RE: [RESEND PATCH v2 1/1] ishtp: Add support for Intel ishtp eclite driver

["K Naduvalath, Sumesh" <sumesh.k.naduvalath@intel.com>]

Thank you Hans for your review comments, and my apologies for the delayed response.
Please find my reply inline -

> -----Original Message-----
> From: Hans de Goede <hdegoede@redhat.com>
> Sent: Monday, August 9, 2021 2:24 PM
> To: K Naduvalath, Sumesh <sumesh.k.naduvalath@intel.com>;
> mgross@linux.intel.com; srinivas.pandruvada@linux.intel.com
> Cc: Pandruvada, Srinivas <srinivas.pandruvada@intel.com>; platform-driver-
> x86@vger.kernel.org; linux-kernel@vger.kernel.org; Chinnu, Ganapathi
> <ganapathi.chinnu@intel.com>; Kumar, Nachiketa
> <nachiketa.kumar@intel.com>
> Subject: Re: [RESEND PATCH v2 1/1] ishtp: Add support for Intel ishtp eclite
> driver
> 
> Hi,
> 
> Thank you for the new version. This mostly looks good, some small remarks
> below / inline :
> 
> On 7/30/21 5:58 PM, sumesh.k.naduvalath@intel.com wrote:
> > From: "K Naduvalath, Sumesh" <sumesh.k.naduvalath@intel.com>
> >
> > This driver is for accessing the PSE (Programmable Service Engine), an
> > Embedded Controller like IP, using ISHTP (Integratd Sensor Hub
> > Transport
> > Protocol) to get battery, thermal and UCSI (USB Type-C Connector
> > System Software Interface) related data from the platform.
> >
> > Signed-off-by: K Naduvalath, Sumesh <sumesh.k.naduvalath@intel.com>
> > Reviewed-by: Mark Gross <mgross@linux.intel.com>
> > ---
> > Changes:
> >
> > v2:
> > -Decoupled ACPI device search with acpi_find_device() and cache adev
> > -Opregion context is protected with lock for both cmd and data
> > handlers -Opregion length check added in various functions
> > -ishtp_get_device and ishtp_put_device are removed
> > -acpi_walk_dep_device_list() changed to acpi_dev_clear_dependencies()
> > -Kconfig text, cosmetic and minor corrections
> >
> > v1:
> > -Initial Version
> >
> >  MAINTAINERS                               |   6 +
> >  drivers/platform/x86/Kconfig              |  16 +
> >  drivers/platform/x86/Makefile             |   1 +
> >  drivers/platform/x86/intel_ishtp_eclite.c | 699
> > ++++++++++++++++++++++
> >  4 files changed, 722 insertions(+)
> >  create mode 100644 drivers/platform/x86/intel_ishtp_eclite.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS index
> > a61f4f3b78a9..bb2b5be3c745 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -9391,6 +9391,12 @@ L:	linux-crypto@vger.kernel.org
> >  S:	Maintained
> >  F:	drivers/crypto/ixp4xx_crypto.c
> >
> > +INTEL ISHTP ECLITE DRIVER
> > +M:	Sumesh K Naduvalath <sumesh.k.naduvalath@intel.com>
> > +L:	platform-driver-x86@vger.kernel.org
> > +S:	Supported
> > +F:	drivers/platform/x86/intel_ishtp_eclite.c
> > +
> >  INTEL IXP4XX QMGR, NPE, ETHERNET and HSS SUPPORT
> >  M:	Krzysztof Halasa <khalasa@piap.pl>
> >  S:	Maintained
> > diff --git a/drivers/platform/x86/Kconfig
> > b/drivers/platform/x86/Kconfig index 7d385c3b2239..ee5fe5e52033
> 100644
> > --- a/drivers/platform/x86/Kconfig
> > +++ b/drivers/platform/x86/Kconfig
> > @@ -1173,6 +1173,22 @@ config INTEL_CHTDC_TI_PWRBTN
> >  	  To compile this driver as a module, choose M here: the module
> >  	  will be called intel_chtdc_ti_pwrbtn.
> >
> > +config INTEL_ISHTP_ECLITE
> > +	tristate "Intel ISHTP eclite controller"
> > +	depends on INTEL_ISH_HID
> > +	depends on ACPI
> > +	help
> > +	  This driver is for accessing the PSE (Programmable Service Engine),
> > +	  an Embedded Controller like IP, using ISHTP (Integrated Sensor Hub
> > +	  Transport Protocol) to get battery, thermal and UCSI (USB Type-C
> > +          Connector System Software Interface) related data from the
> platform.
> > +	  Users who don't want to use discrete Embedded Controller on
> Intel's
> > +	  Elkhartlake platform, can leverage this integrated solution of
> > +	  ECLite which is part of PSE subsystem.
