related
> > > > > + *                     information for passing between
> > > > > function
> > > > > + *                     ish_send() and process_recv()
> > > > > callback.
> > > > > + * @data:              Copy the data received from firmware
> > > > > here.
> > > > > + * @max_size:          Max size allocated for the @data
> > > > > buffer. If the
> > > > > + *                     received data exceeds this value, we
> > > > > log an
> > > > > + *                     error.
> > > > > + * @size:              Actual size of data received from
> > > > > firmware.
> > > > > + * @error:             0 for success, negative error code
> > > > > for a
> > > > > + *                     failure in function process_recv().
> > > > > + * @received:          Set to true on receiving a valid
> > > > > firmware
> > > > > + *                     response to host command
> > > > > + * @wait_queue:                Wait queue for Host firmware
> > > > > loading where the
> > > > > + *                     client sends message to ISH firmware
> > > > > and waits
> > > > > + *                     for response
> > > > > + */
> > > > > +struct response_info {
> > > > > +       void *data;
> > > > > +       size_t max_size;
> > > > > +       size_t size;
> > > > > +       int error;
> > > > > +       bool received;
> > > > > +       wait_queue_head_t wait_queue;
> > > > > +};
> > > > > +
> > > > > +/**
> > > > > + * struct ishtp_cl_data - Encapsulate per ISH TP Client.
> > > > > + * @cros_ish_cl:       ISHTP firmware client instance.
> > > > > + * @cl_device:         ISHTP client device instance.
> > > > > + * @response:          Firmware response information for
> > > > > passing
> > > > > + *                     between function ish_send() and
> > > > > process_recv()
> > > > > + *                     callback.
> > > > > + * @work_ishtp_reset:  Work queue reset handling.
> > > > > + * @work_ec_evt:       Work queue for EC events.
> > > > > + * @ec_dev:            CrOS EC MFD device.
> > > > > + *
> > > > > + * This structure is used to store per client data.
> > > > > + */
> > > > > +struct ishtp_cl_data {
> > > > > +       struct ishtp_cl *cros_ish_cl;
> > > > > +       struct ishtp_cl_device *cl_device;
> > > > > +
> > > > > +       /*
> > > > > +        * Used for passing firmware response information
> > > > > between
> > > > > +        * ish_send() and process_recv() callback.
> > > > > +        */
> > > > > +       struct response_info response;
> > > > > +
> > > > > +       struct work_struct work_ishtp_reset;
> > > > > +       struct work_struct work_ec_evt;
> > > > > +       struct cros_ec_device *ec_dev;
> > > > > +};
> > > > > +
> > > > > +/**
> > > > > + * ish_evt_handler - ISH to AP event handler
> > > > > + * @work:              Work struct
> > > > > + */
> > > > > +static void ish_evt_handler(struct work_struct *work)
> > > > > +{
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > +               container_of(work, struct ishtp_cl_data,
> > > > > work_ec_evt);
> > > > > +       struct cros_ec_device *ec_dev = client_data->ec_dev;
> > > > > +
> > > > > +       if (cros_ec_get_next_event(ec_dev, NULL) > 0) {
> > > > > +               blocking_notifier_call_chain(&ec_dev-
> > > > > >event_notifier,
> > > > > +                                            0, ec_dev);
> > > > > +       }
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * ish_send() - Send message from host to firmware
> > > > > + * @client_data:       Client data instance
> > > > > + * @out_msg:           Message buffer to be sent to firmware
> > > > > + * @out_size:          Size of out going message
> > > > > + * @in_msg:            Message buffer where the incoming
> > > > > data copied.
> > > > > + *                     This buffer is allocated by calling
> > > > > + * @in_size:           Max size of incoming message
> > > > > + *
> > > > > + * Return: Number of bytes copied in the in_msg on success,
> > > > > negative
> > > > > + * error code on failure.
> > > > > + */
> > > > > +static int ish_send(struct ishtp_cl_data *client_data,
> > > > > +                   u8 *out_msg, size_t out_size,
> > > > > +                   u8 *in_msg, size_t in_size)
> > > > > +{
> > > > > +       int rv;
> > > > > +       struct header *out_hdr = (struct header *)out_msg;
> > > > > +       struct ishtp_cl *cros_ish_cl = client_data-
> > > > > >cros_ish_cl;
> > > > > +
> > > > > +       dev_dbg(cl_data_to_dev(client_data),
> > > > > +               "%s: channel=%02u status=%02u\n",
> > > > > +               __func__, out_hdr->channel, out_hdr->status);
> > > > > +
> > > > > +       /* Setup for incoming response */
> > > > > +       client_data->response.data = in_msg;
> > > > > +       client_data->response.max_size = in_size;
> > > > > +       client_data->response.error = 0;
> > > > > +       client_data->response.received = false;
> > > > > +
> > > > > +       rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
> > > > > +       if (rv) {
> > > > > +               dev_err(cl_data_to_dev(client_data),
> > > > > +                       "ishtp_cl_send error %d\n", rv);
> > > > > +               return rv;
> > > > > +       }
> > > > > +
> > > > > +       wait_event_interruptible_timeout(client_data-
> > > > > >response.wait_queue,
> > > > > +                                        client_data-
> > > > > >response.received,
> > > > > +                                        ISHTP_SEND_TIMEOUT);
> > > > > +       if (!client_data->response.received) {
> > > > > +               dev_err(cl_data_to_dev(client_data),
> > > > > +                       "Timed out for response to host
> > > > > message\n");
> > > > > +               return -ETIMEDOUT;
> > > > > +       }
> > > > > +
> > > > > +       if (client_data->response.error < 0)
> > > > > +               return client_data->response.error;
> > > > > +
> > > > > +       return client_data->response.size;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * process_recv() -    Received and parse incoming packet
> > > > > + * @cros_ish_cl:       Client instance to get stats
> > > > > + * @rb_in_proc:                Host interface message buffer
> > > > > + *
> > > > > + * Parse the incoming packet. If it is a response packet
> > > > > then it will
> > > > > + * update per instance flags and wake up the caller waiting
> > > > > to for the
> > > > > + * response. If it is an event packet then it will schedule
> > > > > event work.
> > > > > + */
> > > > > +static void process_recv(struct ishtp_cl *cros_ish_cl,
> > > > > +                        struct ishtp_cl_rb *rb_in_proc)
> > > > > +{
> > > > > +       size_t data_len = rb_in_proc->buf_idx;
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > +               ishtp_get_client_data(cros_ish_cl);
> > > > > +       struct device *dev = cl_data_to_dev(client_data);
> > > > > +       struct cros_ish_in_msg *in_msg =
> > > > > +               (struct cros_ish_in_msg *)rb_in_proc-
> > > > > >buffer.data;
> > > > > +
> > > > > +       /* Proceed only if reset or init is not in progress
> > > > > */
> > > > > +       if (!down_read_trylock(&init_lock)) {
> > > > > +               /* Free the buffer */
> > > > > +               ishtp_cl_io_rb_recycle(rb_in_proc);
> > > > > +               dev_warn(dev,
> > > > > +                        "Host is not ready to receive
> > > > > incoming messages\n");
> > > > > +               return;
> > > > > +       }
> > > > > +
> > > > > +       /*
> > > > > +        * All firmware messages contain a header. Check the
> > > > > buffer size
> > > > > +        * before accessing elements inside.
> > > > > +        */
> > > > > +       if (!rb_in_proc->buffer.data) {
> > > > > +               dev_warn(dev, "rb_in_proc->buffer.data
> > > > > returned null");
> > > > > +               client_data->response.error = -EBADMSG;
