[PATCH v2 21/27] nvdimm/ocxl: Support firmware update via sysfs

["Alastair D'Silva" <alastair@au1.ibm.com>]

From: Alastair D'Silva <alastair@d-silva.org>

This patch allows the firmware of an OpenCAPI SCM card to be update by
writing a firmware file to a file in sysfs.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
---
 drivers/nvdimm/ocxl/Makefile       |   2 +-
 drivers/nvdimm/ocxl/scm.c          |   5 +
 drivers/nvdimm/ocxl/scm_internal.c |  25 +++++
 drivers/nvdimm/ocxl/scm_internal.h |  14 +++
 drivers/nvdimm/ocxl/scm_sysfs.c    | 163 +++++++++++++++++++++++++++++
 5 files changed, 208 insertions(+), 1 deletion(-)
 create mode 100644 drivers/nvdimm/ocxl/scm_sysfs.c

diff --git a/drivers/nvdimm/ocxl/Makefile b/drivers/nvdimm/ocxl/Makefile
index 9b6e31f0eb3e..b172cef39de4 100644
--- a/drivers/nvdimm/ocxl/Makefile
+++ b/drivers/nvdimm/ocxl/Makefile
@@ -4,4 +4,4 @@ ccflags-$(CONFIG_PPC_WERROR)	+= -Werror
 
 obj-$(CONFIG_OCXL_SCM) += ocxlscm.o
 
-ocxlscm-y := scm.o scm_internal.o
+ocxlscm-y := scm.o scm_internal.o scm_sysfs.o
diff --git a/drivers/nvdimm/ocxl/scm.c b/drivers/nvdimm/ocxl/scm.c
index d482b3213a02..8a30c887b5ed 100644
--- a/drivers/nvdimm/ocxl/scm.c
+++ b/drivers/nvdimm/ocxl/scm.c
@@ -1503,6 +1503,11 @@ static int scm_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto err;
 	}
 
+	if (scm_sysfs_add(scm_data)) {
+		dev_err(&pdev->dev, "Could not create SCM sysfs entries\n");
+		goto err;
+	}
+
 	elapsed = 0;
 	timeout = scm_data->readiness_timeout + scm_data->memory_available_timeout;
 	while (!scm_is_usable(scm_data)) {
diff --git a/drivers/nvdimm/ocxl/scm_internal.c b/drivers/nvdimm/ocxl/scm_internal.c
index c405f1d8afb8..8fc849610eaa 100644
--- a/drivers/nvdimm/ocxl/scm_internal.c
+++ b/drivers/nvdimm/ocxl/scm_internal.c
@@ -210,3 +210,28 @@ void scm_warn_status(const struct scm_data *scm_data, const char *message,
 
 	dev_warn(&scm_data->dev, "%s: %s (%x)\n", message, text, status);
 }
+
+void scm_warn_status_fw_update(const struct scm_data *scm_data,
+			       const char *message, u8 status)
+{
+	const char *text;
+
+	switch (status) {
+	case STATUS_FW_UPDATE_BLOCKED:
+		text = "Firmware update is blocked, please try again later";
+		break;
+
+	case STATUS_FW_ARG_INVALID:
+		text = "Internal error in SCM firmware update mechanism";
+		break;
+
+	case STATUS_FW_INVALID:
+		text = "Firmware content is invalid, please verify firmware update file";
+		break;
+
+	default:
+		return scm_warn_status(scm_data, message, status);
+	}
+
+	dev_warn(&scm_data->dev, "%s: %s (%x)\n", message, text, status);
+}
diff --git a/drivers/nvdimm/ocxl/scm_internal.h b/drivers/nvdimm/ocxl/scm_internal.h
index 693fd59f8bde..af19813a7f75 100644
--- a/drivers/nvdimm/ocxl/scm_internal.h
+++ b/drivers/nvdimm/ocxl/scm_internal.h
@@ -137,6 +137,12 @@ struct scm_data {
 			   */
 };
 
+/**
+ * Create sysfs entries for an SCM device
+ * scm_data: The SCM metadata
+ */
+int scm_sysfs_add(struct scm_data *scm_data);
+
 /**
  * scm_chi() - Get the value of the CHI register
  * @scm_data: The SCM metadata
@@ -230,3 +236,11 @@ int scm_ns_response_handled(const struct scm_data *scm_data);
 void scm_warn_status(const struct scm_data *scm_data, const char *message,
 		     u8 status);
 