> > +
> > +	  To compile this driver as a module, choose M here: the module
> > +	  will be called intel_ishtp_eclite
> > +
> >  config INTEL_MRFLD_PWRBTN
> >  	tristate "Intel Merrifield Basin Cove power button driver"
> >  	depends on INTEL_SOC_PMIC_MRFLD
> > diff --git a/drivers/platform/x86/Makefile
> > b/drivers/platform/x86/Makefile index 7ee369aab10d..568c9c7d4173
> > 100644
> > --- a/drivers/platform/x86/Makefile
> > +++ b/drivers/platform/x86/Makefile
> > @@ -75,6 +75,7 @@ obj-$(CONFIG_INTEL_INT0002_VGPIO)	+=
> intel_int0002_vgpio.o
> >  obj-$(CONFIG_INTEL_MENLOW)		+= intel_menlow.o
> >  obj-$(CONFIG_INTEL_OAKTRAIL)		+= intel_oaktrail.o
> >  obj-$(CONFIG_INTEL_VBTN)		+= intel-vbtn.o
> > +obj-$(CONFIG_INTEL_ISHTP_ECLITE)	+= intel_ishtp_eclite.o
> >
> >  # MSI
> >  obj-$(CONFIG_MSI_LAPTOP)	+= msi-laptop.o
> > diff --git a/drivers/platform/x86/intel_ishtp_eclite.c
> > b/drivers/platform/x86/intel_ishtp_eclite.c
> > new file mode 100644
> > index 000000000000..d5611b1a13df
> > --- /dev/null
> > +++ b/drivers/platform/x86/intel_ishtp_eclite.c
> > @@ -0,0 +1,699 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Intel ECLite opregion driver for talking to ECLite firmware
> > +running on
> > + * Intel Integrated Sensor Hub (ISH) using ISH Transport Protocol
> > +(ISHTP)
> > + *
> > + * Copyright (c) 2021, Intel Corporation.
> > + */
> > +
> > +#include <linux/acpi.h>
> > +#include <linux/bitops.h>
> > +#include <linux/device.h>
> > +#include <linux/errno.h>
> > +#include <linux/intel-ish-client-if.h> #include <linux/kernel.h>
> > +#include <linux/module.h> #include <linux/mutex.h> #include
> > +<linux/slab.h> #include <linux/suspend.h> #include <linux/types.h>
> > +#include <linux/uuid.h> #include <linux/uaccess.h>
> > +
> > +#define ECLITE_DATA_OPREGION_ID	0x9E
> > +#define ECLITE_CMD_OPREGION_ID	0x9F
> > +
> > +#define ECL_MSG_DATA	0x1
> > +#define ECL_MSG_EVENT	0x2
> > +
> > +#define ECL_ISH_READ	0x1
> > +#define ECL_ISH_WRITE	0x2
> > +#define ECL_ISH_HEADER_VERSION	0
> > +
> > +#define ECL_CL_RX_RING_SIZE	16
> > +#define ECL_CL_TX_RING_SIZE	8
> > +
> > +#define ECL_DATA_OPR_BUFLEN	384
> > +#define ECL_EVENTS_NOTIFY	333
> > +
> > +#define cmd_opr_offsetof(element)	offsetof(struct opregion_cmd,
> element)
> > +#define cl_data_to_dev(opr_dev)	ishtp_device((opr_dev)->cl_device)
> > +
> > +#ifndef BITS_TO_BYTES
> > +#define BITS_TO_BYTES(x) ((x) / 8)
> > +#endif
> > +
> > +struct opregion_cmd {
> > +	unsigned int command;
> > +	unsigned int offset;
> > +	unsigned int length;
> > +	unsigned int event_id;
> > +};
> > +
> > +struct opregion_data {
> > +	char data[ECL_DATA_OPR_BUFLEN];
> > +};
> > +
> > +struct opregion_context {
> > +	struct opregion_cmd cmd_area;
> > +	struct opregion_data data_area;
> > +};
> > +
> > +struct ecl_message_header {
> > +	unsigned int version:2;
> > +	unsigned int data_type:2;
> > +	unsigned int request_type:2;
> > +	unsigned int offset:9;
> > +	unsigned int data_len:9;
> > +	unsigned int event:8;
> > +};
> > +
> > +struct ecl_message {