> > > > > +               goto end_error;
> > > > > +       }
> > > > > +
> > > > > +       if (data_len < sizeof(struct header)) {
> > > > > +               dev_err(dev, "data size %zu is less than
> > > > > header %zu\n",
> > > > > +                       data_len, sizeof(struct header));
> > > > > +               client_data->response.error = -EMSGSIZE;
> > > > > +               goto end_error;
> > > > > +       }
> > > > > +
> > > > > +       dev_dbg(dev, "channel=%02u status=%02u\n",
> > > > > +               in_msg->hdr.channel, in_msg->hdr.status);
> > > > > +
> > > > > +       switch (in_msg->hdr.channel) {
> > > > > +       case CROS_EC_COMMAND:
> > > > > +               /* Sanity check */
> > > > > +               if (!client_data->response.data) {
> > > > > +                       dev_err(dev,
> > > > > +                               "Receiving buffer is null.
> > > > > Should be allocated by calling function\n");
> > > > > +                       client_data->response.error =
> > > > > -EINVAL;
> > > > > +                       goto error_wake_up;
> > > > > +               }
> > > > > +
> > > > > +               if (client_data->response.received) {
> > > > > +                       dev_err(dev,
> > > > > +                               "Previous firmware message
> > > > > not yet processed\n");
> > > > > +                       client_data->response.error =
> > > > > -EINVAL;
> > > > > +                       goto error_wake_up;
> > > > > +               }
> > > > > +
> > > > > +               if (data_len > client_data-
> > > > > >response.max_size) {
> > > > > +                       dev_err(dev,
> > > > > +                               "Received buffer size %zu is
> > > > > larger than allocated buffer %zu\n",
> > > > > +                               data_len, client_data-
> > > > > >response.max_size);
> > > > > +                       client_data->response.error =
> > > > > -EMSGSIZE;
> > > > > +                       goto error_wake_up;
> > > > > +               }
> > > > > +
> > > > > +               if (in_msg->hdr.status) {
> > > > > +                       dev_err(dev, "firmware returned
> > > > > status %d\n",
> > > > > +                               in_msg->hdr.status);
> > > > > +                       client_data->response.error = -EIO;
> > > > > +                       goto error_wake_up;
> > > > > +               }
> > > > > +
> > > > > +               /* Update the actual received buffer size */
> > > > > +               client_data->response.size = data_len;
> > > > > +
> > > > > +               /*
> > > > > +                * Copy the buffer received in firmware
> > > > > response for the
> > > > > +                * calling thread.
> > > > > +                */
> > > > > +               memcpy(client_data->response.data,
> > > > > +                      rb_in_proc->buffer.data, data_len);
> > > > > +
> > > > > +               /* Set flag before waking up the caller */
> > > > > +               client_data->response.received = true;
> > > > > +error_wake_up:
> > > > > +               /* Wake the calling thread */
> > > > > +               wake_up_interruptible(&client_data-
> > > > > >response.wait_queue);
> > > > > +
> > > > > +               break;
> > > > > +
> > > > > +       case CROS_MKBP_EVENT:
> > > > > +               /* The event system doesn't send any data in
> > > > > buffer */
> > > > > +               schedule_work(&client_data->work_ec_evt);
> > > > > +
> > > > > +               break;
> > > > > +
> > > > > +       default:
> > > > > +               dev_err(dev, "Invalid channel=%02d\n",
> > > > > in_msg->hdr.channel);
> > > > > +       }
> > > > > +
> > > > > +end_error:
> > > > > +       /* Free the buffer */
> > > > > +       ishtp_cl_io_rb_recycle(rb_in_proc);
> > > > > +
> > > > > +       up_read(&init_lock);
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * ish_event_cb() - bus driver callback for incoming message
> > > > > + * @cl_device:         ISHTP client device for which this
> > > > > message is
> > > > > + *                     targeted.
> > > > > + *
> > > > > + * Remove the packet from the list and process the message
> > > > > by calling
> > > > > + * process_recv.
> > > > > + */
> > > > > +static void ish_event_cb(struct ishtp_cl_device *cl_device)
> > > > > +{
> > > > > +       struct ishtp_cl_rb *rb_in_proc;
> > > > > +       struct ishtp_cl *cros_ish_cl =
> > > > > ishtp_get_drvdata(cl_device);
> > > > > +
> > > > > +       while ((rb_in_proc = ishtp_cl_rx_get_rb(cros_ish_cl))
> > > > > != NULL) {
> > > > > +               /* Decide what to do with received data */
> > > > > +               process_recv(cros_ish_cl, rb_in_proc);
> > > > > +       }
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ish_init() - Init function for ISHTP client
> > > > > + * @cros_ish_cl:       ISHTP client instance
> > > > > + *
> > > > > + * This function complete the initializtion of the client.
> > > > > + *
> > > > > + * Return: 0 for success, negative error code for failure.
> > > > > + */
> > > > > +static int cros_ish_init(struct ishtp_cl *cros_ish_cl)
> > > > > +{
> > > > > +       int rv;
> > > > > +       struct ishtp_device *dev;
> > > > > +       struct ishtp_fw_client *fw_client;
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > ishtp_get_client_data(cros_ish_cl);
> > > > > +
> > > > > +       rv = ishtp_cl_link(cros_ish_cl);
> > > > > +       if (rv) {
> > > > > +               dev_err(cl_data_to_dev(client_data),
> > > > > +                       "ishtp_cl_link failed\n");
> > > > > +               return rv;
> > > > > +       }
> > > > > +
> > > > > +       dev = ishtp_get_ishtp_device(cros_ish_cl);
> > > > > +
> > > > > +       /* Connect to firmware client */
> > > > > +       ishtp_set_tx_ring_size(cros_ish_cl,
> > > > > CROS_ISH_CL_TX_RING_SIZE);
> > > > > +       ishtp_set_rx_ring_size(cros_ish_cl,
> > > > > CROS_ISH_CL_RX_RING_SIZE);
> > > > > +
> > > > > +       fw_client = ishtp_fw_cl_get_client(dev,
> > > > > &cros_ish_guid);
> > > > > +       if (!fw_client) {
> > > > > +               dev_err(cl_data_to_dev(client_data),
> > > > > +                       "ish client uuid not found\n");
> > > > > +               rv = -ENOENT;
> > > > > +               goto err_cl_unlink;
> > > > > +       }
> > > > > +
> > > > > +       ishtp_cl_set_fw_client_id(cros_ish_cl,
> > > > > +                                 ishtp_get_fw_client_id(fw_c
> > > > > lient));
> > > > > +       ishtp_set_connection_state(cros_ish_cl,
> > > > > ISHTP_CL_CONNECTING);
> > > > > +
> > > > > +       rv = ishtp_cl_connect(cros_ish_cl);
> > > > > +       if (rv) {
> > > > > +               dev_err(cl_data_to_dev(client_data),
> > > > > +                       "client connect fail\n");
> > > > > +               goto err_cl_unlink;
> > > > > +       }
> > > > > +
> > > > > +       ishtp_register_event_cb(client_data->cl_device,
> > > > > ish_event_cb);
> > > > > +       return 0;
> > > > > +
> > > > > +err_cl_unlink:
> > > > > +       ishtp_cl_unlink(cros_ish_cl);
> > > > > +       return rv;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ish_deinit() - Deinit function for ISHTP client
> > > > > + * @cros_ish_cl:       ISHTP client instance
> > > > > + *
> > > > > + * Unlink and free cros_ec client
> > > > > + */
> > > > > +static void cros_ish_deinit(struct ishtp_cl *cros_ish_cl)
> > > > > +{
> > > > > +       ishtp_set_connection_state(cros_ish_cl,
> > > > > ISHTP_CL_DISCONNECTING);
> > > > > +       ishtp_cl_disconnect(cros_ish_cl);
> > > > > +       ishtp_cl_unlink(cros_ish_cl);
> > > > > +       ishtp_cl_flush_queues(cros_ish_cl);
> > > > > +
> > > > > +       /* Disband and free all Tx and Rx client-level rings
> > > > > */
> > > > > +       ishtp_cl_free(cros_ish_cl);
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * prepare_cros_ec_rx() - Check & prepare receive buffer