+/**
+ * scm_warn_status_fw_update() - Emit a kernel warning showing a command status.
+ * @scm_data: a pointer to the SCM device data
+ * @message: A message to accompany the warning
+ * @status: The command status
+ */
+void scm_warn_status_fw_update(const struct scm_data *scm_data,
+			       const char *message, u8 status);
diff --git a/drivers/nvdimm/ocxl/scm_sysfs.c b/drivers/nvdimm/ocxl/scm_sysfs.c
new file mode 100644
index 000000000000..a04e8a74d0c5
--- /dev/null
+++ b/drivers/nvdimm/ocxl/scm_sysfs.c
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright 2018 IBM Corp.
+
+#include <linux/sysfs.h>
+#include <linux/capability.h>
+#include <linux/limits.h>
+#include <linux/firmware.h>
+#include "scm_internal.h"
+
+static ssize_t fw_version_show(struct device *device,
+			       struct device_attribute *attr, char *buf)
+{
+	struct scm_data *scm_data = container_of(device, struct scm_data, dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%s\n", scm_data->fw_version);
+}
+
+#define SCM_FWUPDATE_BLOCK_SIZE	32768
+
+/**
+ * scm_update_firmware() - Write a 32kB block of data to firmware
+ * The block may be less than 32kB if it is the last one
+ *
+ * scm_data the SCM device metadata
+ * offset: the offset of the start of the block
+ * buf: the block data
+ * size: the size of the block
+ */
+static ssize_t scm_update_firmware(struct scm_data *scm_data, size_t offset,
+				   const char *buf, size_t size)
+{
+	int rc;
+	size_t i;
+	u64 val;
+
+	if (size > SCM_FWUPDATE_BLOCK_SIZE)
+		return -EINVAL;
+
+	rc = scm_admin_command_request(scm_data, ADMIN_COMMAND_FW_UPDATE);
+	if (rc)
+		return rc;
+
+	val = (((u64)offset) << 32) | size;
+	rc = ocxl_global_mmio_write64(scm_data->ocxl_afu,
+				      scm_data->admin_command.request_offset + 8,
+				      OCXL_LITTLE_ENDIAN, val);
+	if (rc)
+		return rc;
+
+	for (i = 0; i < size; i += 8) {
+		val = *(u64 *)(buf + i);
+		rc = ocxl_global_mmio_write64(scm_data->ocxl_afu,
+					      scm_data->admin_command.data_offset + i,
+					      OCXL_HOST_ENDIAN, val);
+		if (rc)
+			return rc;
+	}
+
+	rc = scm_admin_command_execute(scm_data);
+	if (rc)
+		return rc;
+
+	rc = scm_admin_command_complete_timeout(scm_data,
+						ADMIN_COMMAND_FW_UPDATE);
+	if (rc < 0) {
+		dev_err(&scm_data->dev, "Firmware update timeout\n");
+		return rc;
+	}
+
+	rc = scm_admin_response(scm_data);
+	if (rc < 0)
+		return rc;
+	if (rc != STATUS_SUCCESS) {
+		scm_warn_status_fw_update(scm_data, "FW Update", rc);
+		return rc;
+	}
+
+	return 0;
+}
+
+/*
+ * Parse out a firmware filename from sysfs, retrieve it's contents and write it
+ * to the SCM device firmware storage
+ */
+static ssize_t fw_update_filename_store(struct device *device,
+					struct device_attribute *attr,
+					const char *buf, size_t size)
+{
+	char path[NAME_MAX+1];
+	const char *end;
+	const struct firmware *firmware = NULL;
+	size_t offset;
+	int rc;
+	struct scm_data *scm_data = container_of(device, struct scm_data, dev);
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	end = strnchr(buf, size, '\n');
+	if (end == NULL)
+		end = buf + strnlen(buf, size);
+
+	if ((end - buf) > NAME_MAX) {
+		dev_err(device, "Firmware filename '%-.*s' too long\n",
+			(int)(end - buf), buf);
+		return -EIO;
+	}
+
+	memcpy(path, buf, end - buf);
+	path[end - buf] = '\0';
+
+	if (request_firmware(&firmware, path, device)) {
+		dev_err(device, "Firmware file %s not found\n", path);
+		return -EIO;
+	}
+
+	if (firmware->size % 8) {
+		release_firmware(firmware);
+		dev_err(device, "Firmware '%s' should be a multiple of 8 bytes", path);
+		return -EINVAL;
+	}
+
+	mutex_lock(&scm_data->admin_command.lock);
+
+	for (offset = 0; offset < firmware->size; offset += SCM_FWUPDATE_BLOCK_SIZE) {
+		size_t remainder = firmware->size - offset;
+		size_t block_size;
+
+		block_size = (remainder > SCM_FWUPDATE_BLOCK_SIZE) ?
+			      SCM_FWUPDATE_BLOCK_SIZE : remainder;
+		rc = scm_update_firmware(scm_data, offset,
+					 firmware->data + offset, block_size);
+		if (rc) {
+			mutex_unlock(&scm_data->admin_command.lock);
+			return -EFAULT;
+		}
+	}
+
+	mutex_unlock(&scm_data->admin_command.lock);
+
+	return size;
+}
+
+static struct device_attribute scm_attrs[] = {
+	__ATTR_RO(fw_version),
+	__ATTR_WO(fw_update_filename),
+};
+
+int scm_sysfs_add(struct scm_data *scm_data)
+{
+	int i, rc;
+
+	for (i = 0; i < ARRAY_SIZE(scm_attrs); i++) {
+		rc = device_create_file(&scm_data->dev, &scm_attrs[i]);
+		if (rc) {
+			for (; --i >= 0;)
+				device_remove_file(&scm_data->dev, &scm_attrs[i]);
+
+			return rc;
+		}
+	}
+	return 0;
+}
-- 
2.23.0
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