> > +	struct ecl_message_header header;
> > +	char payload[ECL_DATA_OPR_BUFLEN];
> > +};
> > +
> > +struct ishtp_opregion_dev {
> > +	struct opregion_context opr_context;
> > +	struct ishtp_cl *ecl_ishtp_cl;
> > +	struct ishtp_cl_device *cl_device;
> > +	struct ishtp_fw_client *fw_client;
> > +	struct ishtp_cl_rb *rb;
> > +	struct acpi_device *adev;
> > +	unsigned int dsm_event_id;
> > +	unsigned int ish_link_ready;
> > +	unsigned int ish_read_done;
> > +	unsigned int acpi_init_done;
> > +	wait_queue_head_t read_wait;
> > +	struct work_struct event_work;
> > +	struct work_struct reset_work;
> > +	/* lock for opregion context */
> > +	struct mutex lock;
> > +
> > +};
> > +
> > +/* eclite ishtp client UUID: 6a19cc4b-d760-4de3-b14d-f25ebd0fbcd9 */
> > +static const guid_t ecl_ishtp_guid =
> > +	GUID_INIT(0x6a19cc4b, 0xd760, 0x4de3,
> > +		  0xb1, 0x4d, 0xf2, 0x5e, 0xbd, 0xf, 0xbc, 0xd9);
> > +
> > +/* ACPI DSM UUID: 91d936a7-1f01-49c6-a6b4-72f00ad8d8a5 */ static
> > +const guid_t ecl_acpi_guid =
> > +	GUID_INIT(0x91d936a7, 0x1f01, 0x49c6, 0xa6,
> > +		  0xb4, 0x72, 0xf0, 0x0a, 0xd8, 0xd8, 0xa5);
> > +
> > +/**
> > + * ecl_ish_cl_read() - Read data from eclite FW
> > + *
> > + * @opr_dev:  pointer to opregion device
> > + *
> > + * This function issues a read request to eclite FW and waits until
> > +it
> > + * receives a response. When response is received the read data is
> > +copied to
> > + * opregion buffer.
> > + */
> > +static int ecl_ish_cl_read(struct ishtp_opregion_dev *opr_dev) {
> > +	struct ecl_message_header header;
> > +	int len, rv;
> > +
> > +	if (!opr_dev->ish_link_ready)
> > +		return -EIO;
> > +
> > +	if ((opr_dev->opr_context.cmd_area.offset +
> > +	     opr_dev->opr_context.cmd_area.length) >
> ECL_DATA_OPR_BUFLEN) {
> > +		return -EINVAL;
> > +	}
> > +
> > +	header.version = ECL_ISH_HEADER_VERSION;
> > +	header.data_type = ECL_MSG_DATA;
> > +	header.request_type = ECL_ISH_READ;
> > +	header.offset = opr_dev->opr_context.cmd_area.offset;
> > +	header.data_len = opr_dev->opr_context.cmd_area.length;
> > +	header.event = opr_dev->opr_context.cmd_area.event_id;
> > +	len = sizeof(header);
> > +
> > +	opr_dev->ish_read_done = false;
> > +	rv = ishtp_cl_send(opr_dev->ecl_ishtp_cl, (uint8_t *)&header, len);
> > +	if (rv) {
> > +		dev_err(cl_data_to_dev(opr_dev), "ish-read : send
> failed\n");
> > +		return -EIO;
> > +	}
> > +
> > +	dev_dbg(cl_data_to_dev(opr_dev),
> > +		"[ish_rd] Req: off : %x, len : %x\n",
> > +		header.offset,
> > +		header.data_len);
> > +
> > +	rv = wait_event_interruptible_timeout(opr_dev->read_wait,
> > +					      opr_dev->ish_read_done,
> > +					      2 * HZ);
> > +	if (!rv) {
> > +		dev_err(cl_data_to_dev(opr_dev),
> > +			"[ish_rd] No response from firmware\n");
> > +		return -EIO;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +/**
> > + * ecl_ish_cl_write() - This function writes data to eclite FW.
> > + *
> > + * @opr_dev:  pointer to opregion device
> > + *
> > + * This function writes data to eclite FW.