> > > > > + * @in_msg:            Incoming message buffer
> > > > > + * @cros_ec_command    cros_ec command used to send &
> > > > > receive data
> > > > > + *
> > > > > + * Check the received buffer. Convert to cros_ec_command
> > > > > format.
> > > > > + */
> > > > > +static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
> > > > > +                             const struct cros_ish_in_msg
> > > > > *in_msg,
> > > > > +                             struct cros_ec_command *msg)
> > > > > +{
> > > > > +       u8 sum = 0;
> > > > > +       int i, rv, offset;
> > > > > +
> > > > > +       /* Check response error code */
> > > > > +       msg->result = in_msg->ec_response.result;
> > > > > +       rv = cros_ec_check_result(ec_dev, msg);
> > > > > +       if (rv < 0)
> > > > > +               return rv;
> > > > > +
> > > > > +       if (in_msg->ec_response.data_len > msg->insize) {
> > > > > +               dev_err(ec_dev->dev, "Packet too long (%d
> > > > > bytes, expected %d)",
> > > > > +                       in_msg->ec_response.data_len, msg-
> > > > > >insize);
> > > > > +               return -ENOSPC;
> > > > > +       }
> > > > > +
> > > > > +       /* Copy response packet payload and compute checksum
> > > > > */
> > > > > +       for (i = 0; i < sizeof(struct ec_host_response); i++)
> > > > > +               sum += ((u8
> > > > > *)in_msg)[IN_MSG_EC_RESPONSE_PREAMBLE + i];
> > > > > +
> > > > > +       offset = sizeof(struct cros_ish_in_msg);
> > > > > +       for (i = 0; i < in_msg->ec_response.data_len; i++)
> > > > > +               sum += msg->data[i] = ((u8 *)in_msg)[offset +
> > > > > i];
> > > > > +
> > > > > +       if (sum) {
> > > > > +               dev_dbg(ec_dev->dev, "Bad received packet
> > > > > checksum %d\n", sum);
> > > > > +               return -EBADMSG;
> > > > > +       }
> > > > > +
> > > > > +       return 0;
> > > > > +}
> > > > > +
> > > > > +static int cros_ec_pkt_xfer_ish(struct cros_ec_device
> > > > > *ec_dev,
> > > > > +                               struct cros_ec_command *msg)
> > > > > +{
> > > > > +       int rv;
> > > > > +       struct ishtp_cl *cros_ish_cl = ec_dev->priv;
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > ishtp_get_client_data(cros_ish_cl);
> > > > > +       struct device *dev = cl_data_to_dev(client_data);
> > > > > +       struct cros_ish_in_msg *in_msg = (struct
> > > > > cros_ish_in_msg *)ec_dev->din;
> > > > > +       struct cros_ish_out_msg *out_msg =
> > > > > +               (struct cros_ish_out_msg *)ec_dev->dout;
> > > > > +       size_t in_size = sizeof(struct cros_ish_in_msg) +
> > > > > msg->insize;
> > > > > +       size_t out_size = sizeof(struct cros_ish_out_msg) +
> > > > > msg->outsize;
> > > > > +
> > > > > +       /* Proceed only if reset-init is not in progress */
> > > > > +       if (!down_read_trylock(&init_lock)) {
> > > > > +               dev_warn(dev,
> > > > > +                        "Host is not ready to send messages
> > > > > to ISH. Try again\n");
> > > > > +               return -EAGAIN;
> > > > > +       }
> > > > > +
> > > > > +       /* Sanity checks */
> > > > > +       if (in_size > ec_dev->din_size) {
> > > > > +               dev_err(dev,
> > > > > +                       "Incoming payload size %zu is too
> > > > > large for ec_dev->din_size %d\n",
> > > > > +                       in_size, ec_dev->din_size);
> > > > > +               return -EMSGSIZE;
> > > > > +       }
> > > > > +
> > > > > +       if (out_size > ec_dev->dout_size) {
> > > > > +               dev_err(dev,
> > > > > +                       "Outgoing payload size %zu is too
> > > > > large for ec_dev->dout_size %d\n",
> > > > > +                       out_size, ec_dev->dout_size);
> > > > > +               return -EMSGSIZE;
> > > > > +       }
> > > > > +
> > > > > +       /* Prepare the package to be sent over ISH TP */
> > > > > +       out_msg->hdr.channel = CROS_EC_COMMAND;
> > > > > +       out_msg->hdr.status = 0;
> > > > > +
> > > > > +       ec_dev->dout += OUT_MSG_EC_REQUEST_PREAMBLE;
> > > > > +       cros_ec_prepare_tx(ec_dev, msg);
> > > > > +       ec_dev->dout -= OUT_MSG_EC_REQUEST_PREAMBLE;
> > > > > +
> > > > > +       dev_dbg(dev,
> > > > > +               "out_msg: struct_ver=0x%x checksum=0x%x
> > > > > command=0x%x command_ver=0x%x data_len=0x%x\n",
> > > > > +               out_msg->ec_request.struct_version,
> > > > > +               out_msg->ec_request.checksum,
> > > > > +               out_msg->ec_request.command,
> > > > > +               out_msg->ec_request.command_version,
> > > > > +               out_msg->ec_request.data_len);
> > > > > +
> > > > > +       /* Send command to ISH EC firmware and read response
> > > > > */
> > > > > +       rv = ish_send(client_data,
> > > > > +                     (u8 *)out_msg, out_size,
> > > > > +                     (u8 *)in_msg, in_size);
> > > > > +       if (rv < 0)
> > > > > +               goto end_error;
> > > > > +
> > > > > +       rv = prepare_cros_ec_rx(ec_dev, in_msg, msg);
> > > > > +       if (rv)
> > > > > +               goto end_error;
> > > > > +
> > > > > +       rv = in_msg->ec_response.data_len;
> > > > > +
> > > > > +       dev_dbg(dev,
> > > > > +               "in_msg: struct_ver=0x%x checksum=0x%x
> > > > > result=0x%x data_len=0x%x\n",
> > > > > +               in_msg->ec_response.struct_version,
> > > > > +               in_msg->ec_response.checksum,
> > > > > +               in_msg->ec_response.result,
> > > > > +               in_msg->ec_response.data_len);
> > > > > +
> > > > > +end_error:
> > > > > +       if (msg->command == EC_CMD_REBOOT_EC)
> > > > > +               msleep(EC_REBOOT_DELAY_MS);
> > > > > +
> > > > > +       up_read(&init_lock);
> > > > > +
> > > > > +       return rv;
> > > > > +}
> > > > > +
> > > > > +static int cros_ec_dev_init(struct ishtp_cl_data
> > > > > *client_data)
> > > > > +{
> > > > > +       struct cros_ec_device *ec_dev;
> > > > > +       struct device *dev = cl_data_to_dev(client_data);
> > > > > +
> > > > > +       ec_dev = devm_kzalloc(dev, sizeof(*ec_dev),
> > > > > GFP_KERNEL);
> > > > > +       if (!ec_dev)
> > > > > +               return -ENOMEM;
> > > > > +
> > > > > +       client_data->ec_dev = ec_dev;
> > > > > +       dev->driver_data = ec_dev;
> > > > > +
> > > > > +       ec_dev->dev = dev;
> > > > > +       ec_dev->priv = client_data->cros_ish_cl;
> > > > > +       ec_dev->cmd_xfer = NULL;
> > > > > +       ec_dev->pkt_xfer = cros_ec_pkt_xfer_ish;
> > > > > +       ec_dev->phys_name = dev_name(dev);
> > > > > +       ec_dev->din_size = sizeof(struct cros_ish_in_msg) +
> > > > > +                          sizeof(struct
> > > > > ec_response_get_protocol_info);
> > > > > +       ec_dev->dout_size = sizeof(struct cros_ish_out_msg);
> > > > > +
> > > > > +       return cros_ec_register(ec_dev);
> > > > > +}
> > > > > +
> > > > > +static void reset_handler(struct work_struct *work)
> > > > > +{
> > > > > +       int rv;
> > > > > +       struct device *dev;
> > > > > +       struct ishtp_cl *cros_ish_cl;
> > > > > +       struct ishtp_cl_device *cl_device;
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > +               container_of(work, struct ishtp_cl_data,
> > > > > work_ishtp_reset);
> > > > > +
> > > > > +       /* Lock for reset to complete */
> > > > > +       down_write(&init_lock);
> > > > > +
> > > > > +       cros_ish_cl = client_data->cros_ish_cl;
> > > > > +       cl_device = client_data->cl_device;
> > > > > +
> > > > > +       /* Unlink, flush queues & start again */
> > > > > +       ishtp_cl_unlink(cros_ish_cl);
> > > > > +       ishtp_cl_flush_queues(cros_ish_cl);
> > > > > +       ishtp_cl_free(cros_ish_cl);
> > > > > +
> > > > > +       cros_ish_cl = ishtp_cl_allocate(cl_device);
> > > > > +       if (!cros_ish_cl) {
> > > > > +               up_write(&init_lock);