> > + */
> > +static int ecl_ish_cl_write(struct ishtp_opregion_dev *opr_dev) {
> > +	struct ecl_message message;
> > +	int len;
> > +
> > +	if (!opr_dev->ish_link_ready)
> > +		return -EIO;
> > +
> > +	if ((opr_dev->opr_context.cmd_area.offset +
> > +	     opr_dev->opr_context.cmd_area.length) >
> ECL_DATA_OPR_BUFLEN) {
> > +		return -EINVAL;
> > +	}
> > +
> > +	message.header.version = ECL_ISH_HEADER_VERSION;
> > +	message.header.data_type = ECL_MSG_DATA;
> > +	message.header.request_type = ECL_ISH_WRITE;
> > +	message.header.offset = opr_dev->opr_context.cmd_area.offset;
> > +	message.header.data_len = opr_dev->opr_context.cmd_area.length;
> > +	message.header.event = opr_dev->opr_context.cmd_area.event_id;
> > +	len = sizeof(struct ecl_message_header) + message.header.data_len;
> > +
> > +	memcpy(message.payload,
> > +	       opr_dev->opr_context.data_area.data + message.header.offset,
> > +	       message.header.data_len);
> > +
> > +	dev_dbg(cl_data_to_dev(opr_dev),
> > +		"[ish_wr] off : %x, len : %x\n",
> > +		message.header.offset,
> > +		message.header.data_len);
> > +
> > +	return ishtp_cl_send(opr_dev->ecl_ishtp_cl, (uint8_t *)&message,
> > +len); }
> > +
> > +static acpi_status
> > +ecl_opregion_cmd_handler(u32 function, acpi_physical_address address,
> > +			 u32 bits, u64 *value64,
> > +			 void *handler_context, void *region_context) {
> > +	struct ishtp_opregion_dev *opr_dev;
> > +	struct opregion_cmd *cmd;
> > +	acpi_status status = AE_OK;
> > +
> > +	if (!region_context || !value64)
> > +		return AE_BAD_PARAMETER;
> > +
> > +	if (function == ACPI_READ)
> > +		return AE_ERROR;
> > +
> > +	opr_dev = (struct ishtp_opregion_dev *)region_context;
> > +
> > +	mutex_lock(&opr_dev->lock);
> > +
> > +	cmd = &opr_dev->opr_context.cmd_area;
> > +
> > +	switch (address) {
> > +	case cmd_opr_offsetof(command):
> > +		cmd->command = (u32)*value64;
> > +
> > +		if (cmd->command == ECL_ISH_READ)
> > +			status =  ecl_ish_cl_read(opr_dev);
> > +		else if (cmd->command == ECL_ISH_WRITE)
> > +			status = ecl_ish_cl_write(opr_dev);
> > +		else
> > +			status = AE_ERROR;
> > +		break;
> > +	case cmd_opr_offsetof(offset):
> > +		cmd->offset = (u32)*value64;
> > +		break;
> > +	case cmd_opr_offsetof(length):
> > +		cmd->length = (u32)*value64;
> > +		break;
> > +	case cmd_opr_offsetof(event_id):
> > +		cmd->event_id = (u32)*value64;
> > +		break;
> > +	default:
> > +		status = AE_ERROR;
> > +	}
> > +
> > +	mutex_unlock(&opr_dev->lock);
> > +
> > +	return status;
> > +}
> > +
> > +static acpi_status
> > +ecl_opregion_data_handler(u32 function, acpi_physical_address address,
> > +			  u32 bits, u64 *value64,
> > +			  void *handler_context, void *region_context) {
> > +	struct ishtp_opregion_dev *opr_dev;
> > +	unsigned int bytes = BITS_TO_BYTES(bits);
> > +	void *data_addr;
> > +
> > +	if (!region_context || !value64)
> > +		return AE_BAD_PARAMETER;
> > +
> > +	if (address + bytes > ECL_DATA_OPR_BUFLEN)
> > +		return AE_BAD_PARAMETER;
> > +
> > +	opr_dev = (struct ishtp_opregion_dev *)region_context;
> > +
> > +	mutex_lock(&opr_dev->lock);
> > +
> > +	data_addr = &opr_dev->opr_context.data_area.data[address];
> > +
> > +	if (function == ACPI_READ) {
> > +		memcpy(value64, data_addr, bytes);
> > +	} else if (function == ACPI_WRITE) {
> > +		memcpy(data_addr, value64, bytes);
> > +	} else {
> > +		mutex_unlock(&opr_dev->lock);
> > +		return AE_BAD_PARAMETER;
> > +	}
> > +
> > +	mutex_unlock(&opr_dev->lock);
> > +
> > +	return AE_OK;
> > +}
> > +
> > +static int acpi_find_eclite_device(struct ishtp_opregion_dev
> > +*opr_dev) {
> > +	struct acpi_device *adev;
> > +
> > +	/* Find ECLite device and install opregion handlers */
> > +	adev = acpi_dev_get_first_match_dev("INTC1035", NULL, -1);
> > +	if (!adev) {
> > +		dev_err(cl_data_to_dev(opr_dev), "eclite ACPI device not
> found\n");
> > +		return -ENODEV;
> > +	}
> > +
> > +	opr_dev->adev = adev;
> > +	acpi_dev_put(adev);
> 
> Please move this put() to the end of ecl_ishtp_cl_remove(), so that our
> reference stays valid until the driver is unbound.