> > > > > +               return;
> > > > > +       }
> > > > > +
> > > > > +       ishtp_set_drvdata(cl_device, cros_ish_cl);
> > > > > +       ishtp_set_client_data(cros_ish_cl, client_data);
> > > > > +       client_data->cros_ish_cl = cros_ish_cl;
> > > > > +
> > > > > +       rv = cros_ish_init(cros_ish_cl);
> > > > > +       if (rv) {
> > > > > +               ishtp_cl_free(cros_ish_cl);
> > > > > +               dev_err(cl_data_to_dev(client_data), "Reset
> > > > > Failed\n");
> > > > > +               up_write(&init_lock);
> > > > > +               return;
> > > > > +       }
> > > > > +
> > > > > +       /* Refresh ec_dev device pointers */
> > > > > +       client_data->ec_dev->priv = client_data->cros_ish_cl;
> > > > > +       dev = cl_data_to_dev(client_data);
> > > > > +       dev->driver_data = client_data->ec_dev;
> > > > > +
> > > > > +       dev_info(cl_data_to_dev(client_data), "Chrome EC ISH
> > > > > reset done\n");
> > > > > +
> > > > > +       up_write(&init_lock);
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ec_ishtp_probe() - ISHTP client driver probe
> > > > > callback
> > > > > + * @cl_device:         ISHTP client device instance
> > > > > + *
> > > > > + * Return: 0 for success, negative error code for failure.
> > > > > + */
> > > > > +static int cros_ec_ishtp_probe(struct ishtp_cl_device
> > > > > *cl_device)
> > > > > +{
> > > > > +       int rv;
> > > > > +       struct ishtp_cl *cros_ish_cl;
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > +               devm_kzalloc(ishtp_device(cl_device),
> > > > > +                            sizeof(*client_data),
> > > > > GFP_KERNEL);
> > > > > +       if (!client_data)
> > > > > +               return -ENOMEM;
> > > > > +
> > > > > +       /* Lock for initialization to complete */
> > > > > +       down_write(&init_lock);
> > > > > +
> > > > > +       cros_ish_cl = ishtp_cl_allocate(cl_device);
> > > > > +       if (!cros_ish_cl) {
> > > > > +               rv = -ENOMEM;
> > > > > +               goto end_ishtp_cl_alloc_error;
> > > > > +       }
> > > > > +
> > > > > +       ishtp_set_drvdata(cl_device, cros_ish_cl);
> > > > > +       ishtp_set_client_data(cros_ish_cl, client_data);
> > > > > +       client_data->cros_ish_cl = cros_ish_cl;
> > > > > +       client_data->cl_device = cl_device;
> > > > > +
> > > > > +       init_waitqueue_head(&client_data-
> > > > > >response.wait_queue);
> > > > > +
> > > > > +       INIT_WORK(&client_data->work_ishtp_reset,
> > > > > +                 reset_handler);
> > > > > +       INIT_WORK(&client_data->work_ec_evt,
> > > > > +                 ish_evt_handler);
> > > > > +
> > > > > +       rv = cros_ish_init(cros_ish_cl);
> > > > > +       if (rv)
> > > > > +               goto end_ishtp_cl_init_error;
> > > > > +
> > > > > +       ishtp_get_device(cl_device);
> > > > > +
> > > > > +       up_write(&init_lock);
> > > > > +
> > > > > +       /* Register croc_ec_dev mfd */
> > > > > +       rv = cros_ec_dev_init(client_data);
> > > > > +       if (rv)
> > > > > +               goto end_cros_ec_dev_init_error;
> > > > > +
> > > > > +       return 0;
> > > > > +
> > > > > +end_cros_ec_dev_init_error:
> > > > > +       ishtp_set_connection_state(cros_ish_cl,
> > > > > ISHTP_CL_DISCONNECTING);
> > > > > +       ishtp_cl_disconnect(cros_ish_cl);
> > > > > +       ishtp_cl_unlink(cros_ish_cl);
> > > > > +       ishtp_cl_flush_queues(cros_ish_cl);
> > > > > +       ishtp_put_device(cl_device);
> > > > > +end_ishtp_cl_init_error:
> > > > > +       ishtp_cl_free(cros_ish_cl);
> > > > > +end_ishtp_cl_alloc_error:
> > > > > +       up_write(&init_lock);
> > > > > +       return rv;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ec_ishtp_remove() - ISHTP client driver remove
> > > > > callback
> > > > > + * @cl_device:         ISHTP client device instance
> > > > > + *
> > > > > + * Return: 0
> > > > > + */
> > > > > +static int cros_ec_ishtp_remove(struct ishtp_cl_device
> > > > > *cl_device)
> > > > > +{
> > > > > +       struct ishtp_cl *cros_ish_cl =
> > > > > ishtp_get_drvdata(cl_device);
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > ishtp_get_client_data(cros_ish_cl);
> > > > > +
> > > > > +       cancel_work_sync(&client_data->work_ishtp_reset);
> > > > > +       cancel_work_sync(&client_data->work_ec_evt);
> > > > > +       cros_ish_deinit(cros_ish_cl);
> > > > > +       ishtp_put_device(cl_device);
> > > > > +
> > > > > +       return 0;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ec_ishtp_reset() - ISHTP client driver reset
> > > > > callback
> > > > > + * @cl_device:         ISHTP client device instance
> > > > > + *
> > > > > + * Return: 0
> > > > > + */
> > > > > +static int cros_ec_ishtp_reset(struct ishtp_cl_device
> > > > > *cl_device)
> > > > > +{
> > > > > +       struct ishtp_cl *cros_ish_cl =
> > > > > ishtp_get_drvdata(cl_device);
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > ishtp_get_client_data(cros_ish_cl);
> > > > > +
> > > > > +       schedule_work(&client_data->work_ishtp_reset);
> > > > > +
> > > > > +       return 0;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ec_ishtp_suspend() - ISHTP client driver suspend
> > > > > callback
> > > > > + * @device:    device instance
> > > > > + *
> > > > > + * Return: 0 for success, negative error code for failure.
> > > > > + */
> > > > > +static int __maybe_unused cros_ec_ishtp_suspend(struct
> > > > > device *device)
> > > > > +{
> > > > > +       struct ishtp_cl_device *cl_device =
> > > > > dev_get_drvdata(device);
> > > > > +       struct ishtp_cl *cros_ish_cl =
> > > > > ishtp_get_drvdata(cl_device);
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > ishtp_get_client_data(cros_ish_cl);
> > > > > +
> > > > > +       return cros_ec_suspend(client_data->ec_dev);
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * cros_ec_ishtp_resume() - ISHTP client driver resume
> > > > > callback
> > > > > + * @device:    device instance
> > > > > + *
> > > > > + * Return: 0 for success, negative error code for failure.
> > > > > + */
> > > > > +static int __maybe_unused cros_ec_ishtp_resume(struct device
> > > > > *device)
> > > > > +{
> > > > > +       struct ishtp_cl_device *cl_device =
> > > > > dev_get_drvdata(device);
> > > > > +       struct ishtp_cl *cros_ish_cl =
> > > > > ishtp_get_drvdata(cl_device);
> > > > > +       struct ishtp_cl_data *client_data =
> > > > > ishtp_get_client_data(cros_ish_cl);
> > > > > +
> > > > > +       return cros_ec_resume(client_data->ec_dev);
> > > > > +}
> > > > > +
> > > > > +static SIMPLE_DEV_PM_OPS(cros_ec_ishtp_pm_ops,
> > > > > cros_ec_ishtp_suspend,
> > > > > +                        cros_ec_ishtp_resume);
> > > > > +
> > > > > +static struct ishtp_cl_driver  cros_ec_ishtp_driver = {
> > > > > +       .name = "cros_ec_ishtp",
> > > > > +       .guid = &cros_ish_guid,
> > > > > +       .probe = cros_ec_ishtp_probe,
> > > > > +       .remove = cros_ec_ishtp_remove,
> > > > > +       .reset = cros_ec_ishtp_reset,
> > > > > +       .driver = {
> > > > > +               .pm = &cros_ec_ishtp_pm_ops,
> > > > > +       },
> > > > > +};
> > > > > +
> > > > > +static int __init cros_ec_ishtp_mod_init(void)
> > > > > +{
> > > > > +       return
> > > > > ishtp_cl_driver_register(&cros_ec_ishtp_driver, THIS_MODULE);
> > > > > +}
> > > > > +
> > > > > +static void __exit cros_ec_ishtp_mod_exit(void)
> > > > > +{
> > > > > +       ishtp_cl_driver_unregister(&cros_ec_ishtp_driver);
> > > > > +}
> > > > > +
> > > > > +module_init(cros_ec_ishtp_mod_init);
> > > > > +module_exit(cros_ec_ishtp_mod_exit);
> > > > > +
> > > > > +MODULE_DESCRIPTION("ChromeOS EC ISHTP Client Driver");
> > > > > +MODULE_AUTHOR("Rushikesh S Kadam <
> > > > > rushikesh.s.kadam@intel.com>");
> > > > > +
> > > > > +MODULE_LICENSE("GPL v2");
> > > > > +MODULE_ALIAS("ishtp:*");
> > > > > --
> > > > > 1.9.1
> > > > > 

Re: [PATCH v3] platform: chrome: Add ChromeOS EC ISHTP driver

[Enric Balletbo i Serra]

Hi,

On 12/4/19 17:22, Srinivas Pandruvada wrote:
> On Thu, 2019-04-11 at 15:54 +0200, Enric Balletbo i Serra wrote:
>> Hi,
>>
>> On 11/4/19 13:10, Rushikesh S Kadam wrote:
>>> Hi Enric, Srinivas
>>>
>>> On Thu, Apr 11, 2019 at 12:55:13PM +0200, Enric Balletbo i Serra
>>> wrote:
>>>> Hi,
>>>>
>>>> On 10/4/19 17:31, Jett Rink wrote:
>>>>> Reviewed-by: Jett Rink <jettrink@chromium.org>
>>>>> Tested-by: Jett Rink <jettrink@chromium.org>
>>>>>
>>>>>
>>>>> On Sun, Apr 7, 2019 at 6:10 AM Rushikesh S Kadam
>>>>> <rushikesh.s.kadam@intel.com> wrote:
>>>>>>
>>>>>> This driver implements a slim layer to enable the ChromeOS
>>>>>> EC kernel stack (cros_ec) to communicate with ChromeOS EC
>>>>>> firmware running on the Intel Integrated Sensor Hub (ISH).
>>>>>>
>>>>>> The driver registers a ChromeOS EC MFD device to connect
>>>>>> with cros_ec kernel stack (upper layer), and it registers a
>>>>>> client with the ISH Transport Protocol bus (lower layer) to
>>>>>> talk with the ISH firwmare. See description of the ISHTP
>>>>>> protocol at Documentation/hid/intel-ish-hid.txt
>>>>>>
>>>>>> Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com
>>>>>>>
>>>>>> ---
>>>>>>
>>>>>> v3
>>>>>>  - Made several changes to improve code readability. Replaced
>>>>>>    multiple cl_data_to_dev(client_data) with dev variable.
>>>>>> Use
>>>>>>    reverse Xmas tree for variable defintion where it made
>>>>>> sense.
>>>>>>    Dropped few debug prints. Add docstring for function
>>>>>>    prepare_cros_ec_rx().
>>>>>>  - Fix code in function prepare_cros_ec_rx() under label
>>>>>>    end_cros_ec_dev_init_error.
>>>>>>  - Recycle buffer in process_recv() on failing to obtain the
>>>>>>    semaphore.
>>>>>>  - Increase ISHTP TX/RX ring buffer size to 8.
>>>>>>  - Alphabetically ordered CROS_EC_ISHTP entries in Makefile
>>>>>> and
>>>>>>    Kconfig.
>>>>>>  - Updated commit message.
>>>>>>
>>>>>> v2
>>>>>>  - Dropped unused "reset" parameter in function
>>>>>> cros_ec_init()
>>>>>>  - Change driver name to cros_ec_ishtp to be consistent with
>>>>>> other
>>>>>>    references in the code.
>>>>>>  - Fixed a few typos.
>>>>>>
>>>>>> v1
>>>>>>  - Initial version
>>>>>>
>>>>>>  drivers/platform/chrome/Kconfig         |  13 +
>>>>>>  drivers/platform/chrome/Makefile        |   1 +
>>>>>>  drivers/platform/chrome/cros_ec_ishtp.c | 765
>>>>>> ++++++++++++++++++++++++++++++++
>>>>>>  3 files changed, 779 insertions(+)
>>>>>>  create mode 100644 drivers/platform/chrome/cros_ec_ishtp.c
>>>>>>
>>>>>> diff --git a/drivers/platform/chrome/Kconfig
>>>>>> b/drivers/platform/chrome/Kconfig
>>>>>> index 16b1615..5848179 100644
>>>>>> --- a/drivers/platform/chrome/Kconfig
>>>>>> +++ b/drivers/platform/chrome/Kconfig
>>>>>> @@ -62,6 +62,19 @@ config CROS_EC_I2C
>>>>>>           a checksum. Failing accesses will be retried three
>>>>>> times to
>>>>>>           improve reliability.
>>>>>>
>>>>>> +config CROS_EC_ISHTP
>>>>>> +       tristate "ChromeOS Embedded Controller (ISHTP)"
>>>>>> +       depends on MFD_CROS_EC
>>>>>> +       depends on INTEL_ISH_HID
>>>>>> +       help
>>>>>> +         If you say Y here, you get support for talking to
>>>>>> the ChromeOS EC
>>>>>> +         firmware running on Intel Integrated Sensor Hub
>>>>>> (ISH), using the
>>>>>> +         ISH Transport protocol (ISH-TP). This uses a simple
>>>>>> byte-level
>>>>>> +         protocol with a checksum.
>>>>>> +
>>>>>> +         To compile this driver as a module, choose M here:
>>>>>> the
>>>>>> +         module will be called cros_ec_ishtp.
>>>>>> +
>>>>>>  config CROS_EC_SPI
>>>>>>         tristate "ChromeOS Embedded Controller (SPI)"
>>>>>>         depends on MFD_CROS_EC && SPI
>>>>>> diff --git a/drivers/platform/chrome/Makefile
>>>>>> b/drivers/platform/chrome/Makefile
>>>>>> index cd591bf..4efe102 100644
>>>>>> --- a/drivers/platform/chrome/Makefile
>>>>>> +++ b/drivers/platform/chrome/Makefile
>>>>>> @@ -7,6 +7,7 @@ cros_ec_ctl-objs                        :=
>>>>>> cros_ec_sysfs.o cros_ec_lightbar.o \
>>>>>>                                            cros_ec_vbc.o
>>>>>> cros_ec_debugfs.o
>>>>>>  obj-$(CONFIG_CROS_EC_CTL)              += cros_ec_ctl.o
>>>>>>  obj-$(CONFIG_CROS_EC_I2C)              += cros_ec_i2c.o
>>>>>> +obj-$(CONFIG_CROS_EC_ISHTP)            += cros_ec_ishtp.o
>>>>>>  obj-$(CONFIG_CROS_EC_SPI)              += cros_ec_spi.o
>>>>>>  cros_ec_lpcs-objs                      := cros_ec_lpc.o
>>>>>> cros_ec_lpc_reg.o
>>>>>>  cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC) += cros_ec_lpc_mec.o
>>>>>> diff --git a/drivers/platform/chrome/cros_ec_ishtp.c
>>>>>> b/drivers/platform/chrome/cros_ec_ishtp.c
>>>>>> new file mode 100644
>>>>>> index 0000000..b1d19c4
>>>>>> --- /dev/null
>>>>>> +++ b/drivers/platform/chrome/cros_ec_ishtp.c
>>>>>> @@ -0,0 +1,765 @@
>>>>>> +// SPDX-License-Identifier: GPL-2.0
>>>>>> +/*
>>>>>> + * ISHTP client driver for talking to the Chrome OS EC
>>>>>> firmware running
>>>>>> + * on Intel Integrated Sensor Hub (ISH) using the ISH
>>>>>> Transport protocol
>>>>>> + * (ISH-TP).
>>>>>> + *
>>>>>> + * Copyright (c) 2019, Intel Corporation.
>>>>>> + */
>>>>>> +
>>>>>> +#include <linux/delay.h>
>>>>>> +#include <linux/mfd/core.h>
>>>>>> +#include <linux/mfd/cros_ec.h>
>>>>>> +#include <linux/mfd/cros_ec_commands.h>
>>>>>> +#include <linux/module.h>
>>>>>> +#include <linux/pci.h>
>>>>>> +#include <linux/intel-ish-client-if.h>
>>>>>> +
>>>>
>>>> I think that this patch depends on another patchset that's in
>>>> linux-next but
>>>> diddn't land yet to mainline. Do you know if the dependencies are
>>>> queued for
>>>> next merge window? Can you provide the exact patches that this
>>>> patch depends on?
>>>
>>> Enric, 
>>> Sorry I missed mentioning this. 
>>>  
>>> The patch have dependency on intel-ish-hid stack on hid git tree,
>>> branch for-5.2/ish
>>>
> https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git/log/?h=for-5.2/ish
>>>
>>> Srinivas, 
>>> Could you tell if the patches are queued for next merge window?
>>>
> Yes they are queued up for the next merge window. They are already in
> linux-next. One option is to check if Jiri pick this patch as part of
> his pull request. I am assuming that this patch doesn't depend on any
> other ChromeOS EC patches.
> 

Ok, in such case a v4 will be needed, just few style changes that was thinking
to change myself if had the patch had gone through the platform tree.

Thanks,
 Enric

Re: [PATCH v3] platform: chrome: Add ChromeOS EC ISHTP driver

[Enric Balletbo i Serra]

Hi Rushikesh,

Just few style comments and this can go throught the hid tree.

On 7/4/19 14:10, Rushikesh S Kadam wrote:
> This driver implements a slim layer to enable the ChromeOS
> EC kernel stack (cros_ec) to communicate with ChromeOS EC
> firmware running on the Intel Integrated Sensor Hub (ISH).
> 
> The driver registers a ChromeOS EC MFD device to connect
> with cros_ec kernel stack (upper layer), and it registers a
> client with the ISH Transport Protocol bus (lower layer) to
> talk with the ISH firwmare. See description of the ISHTP
> protocol at Documentation/hid/intel-ish-hid.txt
> 
> Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
> ---
> 
> v3
>  - Made several changes to improve code readability. Replaced
>    multiple cl_data_to_dev(client_data) with dev variable. Use
>    reverse Xmas tree for variable defintion where it made sense.
>    Dropped few debug prints. Add docstring for function
>    prepare_cros_ec_rx().
>  - Fix code in function prepare_cros_ec_rx() under label
>    end_cros_ec_dev_init_error.
>  - Recycle buffer in process_recv() on failing to obtain the
>    semaphore.
>  - Increase ISHTP TX/RX ring buffer size to 8.
>  - Alphabetically ordered CROS_EC_ISHTP entries in Makefile and
>    Kconfig.
>  - Updated commit message.
> 
> v2
>  - Dropped unused "reset" parameter in function cros_ec_init()
>  - Change driver name to cros_ec_ishtp to be consistent with other
>    references in the code.
>  - Fixed a few typos. 
> 
> v1
>  - Initial version
> 
>  drivers/platform/chrome/Kconfig         |  13 +
>  drivers/platform/chrome/Makefile        |   1 +
>  drivers/platform/chrome/cros_ec_ishtp.c | 765 ++++++++++++++++++++++++++++++++
>  3 files changed, 779 insertions(+)
>  create mode 100644 drivers/platform/chrome/cros_ec_ishtp.c
> 
> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> index 16b1615..5848179 100644
> --- a/drivers/platform/chrome/Kconfig
> +++ b/drivers/platform/chrome/Kconfig
> @@ -62,6 +62,19 @@ config CROS_EC_I2C
>  	  a checksum. Failing accesses will be retried three times to
>  	  improve reliability.
>  
> +config CROS_EC_ISHTP
> +	tristate "ChromeOS Embedded Controller (ISHTP)"
> +	depends on MFD_CROS_EC
> +	depends on INTEL_ISH_HID
> +	help
> +	  If you say Y here, you get support for talking to the ChromeOS EC
> +	  firmware running on Intel Integrated Sensor Hub (ISH), using the
> +	  ISH Transport protocol (ISH-TP). This uses a simple byte-level
> +	  protocol with a checksum.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called cros_ec_ishtp.
> +
>  config CROS_EC_SPI
>  	tristate "ChromeOS Embedded Controller (SPI)"
>  	depends on MFD_CROS_EC && SPI
> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> index cd591bf..4efe102 100644
> --- a/drivers/platform/chrome/Makefile
> +++ b/drivers/platform/chrome/Makefile
> @@ -7,6 +7,7 @@ cros_ec_ctl-objs			:= cros_ec_sysfs.o cros_ec_lightbar.o \
>  					   cros_ec_vbc.o cros_ec_debugfs.o
>  obj-$(CONFIG_CROS_EC_CTL)		+= cros_ec_ctl.o
>  obj-$(CONFIG_CROS_EC_I2C)		+= cros_ec_i2c.o
> +obj-$(CONFIG_CROS_EC_ISHTP)		+= cros_ec_ishtp.o
>  obj-$(CONFIG_CROS_EC_SPI)		+= cros_ec_spi.o
>  cros_ec_lpcs-objs			:= cros_ec_lpc.o cros_ec_lpc_reg.o
>  cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC)	+= cros_ec_lpc_mec.o
> diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c
> new file mode 100644
> index 0000000..b1d19c4
> --- /dev/null
> +++ b/drivers/platform/chrome/cros_ec_ishtp.c
> @@ -0,0 +1,765 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ISHTP client driver for talking to the Chrome OS EC firmware running
> + * on Intel Integrated Sensor Hub (ISH) using the ISH Transport protocol
> + * (ISH-TP).
> + *
> + * Copyright (c) 2019, Intel Corporation.
> + */
> +

To be coherent with the other cros_ec_* files, please use the c++ style as follows

// SPDX-License-Identifier: GPL-2.0
// ISHTP interface for ChromeOS Embedded Controller
//
// Copyright (c) 2019, Intel Corporation.
//
// ISHTP client driver for talking to the Chrome OS EC firmware running
// on Intel Integrated Sensor Hub (ISH) using the ISH Transport protocol
// (ISH-TP).