Sure, I'll move them to ecl_ishtp_cl_remove()

> 
> > +
> > +	return 0;
> > +}
> > +
> > +static int acpi_opregion_init(struct ishtp_opregion_dev *opr_dev) {
> > +	acpi_status status;
> > +
> > +	status = acpi_install_address_space_handler(opr_dev->adev-
> >handle,
> > +
> ECLITE_CMD_OPREGION_ID,
> > +
> ecl_opregion_cmd_handler,
> > +						    NULL, opr_dev);
> > +	if (ACPI_FAILURE(status)) {
> > +		dev_err(cl_data_to_dev(opr_dev),
> > +			"cmd space handler install failed\n");
> > +		return -ENODEV;
> > +	}
> > +
> > +	status = acpi_install_address_space_handler(opr_dev->adev-
> >handle,
> > +
> ECLITE_DATA_OPREGION_ID,
> > +
> ecl_opregion_data_handler,
> > +						    NULL, opr_dev);
> > +	if (ACPI_FAILURE(status)) {
> > +		dev_err(cl_data_to_dev(opr_dev),
> > +			"data space handler install failed\n");
> > +
> > +		acpi_remove_address_space_handler(opr_dev->adev-
> >handle,
> > +						  ECLITE_CMD_OPREGION_ID,
> > +						  ecl_opregion_cmd_handler);
> > +		return -ENODEV;
> > +	}
> > +	opr_dev->acpi_init_done = true;
> > +
> > +	dev_dbg(cl_data_to_dev(opr_dev), "Opregion handlers are
> > +installed\n");
> > +
> > +	return 0;
> > +}
> > +
> > +static void acpi_opregion_deinit(struct ishtp_opregion_dev *opr_dev)
> > +{
> > +	acpi_remove_address_space_handler(opr_dev->adev->handle,
> > +					  ECLITE_CMD_OPREGION_ID,
> > +					  ecl_opregion_cmd_handler);
> > +
> > +	acpi_remove_address_space_handler(opr_dev->adev->handle,
> > +					  ECLITE_DATA_OPREGION_ID,
> > +					  ecl_opregion_data_handler);
> > +	opr_dev->acpi_init_done = false;
> > +}
> > +
> > +static void ecl_acpi_invoke_dsm(struct work_struct *work) {
> > +	struct ishtp_opregion_dev *opr_dev;
> > +	union acpi_object *obj;
> > +
> > +	opr_dev = container_of(work, struct ishtp_opregion_dev,
> event_work);
> > +	if (!opr_dev->acpi_init_done)
> > +		return;
> > +
> > +	obj = acpi_evaluate_dsm(opr_dev->adev->handle, &ecl_acpi_guid, 0,
> > +				opr_dev->dsm_event_id, NULL);
> > +	if (!obj) {
> > +		dev_warn(cl_data_to_dev(opr_dev), "_DSM fn call failed\n");
> > +		return;
> > +	}
> > +
> > +	dev_dbg(cl_data_to_dev(opr_dev), "Exec DSM function code: %d
> success\n",
> > +		opr_dev->dsm_event_id);
> > +
> > +	ACPI_FREE(obj);
> > +}
> > +
> > +static void ecl_ish_process_rx_data(struct ishtp_opregion_dev
> > +*opr_dev) {
> > +	struct ecl_message *message =
> > +		(struct ecl_message *)opr_dev->rb->buffer.data;
> > +
> > +	dev_dbg(cl_data_to_dev(opr_dev),
> > +		"[ish_rd] Resp: off : %x, len : %x\n",
> > +		message->header.offset,
> > +		message->header.data_len);
> > +
> > +	if ((message->header.offset + message->header.data_len) >
> > +			ECL_DATA_OPR_BUFLEN) {
> > +		return;
> > +	}
> > +
> > +	memcpy(opr_dev->opr_context.data_area.data + message-
> >header.offset,
> > +	       message->payload, message->header.data_len);
> > +
> > +	opr_dev->ish_read_done = true;
> > +	wake_up_interruptible(&opr_dev->read_wait);
> > +}
> > +
> > +static void ecl_ish_process_rx_event(struct ishtp_opregion_dev
> > +*opr_dev) {
> > +	struct ecl_message_header *header =
> > +		(struct ecl_message_header *)opr_dev->rb->buffer.data;
> > +
> > +	dev_dbg(cl_data_to_dev(opr_dev),
> > +		"[ish_ev] Evt received: %8x\n", header->event);
> > +
> > +	opr_dev->dsm_event_id = header->event;
> > +	schedule_work(&opr_dev->event_work);
> > +}
> > +
> > +static int ecl_ish_cl_enable_events(struct ishtp_opregion_dev *opr_dev,
> > +				    bool config_enable)
> > +{
> > +	struct ecl_message message;
> > +	int len;
> > +
> > +	message.header.version = ECL_ISH_HEADER_VERSION;