> +#include <linux/delay.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/cros_ec.h>
> +#include <linux/mfd/cros_ec_commands.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/intel-ish-client-if.h>
> +
> +/*
> + * ISH TX/RX ring buffer pool size
> + *
> + * The AP->ISH messages and corresponding ISH->AP responses are
> + * serialized. We need 1 TX and 1 RX buffer for these.
> + *
> + * The MKBP ISH->AP events are serialized. We need one additional RX
> + * buffer for them.
> + */
> +#define CROS_ISH_CL_TX_RING_SIZE		8
> +#define CROS_ISH_CL_RX_RING_SIZE		8
> +
> +/* ISH CrOS EC Host Commands */
> +enum cros_ec_ish_channel {
> +	CROS_EC_COMMAND = 1,			/* AP->ISH message */
> +	CROS_MKBP_EVENT = 2,			/* ISH->AP events */
> +};
> +
> +/*
> + * ISH firmware timeout for 1 message send failure is 1Hz, and the
> + * firmware will retry 2 times, so 3Hz is used for timeout.
> + */
> +#define ISHTP_SEND_TIMEOUT			(3 * HZ)
> +
> +/* ISH Transport CrOS EC ISH client unique GUID */
> +static const guid_t cros_ish_guid =
> +	GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
> +		  0xb0, 0xd8, 0x9e, 0x7c, 0xda,	0xe0, 0xd6, 0xa0);
> +
> +struct header {
> +	u8 channel;
> +	u8 status;
> +	u8 reserved[2];
> +} __packed;
> +
> +struct cros_ish_out_msg {
> +	struct header hdr;
> +	struct ec_host_request ec_request;
> +} __packed;
> +
> +struct cros_ish_in_msg {
> +	struct header hdr;
> +	struct ec_host_response ec_response;
> +} __packed;
> +
> +#define IN_MSG_EC_RESPONSE_PREAMBLE					\
> +	offsetof(struct cros_ish_in_msg, ec_response)
> +
> +#define OUT_MSG_EC_REQUEST_PREAMBLE					\
> +	offsetof(struct cros_ish_out_msg, ec_request)
> +
> +#define cl_data_to_dev(client_data) ishtp_device((client_data)->cl_device)
> +
> +/*
> + * The Read-Write Semaphore is used to prevent message TX or RX while
> + * the ishtp client is being initialized or undergoing reset.
> + *
> + * The readers are the kernel function calls responsible for IA->ISH
> + * and ISH->AP messaging.
> + *
> + * The writers are .reset() and .probe() function.
> + */
> +DECLARE_RWSEM(init_lock);
> +
> +/**
> + * struct response_info - Encapsulate firmware response related
> + *			information for passing between function
> + *			ish_send() and process_recv() callback.
> + * @data:		Copy the data received from firmware here.

For all documentation use just one space instead of tabs

@data: Copy ...

> + * @max_size:		Max size allocated for the @data buffer. If the

So we don't have these weirds alignments

@max_size: Max ...

> + *			received data exceeds this value, we log an
> + *			error.
> + * @size:		Actual size of data received from firmware.
> + * @error:		0 for success, negative error code for a
> + *			failure in function process_recv().
> + * @received:		Set to true on receiving a valid firmware
> + *			response to host command
> + * @wait_queue:		Wait queue for Host firmware loading where the
> + *			client sends message to ISH firmware and waits
> + *			for response
> + */
> +struct response_info {
> +	void *data;
> +	size_t max_size;
> +	size_t size;
> +	int error;
> +	bool received;
> +	wait_queue_head_t wait_queue;
> +};
> +
> +/**
> + * struct ishtp_cl_data - Encapsulate per ISH TP Client.
> + * @cros_ish_cl:	ISHTP firmware client instance.
> + * @cl_device:		ISHTP client device instance.
> + * @response:		Firmware response information for passing
> + *			between function ish_send() and process_recv()
> + *			callback.
> + * @work_ishtp_reset:	Work queue reset handling.
> + * @work_ec_evt:	Work queue for EC events.
> + * @ec_dev:		CrOS EC MFD device.
> + *
> + * This structure is used to store per client data.
> + */
> +struct ishtp_cl_data {
> +	struct ishtp_cl *cros_ish_cl;
> +	struct ishtp_cl_device *cl_device;
> +
> +	/*
> +	 * Used for passing firmware response information between
> +	 * ish_send() and process_recv() callback.
> +	 */
> +	struct response_info response;
> +
> +	struct work_struct work_ishtp_reset;
> +	struct work_struct work_ec_evt;
> +	struct cros_ec_device *ec_dev;
> +};
> +
> +/**
> + * ish_evt_handler - ISH to AP event handler
> + * @work:		Work struct
> + */
> +static void ish_evt_handler(struct work_struct *work)
> +{
> +	struct ishtp_cl_data *client_data =
> +		container_of(work, struct ishtp_cl_data, work_ec_evt);
> +	struct cros_ec_device *ec_dev = client_data->ec_dev;
> +
> +	if (cros_ec_get_next_event(ec_dev, NULL) > 0) {
> +		blocking_notifier_call_chain(&ec_dev->event_notifier,
> +					     0, ec_dev);
> +	}
> +}
> +
> +/**
> + * ish_send() - Send message from host to firmware
> + * @client_data:	Client data instance
> + * @out_msg:		Message buffer to be sent to firmware
> + * @out_size:		Size of out going message
> + * @in_msg:		Message buffer where the incoming data copied.
> + *			This buffer is allocated by calling
> + * @in_size:		Max size of incoming message
> + *
> + * Return: Number of bytes copied in the in_msg on success, negative
> + * error code on failure.
> + */
> +static int ish_send(struct ishtp_cl_data *client_data,
> +		    u8 *out_msg, size_t out_size,
> +		    u8 *in_msg, size_t in_size)
> +{
> +	int rv;
> +	struct header *out_hdr = (struct header *)out_msg;
> +	struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl;
> +
> +	dev_dbg(cl_data_to_dev(client_data),
> +		"%s: channel=%02u status=%02u\n",
> +		__func__, out_hdr->channel, out_hdr->status);
> +
> +	/* Setup for incoming response */
> +	client_data->response.data = in_msg;
> +	client_data->response.max_size = in_size;
> +	client_data->response.error = 0;
> +	client_data->response.received = false;
> +
> +	rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
> +	if (rv) {
> +		dev_err(cl_data_to_dev(client_data),
> +			"ishtp_cl_send error %d\n", rv);
> +		return rv;
> +	}
> +
> +	wait_event_interruptible_timeout(client_data->response.wait_queue,
> +					 client_data->response.received,
> +					 ISHTP_SEND_TIMEOUT);
> +	if (!client_data->response.received) {
> +		dev_err(cl_data_to_dev(client_data),
> +			"Timed out for response to host message\n");
> +		return -ETIMEDOUT;
> +	}
> +
> +	if (client_data->response.error < 0)
> +		return client_data->response.error;
> +
> +	return client_data->response.size;
> +}
> +