> > +	message.header.data_type = ECL_MSG_DATA;
> > +	message.header.request_type = ECL_ISH_WRITE;
> > +	message.header.offset = ECL_EVENTS_NOTIFY;
> > +	message.header.data_len = 1;
> > +	message.payload[0] = config_enable;
> > +
> > +	len = sizeof(struct ecl_message_header) + message.header.data_len;
> > +
> > +	return ishtp_cl_send(opr_dev->ecl_ishtp_cl, (uint8_t *)&message,
> > +len); }
> > +
> > +static void ecl_ishtp_cl_event_cb(struct ishtp_cl_device *cl_device)
> > +{
> > +	struct ishtp_cl *ecl_ishtp_cl = ishtp_get_drvdata(cl_device);
> > +	struct ishtp_opregion_dev *opr_dev;
> > +	struct ecl_message_header *header;
> > +	struct ishtp_cl_rb *rb;
> > +
> > +	opr_dev = ishtp_get_client_data(ecl_ishtp_cl);
> > +	while ((rb = ishtp_cl_rx_get_rb(opr_dev->ecl_ishtp_cl)) != NULL) {
> > +		opr_dev->rb = rb;
> > +		header = (struct ecl_message_header *)rb->buffer.data;
> > +
> > +		if (header->data_type == ECL_MSG_DATA)
> > +			ecl_ish_process_rx_data(opr_dev);
> > +		else if (header->data_type == ECL_MSG_EVENT)
> > +			ecl_ish_process_rx_event(opr_dev);
> > +		else
> > +			/* Got an event with wrong data_type, ignore it */
> > +			dev_err(cl_data_to_dev(opr_dev),
> > +				"[ish_cb] Received wrong data_type\n");
> > +
> > +		ishtp_cl_io_rb_recycle(rb);
> > +	}
> > +}
> > +
> > +static int ecl_ishtp_cl_init(struct ishtp_cl *ecl_ishtp_cl) {
> > +	struct ishtp_opregion_dev *opr_dev =
> > +		ishtp_get_client_data(ecl_ishtp_cl);
> > +	struct ishtp_fw_client *fw_client;
> > +	struct ishtp_device *dev;
> > +	int rv;
> > +
> > +	rv = ishtp_cl_link(ecl_ishtp_cl);
> > +	if (rv) {
> > +		dev_err(cl_data_to_dev(opr_dev), "ishtp_cl_link failed\n");
> > +		return	rv;
> > +	}
> > +
> > +	dev = ishtp_get_ishtp_device(ecl_ishtp_cl);
> > +
> > +	/* Connect to FW client */
> > +	ishtp_set_tx_ring_size(ecl_ishtp_cl, ECL_CL_TX_RING_SIZE);
> > +	ishtp_set_rx_ring_size(ecl_ishtp_cl, ECL_CL_RX_RING_SIZE);
> > +
> > +	fw_client = ishtp_fw_cl_get_client(dev, &ecl_ishtp_guid);
> > +	if (!fw_client) {
> > +		dev_err(cl_data_to_dev(opr_dev), "fw client not found\n");
> > +		return -ENOENT;
> > +	}
> > +
> > +	ishtp_cl_set_fw_client_id(ecl_ishtp_cl,
> > +				  ishtp_get_fw_client_id(fw_client));
> > +
> > +	ishtp_set_connection_state(ecl_ishtp_cl, ISHTP_CL_CONNECTING);
> > +
> > +	rv = ishtp_cl_connect(ecl_ishtp_cl);
> > +	if (rv) {
> > +		dev_err(cl_data_to_dev(opr_dev), "client connect failed\n");
> > +
> > +		ishtp_cl_unlink(ecl_ishtp_cl);
> > +		return rv;
> > +	}
> > +
> > +	dev_dbg(cl_data_to_dev(opr_dev), "Host connected to fw client\n");
> > +
> > +	return 0;
> > +}
> > +
> > +static void ecl_ishtp_cl_deinit(struct ishtp_cl *ecl_ishtp_cl) {
> > +	ishtp_cl_unlink(ecl_ishtp_cl);
> > +	ishtp_cl_flush_queues(ecl_ishtp_cl);
> > +	ishtp_cl_free(ecl_ishtp_cl);
> > +}
> > +
> > +static void ecl_ishtp_cl_reset_handler(struct work_struct *work) {
> > +	struct ishtp_opregion_dev *opr_dev;
> > +	struct ishtp_cl_device *cl_device;
> > +	struct ishtp_cl *ecl_ishtp_cl;
> > +	int rv;
> > +	int retry;
> > +
> > +	opr_dev = container_of(work, struct ishtp_opregion_dev,
> reset_work);
> > +
> > +	opr_dev->ish_link_ready = false;
> > +
> > +	cl_device = opr_dev->cl_device;
> > +	ecl_ishtp_cl = opr_dev->ecl_ishtp_cl;
> > +
> > +	ecl_ishtp_cl_deinit(ecl_ishtp_cl);
> > +
> > +	ecl_ishtp_cl = ishtp_cl_allocate(cl_device);
> > +	if (!ecl_ishtp_cl)
> > +		return;
> > +
> > +	ishtp_set_drvdata(cl_device, ecl_ishtp_cl);
> > +	ishtp_set_client_data(ecl_ishtp_cl, opr_dev);
> > +
> > +	opr_dev->ecl_ishtp_cl = ecl_ishtp_cl;
> > +
> > +	for (retry = 0; retry < 3; ++retry) {
> > +		rv = ecl_ishtp_cl_init(ecl_ishtp_cl);
> > +		if (!rv)
> > +			break;
> > +	}
> > +	if (rv) {
> > +		ishtp_cl_free(ecl_ishtp_cl);
> > +		opr_dev->ecl_ishtp_cl = NULL;
> > +		dev_err(cl_data_to_dev(opr_dev),
> > +			"[ish_rst] Reset failed. Link not ready.\n");
> > +		return;
> > +	}
> > +
> > +	ishtp_register_event_cb(cl_device, ecl_ishtp_cl_event_cb);
> > +	dev_info(cl_data_to_dev(opr_dev),
> > +		 "[ish_rst] Reset Success. Link ready.\n");
> > +
> > +	opr_dev->ish_link_ready = true;
> > +
> > +	if (opr_dev->acpi_init_done)
> > +		return;
> > +
> > +	rv = acpi_opregion_init(opr_dev);
> > +	if (rv) {
> > +		dev_err(cl_data_to_dev(opr_dev),
> > +			"ACPI opregion init failed\n");
> > +	}
> > +}
> > +
> > +static int ecl_ishtp_cl_probe(struct ishtp_cl_device *cl_device) {
> > +	struct ishtp_cl *ecl_ishtp_cl;
> > +	struct ishtp_opregion_dev *opr_dev;
> > +	int rv;
> > +
> > +	opr_dev = devm_kzalloc(ishtp_device(cl_device), sizeof(*opr_dev),
> > +			       GFP_KERNEL);
> > +	if (!opr_dev)
> > +		return -ENOMEM;
> > +
> > +	ecl_ishtp_cl = ishtp_cl_allocate(cl_device);
> > +	if (!ecl_ishtp_cl)
> > +		return -ENOMEM;
> > +
> > +	ishtp_set_drvdata(cl_device, ecl_ishtp_cl);
> > +	ishtp_set_client_data(ecl_ishtp_cl, opr_dev);
> > +	opr_dev->ecl_ishtp_cl = ecl_ishtp_cl;
> > +	opr_dev->cl_device = cl_device;
> > +
> > +	init_waitqueue_head(&opr_dev->read_wait);
> > +	INIT_WORK(&opr_dev->event_work, ecl_acpi_invoke_dsm);
> > +	INIT_WORK(&opr_dev->reset_work, ecl_ishtp_cl_reset_handler);
> > +
> > +	/* Initialize ish client device */
> > +	rv = ecl_ishtp_cl_init(ecl_ishtp_cl);
> > +	if (rv) {
> > +		dev_err(cl_data_to_dev(opr_dev), "Client init failed\n");
> > +		goto err_exit;
> > +	}
> > +
> > +	dev_dbg(cl_data_to_dev(opr_dev), "eclite-ishtp client
> > +initialised\n");
> > +
> > +	/* Register a handler for eclite fw events */
> > +	ishtp_register_event_cb(cl_device, ecl_ishtp_cl_event_cb);
> 
> ecl_ishtp_cl_event_cb may queue event_work which uses the adev pointer,
> so this needs to be moved to after the acpi_find_eclite_device() call.
> 

I'll move them to the end of probe(), it makes sense.

> > +
> > +	opr_dev->ish_link_ready = true;
> > +	mutex_init(&opr_dev->lock);
> > +
> > +	/* Now find ACPI device and init opregion handlers */
> > +	rv = acpi_find_eclite_device(opr_dev);
> > +	if (rv) {
> > +		dev_err(cl_data_to_dev(opr_dev), "ECLite ACPI ID not
> found\n");
> > +		goto err_exit;
> > +	}
> > +	rv = acpi_opregion_init(opr_dev);
> > +	if (rv) {
> > +		dev_err(cl_data_to_dev(opr_dev), "ACPI opregion init
> failed\n");
> > +		goto err_exit;
> > +	}
> > +
> > +	/* Reprobe devices depending on ECLite - battery, fan, etc. */
> > +	acpi_dev_clear_dependencies(opr_dev->adev);
> > +
> > +	return 0;
> > +err_exit:
> > +	ishtp_set_connection_state(ecl_ishtp_cl,
> ISHTP_CL_DISCONNECTING);
> > +	ishtp_cl_disconnect(ecl_ishtp_cl);
> > +	ecl_ishtp_cl_deinit(ecl_ishtp_cl);
> > +
> > +	return rv;
> > +}
> > +
> > +static void ecl_ishtp_cl_remove(struct ishtp_cl_device *cl_device) {
> > +	struct ishtp_cl *ecl_ishtp_cl = ishtp_get_drvdata(cl_device);
> > +	struct ishtp_opregion_dev *opr_dev =
> > +		ishtp_get_client_data(ecl_ishtp_cl);
> > +
> > +	if (opr_dev->acpi_init_done)
> > +		acpi_opregion_deinit(opr_dev);
> > +
> > +	cancel_work_sync(&opr_dev->reset_work);
> > +	cancel_work_sync(&opr_dev->event_work);
> 
> Does the ISH bus guarantee that ecl_ishtp_cl_event_cb and
> ecl_ishtp_cl_reset will not get called when ecl_ishtp_cl_remove() get called ?