> +/**
> + * process_recv() -	Received and parse incoming packet
> + * @cros_ish_cl:	Client instance to get stats
> + * @rb_in_proc:		Host interface message buffer
> + *
> + * Parse the incoming packet. If it is a response packet then it will
> + * update per instance flags and wake up the caller waiting to for the
> + * response. If it is an event packet then it will schedule event work.
> + */
> +static void process_recv(struct ishtp_cl *cros_ish_cl,
> +			 struct ishtp_cl_rb *rb_in_proc)
> +{
> +	size_t data_len = rb_in_proc->buf_idx;
> +	struct ishtp_cl_data *client_data =
> +		ishtp_get_client_data(cros_ish_cl);
> +	struct device *dev = cl_data_to_dev(client_data);
> +	struct cros_ish_in_msg *in_msg =
> +		(struct cros_ish_in_msg *)rb_in_proc->buffer.data;
> +
> +	/* Proceed only if reset or init is not in progress */
> +	if (!down_read_trylock(&init_lock)) {
> +		/* Free the buffer */
> +		ishtp_cl_io_rb_recycle(rb_in_proc);
> +		dev_warn(dev,
> +			 "Host is not ready to receive incoming messages\n");
> +		return;
> +	}
> +
> +	/*
> +	 * All firmware messages contain a header. Check the buffer size
> +	 * before accessing elements inside.
> +	 */
> +	if (!rb_in_proc->buffer.data) {
> +		dev_warn(dev, "rb_in_proc->buffer.data returned null");
> +		client_data->response.error = -EBADMSG;
> +		goto end_error;
> +	}
> +
> +	if (data_len < sizeof(struct header)) {
> +		dev_err(dev, "data size %zu is less than header %zu\n",
> +			data_len, sizeof(struct header));
> +		client_data->response.error = -EMSGSIZE;
> +		goto end_error;
> +	}
> +
> +	dev_dbg(dev, "channel=%02u status=%02u\n",
> +		in_msg->hdr.channel, in_msg->hdr.status);
> +
> +	switch (in_msg->hdr.channel) {
> +	case CROS_EC_COMMAND:
> +		/* Sanity check */
> +		if (!client_data->response.data) {
> +			dev_err(dev,
> +				"Receiving buffer is null. Should be allocated by calling function\n");
> +			client_data->response.error = -EINVAL;
> +			goto error_wake_up;
> +		}
> +
> +		if (client_data->response.received) {
> +			dev_err(dev,
> +				"Previous firmware message not yet processed\n");
> +			client_data->response.error = -EINVAL;
> +			goto error_wake_up;
> +		}
> +
> +		if (data_len > client_data->response.max_size) {
> +			dev_err(dev,
> +				"Received buffer size %zu is larger than allocated buffer %zu\n",
> +				data_len, client_data->response.max_size);
> +			client_data->response.error = -EMSGSIZE;
> +			goto error_wake_up;
> +		}
> +
> +		if (in_msg->hdr.status) {
> +			dev_err(dev, "firmware returned status %d\n",
> +				in_msg->hdr.status);
> +			client_data->response.error = -EIO;
> +			goto error_wake_up;
> +		}
> +
> +		/* Update the actual received buffer size */
> +		client_data->response.size = data_len;
> +
> +		/*
> +		 * Copy the buffer received in firmware response for the
> +		 * calling thread.
> +		 */
> +		memcpy(client_data->response.data,
> +		       rb_in_proc->buffer.data, data_len);
> +
> +		/* Set flag before waking up the caller */
> +		client_data->response.received = true;
> +error_wake_up:
> +		/* Wake the calling thread */
> +		wake_up_interruptible(&client_data->response.wait_queue);
> +
> +		break;
> +
> +	case CROS_MKBP_EVENT:
> +		/* The event system doesn't send any data in buffer */
> +		schedule_work(&client_data->work_ec_evt);
> +
> +		break;
> +
> +	default:
> +		dev_err(dev, "Invalid channel=%02d\n", in_msg->hdr.channel);
> +	}
> +
> +end_error:
> +	/* Free the buffer */
> +	ishtp_cl_io_rb_recycle(rb_in_proc);
> +
> +	up_read(&init_lock);
> +}
> +
> +/**
> + * ish_event_cb() - bus driver callback for incoming message
> + * @cl_device:		ISHTP client device for which this message is
> + *			targeted.
> + *
> + * Remove the packet from the list and process the message by calling
> + * process_recv.
> + */
> +static void ish_event_cb(struct ishtp_cl_device *cl_device)
> +{
> +	struct ishtp_cl_rb *rb_in_proc;
> +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> +
> +	while ((rb_in_proc = ishtp_cl_rx_get_rb(cros_ish_cl)) != NULL) {
> +		/* Decide what to do with received data */
> +		process_recv(cros_ish_cl, rb_in_proc);
> +	}
> +}
> +
> +/**
> + * cros_ish_init() - Init function for ISHTP client
> + * @cros_ish_cl:	ISHTP client instance
> + *
> + * This function complete the initializtion of the client.
> + *
> + * Return: 0 for success, negative error code for failure.
> + */
> +static int cros_ish_init(struct ishtp_cl *cros_ish_cl)
> +{
> +	int rv;
> +	struct ishtp_device *dev;
> +	struct ishtp_fw_client *fw_client;
> +	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +	rv = ishtp_cl_link(cros_ish_cl);
> +	if (rv) {
> +		dev_err(cl_data_to_dev(client_data),
> +			"ishtp_cl_link failed\n");
> +		return rv;
> +	}
> +
> +	dev = ishtp_get_ishtp_device(cros_ish_cl);
> +
> +	/* Connect to firmware client */
> +	ishtp_set_tx_ring_size(cros_ish_cl, CROS_ISH_CL_TX_RING_SIZE);
> +	ishtp_set_rx_ring_size(cros_ish_cl, CROS_ISH_CL_RX_RING_SIZE);
> +
> +	fw_client = ishtp_fw_cl_get_client(dev, &cros_ish_guid);
> +	if (!fw_client) {
> +		dev_err(cl_data_to_dev(client_data),
> +			"ish client uuid not found\n");
> +		rv = -ENOENT;
> +		goto err_cl_unlink;
> +	}
> +
> +	ishtp_cl_set_fw_client_id(cros_ish_cl,
> +				  ishtp_get_fw_client_id(fw_client));
> +	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_CONNECTING);
> +
> +	rv = ishtp_cl_connect(cros_ish_cl);
> +	if (rv) {
> +		dev_err(cl_data_to_dev(client_data),
> +			"client connect fail\n");
> +		goto err_cl_unlink;
> +	}
> +
> +	ishtp_register_event_cb(client_data->cl_device, ish_event_cb);
> +	return 0;
> +
> +err_cl_unlink:
> +	ishtp_cl_unlink(cros_ish_cl);
> +	return rv;
> +}
> +
> +/**
> + * cros_ish_deinit() - Deinit function for ISHTP client
> + * @cros_ish_cl:	ISHTP client instance
> + *
> + * Unlink and free cros_ec client
> + */
> +static void cros_ish_deinit(struct ishtp_cl *cros_ish_cl)
> +{
> +	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
> +	ishtp_cl_disconnect(cros_ish_cl);
> +	ishtp_cl_unlink(cros_ish_cl);
> +	ishtp_cl_flush_queues(cros_ish_cl);
> +
> +	/* Disband and free all Tx and Rx client-level rings */
> +	ishtp_cl_free(cros_ish_cl);
> +}
> +
> +/**
> + * prepare_cros_ec_rx() - Check & prepare receive buffer