> Otherwise these
> 2 works might get requeued at this point.
> 
The current platform enables any notification from PSE FW to this driver (ecl_ishtp_cl_event_cb() gets called only 
after first ACPI command which is an ENABLE_EVENTS message to FW) after acpi_opregion_init()
So this scenario won't happen atleast here. But as far as failsafing the driver from bugs, I'll move them after.
Thank you for pointing out.

> > +
> > +	ishtp_set_connection_state(ecl_ishtp_cl,
> ISHTP_CL_DISCONNECTING);
> 
> This is not done by the ISH bus code ? I guess that also means that before
> this the ecl_ishtp_cl_event_cb and ecl_ishtp_cl_reset callbacks might still get
> called ?
> 
> If so then the cancel_work_sync needs to be done later.

ISHTP_CL_DISCONNECTING is not done by the bus. This API is exposed to be called by the client driver.
That being said,  cancel_work_sync() needs to be called after this. I'll include this change as well in V3.

> 
> Regards,
> 
> Hans
> 
> 
> > +	ishtp_cl_disconnect(ecl_ishtp_cl);
> > +	ecl_ishtp_cl_deinit(ecl_ishtp_cl);
> > +}
> > +
> > +static int ecl_ishtp_cl_reset(struct ishtp_cl_device *cl_device) {
> > +	struct ishtp_cl *ecl_ishtp_cl = ishtp_get_drvdata(cl_device);
> > +	struct ishtp_opregion_dev *opr_dev =
> > +		ishtp_get_client_data(ecl_ishtp_cl);
> > +
> > +	schedule_work(&opr_dev->reset_work);
> > +
> > +	return 0;
> > +}
> > +
> > +static int ecl_ishtp_cl_suspend(struct device *device) {
> > +	struct ishtp_cl_device *cl_device = ishtp_dev_to_cl_device(device);
> > +	struct ishtp_cl *ecl_ishtp_cl = ishtp_get_drvdata(cl_device);
> > +	struct ishtp_opregion_dev *opr_dev =
> > +		ishtp_get_client_data(ecl_ishtp_cl);
> > +
> > +	if (acpi_target_system_state() == ACPI_STATE_S0)
> > +		return 0;
> > +
> > +	acpi_opregion_deinit(opr_dev);
> > +	ecl_ish_cl_enable_events(opr_dev, false);
> > +
> > +	return 0;
> > +}
> > +
> > +static int ecl_ishtp_cl_resume(struct device *device) {
> > +	/* A reset is expected to call after an Sx. At this point
> > +	 * we are not sure if the link is up or not to restore anything,
> > +	 * so do nothing in resume path
> > +	 */
> > +	return 0;
> > +}
> > +
> > +static const struct dev_pm_ops ecl_ishtp_pm_ops = {
> > +	.suspend = ecl_ishtp_cl_suspend,
> > +	.resume = ecl_ishtp_cl_resume,
> > +};
> > +
> > +static struct ishtp_cl_driver ecl_ishtp_cl_driver = {
> > +	.name = "ishtp-eclite",
> > +	.guid = &ecl_ishtp_guid,
> > +	.probe = ecl_ishtp_cl_probe,
> > +	.remove = ecl_ishtp_cl_remove,
> > +	.reset = ecl_ishtp_cl_reset,
> > +	.driver.pm = &ecl_ishtp_pm_ops,
> > +};
> > +
> > +static int __init ecl_ishtp_init(void) {
> > +	return ishtp_cl_driver_register(&ecl_ishtp_cl_driver, THIS_MODULE);
> > +}
> > +
> > +static void __exit ecl_ishtp_exit(void) {
> > +	return ishtp_cl_driver_unregister(&ecl_ishtp_cl_driver);
> > +}
> > +
> > +late_initcall(ecl_ishtp_init);
> > +module_exit(ecl_ishtp_exit);
> > +
> > +MODULE_DESCRIPTION("ISH ISHTP eclite client opregion driver");
> > +MODULE_AUTHOR("K Naduvalath, Sumesh
> > +<sumesh.k.naduvalath@intel.com>");
> > +
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_ALIAS("ishtp:*");
> >

I'll put through some tests and submit V3 if you don't have any other comments.