Missing @ec_dev

> + * @in_msg:		Incoming message buffer
> + * @cros_ec_command	cros_ec command used to send & receive data

s/cros_ec_command/msg:/

> + *
> + * Check the received buffer. Convert to cros_ec_command format.

Missing description for return value.

> + */
> +static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
> +			      const struct cros_ish_in_msg *in_msg,
> +			      struct cros_ec_command *msg)
> +{
> +	u8 sum = 0;
> +	int i, rv, offset;

nit: Here and in all the code I prefer Reverse X-mas tree when possible, thanks

int i, rv, offset;
u8 sum = 0;

> +
> +	/* Check response error code */
> +	msg->result = in_msg->ec_response.result;
> +	rv = cros_ec_check_result(ec_dev, msg);
> +	if (rv < 0)
> +		return rv;
> +
> +	if (in_msg->ec_response.data_len > msg->insize) {
> +		dev_err(ec_dev->dev, "Packet too long (%d bytes, expected %d)",
> +			in_msg->ec_response.data_len, msg->insize);
> +		return -ENOSPC;
> +	}
> +
> +	/* Copy response packet payload and compute checksum */
> +	for (i = 0; i < sizeof(struct ec_host_response); i++)
> +		sum += ((u8 *)in_msg)[IN_MSG_EC_RESPONSE_PREAMBLE + i];
> +
> +	offset = sizeof(struct cros_ish_in_msg);
> +	for (i = 0; i < in_msg->ec_response.data_len; i++)
> +		sum += msg->data[i] = ((u8 *)in_msg)[offset + i];
> +
> +	if (sum) {
> +		dev_dbg(ec_dev->dev, "Bad received packet checksum %d\n", sum);
> +		return -EBADMSG;
> +	}
> +
> +	return 0;
> +}
> +
> +static int cros_ec_pkt_xfer_ish(struct cros_ec_device *ec_dev,
> +				struct cros_ec_command *msg)
> +{
> +	int rv;
> +	struct ishtp_cl *cros_ish_cl = ec_dev->priv;
> +	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +	struct device *dev = cl_data_to_dev(client_data);
> +	struct cros_ish_in_msg *in_msg = (struct cros_ish_in_msg *)ec_dev->din;
> +	struct cros_ish_out_msg *out_msg =
> +		(struct cros_ish_out_msg *)ec_dev->dout;
> +	size_t in_size = sizeof(struct cros_ish_in_msg) + msg->insize;
> +	size_t out_size = sizeof(struct cros_ish_out_msg) + msg->outsize;
> +
> +	/* Proceed only if reset-init is not in progress */
> +	if (!down_read_trylock(&init_lock)) {
> +		dev_warn(dev,
> +			 "Host is not ready to send messages to ISH. Try again\n");
> +		return -EAGAIN;
> +	}
> +
> +	/* Sanity checks */
> +	if (in_size > ec_dev->din_size) {
> +		dev_err(dev,
> +			"Incoming payload size %zu is too large for ec_dev->din_size %d\n",
> +			in_size, ec_dev->din_size);
> +		return -EMSGSIZE;
> +	}
> +
> +	if (out_size > ec_dev->dout_size) {
> +		dev_err(dev,
> +			"Outgoing payload size %zu is too large for ec_dev->dout_size %d\n",
> +			out_size, ec_dev->dout_size);
> +		return -EMSGSIZE;
> +	}
> +
> +	/* Prepare the package to be sent over ISH TP */
> +	out_msg->hdr.channel = CROS_EC_COMMAND;
> +	out_msg->hdr.status = 0;
> +
> +	ec_dev->dout += OUT_MSG_EC_REQUEST_PREAMBLE;
> +	cros_ec_prepare_tx(ec_dev, msg);
> +	ec_dev->dout -= OUT_MSG_EC_REQUEST_PREAMBLE;
> +
> +	dev_dbg(dev,
> +		"out_msg: struct_ver=0x%x checksum=0x%x command=0x%x command_ver=0x%x data_len=0x%x\n",
> +		out_msg->ec_request.struct_version,
> +		out_msg->ec_request.checksum,
> +		out_msg->ec_request.command,
> +		out_msg->ec_request.command_version,
> +		out_msg->ec_request.data_len);
> +
> +	/* Send command to ISH EC firmware and read response */
> +	rv = ish_send(client_data,
> +		      (u8 *)out_msg, out_size,
> +		      (u8 *)in_msg, in_size);
> +	if (rv < 0)
> +		goto end_error;
> +
> +	rv = prepare_cros_ec_rx(ec_dev, in_msg, msg);
> +	if (rv)
> +		goto end_error;
> +
> +	rv = in_msg->ec_response.data_len;
> +
> +	dev_dbg(dev,
> +		"in_msg: struct_ver=0x%x checksum=0x%x result=0x%x data_len=0x%x\n",
> +		in_msg->ec_response.struct_version,
> +		in_msg->ec_response.checksum,
> +		in_msg->ec_response.result,
> +		in_msg->ec_response.data_len);
> +
> +end_error:
> +	if (msg->command == EC_CMD_REBOOT_EC)
> +		msleep(EC_REBOOT_DELAY_MS);
> +
> +	up_read(&init_lock);
> +
> +	return rv;
> +}
> +
> +static int cros_ec_dev_init(struct ishtp_cl_data *client_data)
> +{
> +	struct cros_ec_device *ec_dev;
> +	struct device *dev = cl_data_to_dev(client_data);
> +
> +	ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
> +	if (!ec_dev)
> +		return -ENOMEM;
> +
> +	client_data->ec_dev = ec_dev;
> +	dev->driver_data = ec_dev;
> +
> +	ec_dev->dev = dev;
> +	ec_dev->priv = client_data->cros_ish_cl;
> +	ec_dev->cmd_xfer = NULL;
> +	ec_dev->pkt_xfer = cros_ec_pkt_xfer_ish;
> +	ec_dev->phys_name = dev_name(dev);
> +	ec_dev->din_size = sizeof(struct cros_ish_in_msg) +
> +			   sizeof(struct ec_response_get_protocol_info);
> +	ec_dev->dout_size = sizeof(struct cros_ish_out_msg);
> +
> +	return cros_ec_register(ec_dev);
> +}
> +
> +static void reset_handler(struct work_struct *work)
> +{
> +	int rv;
> +	struct device *dev;
> +	struct ishtp_cl *cros_ish_cl;
> +	struct ishtp_cl_device *cl_device;
> +	struct ishtp_cl_data *client_data =
> +		container_of(work, struct ishtp_cl_data, work_ishtp_reset);
> +
> +	/* Lock for reset to complete */
> +	down_write(&init_lock);
> +
> +	cros_ish_cl = client_data->cros_ish_cl;
> +	cl_device = client_data->cl_device;
> +
> +	/* Unlink, flush queues & start again */
> +	ishtp_cl_unlink(cros_ish_cl);
> +	ishtp_cl_flush_queues(cros_ish_cl);
> +	ishtp_cl_free(cros_ish_cl);
> +
> +	cros_ish_cl = ishtp_cl_allocate(cl_device);
> +	if (!cros_ish_cl) {
> +		up_write(&init_lock);
> +		return;
> +	}
> +
> +	ishtp_set_drvdata(cl_device, cros_ish_cl);
> +	ishtp_set_client_data(cros_ish_cl, client_data);
> +	client_data->cros_ish_cl = cros_ish_cl;
> +
> +	rv = cros_ish_init(cros_ish_cl);
> +	if (rv) {
> +		ishtp_cl_free(cros_ish_cl);
> +		dev_err(cl_data_to_dev(client_data), "Reset Failed\n");
> +		up_write(&init_lock);
> +		return;
> +	}
> +
> +	/* Refresh ec_dev device pointers */
> +	client_data->ec_dev->priv = client_data->cros_ish_cl;
> +	dev = cl_data_to_dev(client_data);
> +	dev->driver_data = client_data->ec_dev;
> +
> +	dev_info(cl_data_to_dev(client_data), "Chrome EC ISH reset done\n");
> +
> +	up_write(&init_lock);
> +}
> +
> +/**
> + * cros_ec_ishtp_probe() - ISHTP client driver probe callback
> + * @cl_device:		ISHTP client device instance
> + *
> + * Return: 0 for success, negative error code for failure.
> + */
> +static int cros_ec_ishtp_probe(struct ishtp_cl_device *cl_device)
> +{
> +	int rv;
> +	struct ishtp_cl *cros_ish_cl;
> +	struct ishtp_cl_data *client_data =
> +		devm_kzalloc(ishtp_device(cl_device),
> +			     sizeof(*client_data), GFP_KERNEL);
> +	if (!client_data)
> +		return -ENOMEM;
> +
> +	/* Lock for initialization to complete */
> +	down_write(&init_lock);
> +
> +	cros_ish_cl = ishtp_cl_allocate(cl_device);
> +	if (!cros_ish_cl) {
> +		rv = -ENOMEM;
> +		goto end_ishtp_cl_alloc_error;
> +	}
> +
> +	ishtp_set_drvdata(cl_device, cros_ish_cl);
> +	ishtp_set_client_data(cros_ish_cl, client_data);
> +	client_data->cros_ish_cl = cros_ish_cl;
> +	client_data->cl_device = cl_device;
> +
> +	init_waitqueue_head(&client_data->response.wait_queue);
> +
> +	INIT_WORK(&client_data->work_ishtp_reset,
> +		  reset_handler);
> +	INIT_WORK(&client_data->work_ec_evt,
> +		  ish_evt_handler);
> +
> +	rv = cros_ish_init(cros_ish_cl);
> +	if (rv)
> +		goto end_ishtp_cl_init_error;
> +
> +	ishtp_get_device(cl_device);
> +
> +	up_write(&init_lock);
> +
> +	/* Register croc_ec_dev mfd */
> +	rv = cros_ec_dev_init(client_data);
> +	if (rv)
> +		goto end_cros_ec_dev_init_error;
> +
> +	return 0;
> +
> +end_cros_ec_dev_init_error:
> +	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
> +	ishtp_cl_disconnect(cros_ish_cl);
> +	ishtp_cl_unlink(cros_ish_cl);
> +	ishtp_cl_flush_queues(cros_ish_cl);
> +	ishtp_put_device(cl_device);
> +end_ishtp_cl_init_error:
> +	ishtp_cl_free(cros_ish_cl);
> +end_ishtp_cl_alloc_error:
> +	up_write(&init_lock);
> +	return rv;
> +}
> +
> +/**
> + * cros_ec_ishtp_remove() - ISHTP client driver remove callback
> + * @cl_device:		ISHTP client device instance
> + *
> + * Return: 0
> + */
> +static int cros_ec_ishtp_remove(struct ishtp_cl_device *cl_device)
> +{
> +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> +	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +	cancel_work_sync(&client_data->work_ishtp_reset);
> +	cancel_work_sync(&client_data->work_ec_evt);
> +	cros_ish_deinit(cros_ish_cl);
> +	ishtp_put_device(cl_device);
> +
> +	return 0;
> +}
> +
> +/**
> + * cros_ec_ishtp_reset() - ISHTP client driver reset callback
> + * @cl_device:		ISHTP client device instance
> + *
> + * Return: 0
> + */
> +static int cros_ec_ishtp_reset(struct ishtp_cl_device *cl_device)
> +{
> +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> +	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +	schedule_work(&client_data->work_ishtp_reset);
> +
> +	return 0;
> +}
> +
> +/**
> + * cros_ec_ishtp_suspend() - ISHTP client driver suspend callback
> + * @device:	device instance
> + *
> + * Return: 0 for success, negative error code for failure.
> + */
> +static int __maybe_unused cros_ec_ishtp_suspend(struct device *device)
> +{
> +	struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> +	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +	return cros_ec_suspend(client_data->ec_dev);
> +}
> +
> +/**
> + * cros_ec_ishtp_resume() - ISHTP client driver resume callback
> + * @device:	device instance
> + *
> + * Return: 0 for success, negative error code for failure.
> + */
> +static int __maybe_unused cros_ec_ishtp_resume(struct device *device)
> +{
> +	struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> +	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +	return cros_ec_resume(client_data->ec_dev);
> +}
> +
> +static SIMPLE_DEV_PM_OPS(cros_ec_ishtp_pm_ops, cros_ec_ishtp_suspend,
> +			 cros_ec_ishtp_resume);
> +
> +static struct ishtp_cl_driver	cros_ec_ishtp_driver = {
> +	.name = "cros_ec_ishtp",
> +	.guid = &cros_ish_guid,
> +	.probe = cros_ec_ishtp_probe,
> +	.remove = cros_ec_ishtp_remove,
> +	.reset = cros_ec_ishtp_reset,
> +	.driver = {
> +		.pm = &cros_ec_ishtp_pm_ops,
> +	},
> +};
> +
> +static int __init cros_ec_ishtp_mod_init(void)
> +{
> +	return ishtp_cl_driver_register(&cros_ec_ishtp_driver, THIS_MODULE);
> +}
> +
> +static void __exit cros_ec_ishtp_mod_exit(void)
> +{
> +	ishtp_cl_driver_unregister(&cros_ec_ishtp_driver);
> +}
> +
> +module_init(cros_ec_ishtp_mod_init);
> +module_exit(cros_ec_ishtp_mod_exit);
> +
> +MODULE_DESCRIPTION("ChromeOS EC ISHTP Client Driver");
> +MODULE_AUTHOR("Rushikesh S Kadam <rushikesh.s.kadam@intel.com>");
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("ishtp:*");
> 

Remember to run:

scripts/kernel-doc -v -none drivers/platform/chrome/cros_ec_ishtp.c

and

scripts/checkpatch.pl --strict -f drivers/platform/chrome/cros_ec_ishtp.c

before send the patch.

Thanks,
 Enric