mei: gsc_proxy: add gsc proxy driver

Add GSC proxy driver. It to allows messaging between GSC component
on Intel graphics card and CSE device.

Cc: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230502163854.317653-3-daniele.ceraolospurio@intel.com

drivers/misc/mei/Kconfig

@@ -62,4 +62,4 @@ config INTEL_MEI_GSC
 
 source "drivers/misc/mei/hdcp/Kconfig"
 source "drivers/misc/mei/pxp/Kconfig"
-
+source "drivers/misc/mei/gsc_proxy/Kconfig"

drivers/misc/mei/Makefile

@@ -30,3 +30,4 @@ CFLAGS_mei-trace.o = -I$(src)
 
 obj-$(CONFIG_INTEL_MEI_HDCP) += hdcp/
 obj-$(CONFIG_INTEL_MEI_PXP) += pxp/
+obj-$(CONFIG_INTEL_MEI_GSC_PROXY) += gsc_proxy/

drivers/misc/mei/gsc_proxy/Kconfig

@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2022-2023, Intel Corporation. All rights reserved.
+#
+config INTEL_MEI_GSC_PROXY
+	tristate "Intel GSC Proxy services of ME Interface"
+	select INTEL_MEI_ME
+	depends on DRM_I915
+	help
+         MEI Support for GSC Proxy Services on Intel platforms.
+
+         MEI GSC proxy enables messaging between GSC service on
+         Intel graphics card and services on CSE (MEI) firmware
+         residing SoC or PCH.
+

drivers/misc/mei/gsc_proxy/Makefile

@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2022-2023, Intel Corporation. All rights reserved.
+#
+# Makefile - GSC Proxy client driver for Intel MEI Bus Driver.
+
+obj-$(CONFIG_INTEL_MEI_GSC_PROXY) += mei_gsc_proxy.o

drivers/misc/mei/gsc_proxy/mei_gsc_proxy.c

@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022-2023 Intel Corporation
+ */
+
+/**
+ * DOC: MEI_GSC_PROXY Client Driver
+ *
+ * The mei_gsc_proxy driver acts as a translation layer between
+ * proxy user (I915) and ME FW by proxying messages to ME FW
+ */
+
+#include <linux/component.h>
+#include <linux/mei_cl_bus.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/uuid.h>
+#include <drm/drm_connector.h>
+#include <drm/i915_component.h>
+#include <drm/i915_gsc_proxy_mei_interface.h>
+
+/**
+ * mei_gsc_proxy_send - Sends a proxy message to ME FW.
+ * @dev: device corresponding to the mei_cl_device
+ * @buf: a message buffer to send
+ * @size: size of the message
+ * Return: bytes sent on Success, <0 on Failure
+ */
+static int mei_gsc_proxy_send(struct device *dev, const void *buf, size_t size)
+{
+	ssize_t ret;
+
+	if (!dev || !buf)
+		return -EINVAL;
+
+	ret = mei_cldev_send(to_mei_cl_device(dev), buf, size);
+	if (ret < 0)
+		dev_dbg(dev, "mei_cldev_send failed. %zd\n", ret);
+
+	return ret;
+}
+
+/**
+ * mei_gsc_proxy_recv - Receives a proxy message from ME FW.
+ * @dev: device corresponding to the mei_cl_device
+ * @buf: a message buffer to contain the received message
+ * @size: size of the buffer
+ * Return: bytes received on Success, <0 on Failure
+ */
+static int mei_gsc_proxy_recv(struct device *dev, void *buf, size_t size)
+{
+	ssize_t ret;
+
+	if (!dev || !buf)
+		return -EINVAL;
+
+	ret = mei_cldev_recv(to_mei_cl_device(dev), buf, size);
+	if (ret < 0)
+		dev_dbg(dev, "mei_cldev_recv failed. %zd\n", ret);
+
+	return ret;
+}
+
+static const struct i915_gsc_proxy_component_ops mei_gsc_proxy_ops = {
+	.owner = THIS_MODULE,
+	.send = mei_gsc_proxy_send,
+	.recv = mei_gsc_proxy_recv,
+};
+
+static int mei_component_master_bind(struct device *dev)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	struct i915_gsc_proxy_component *comp_master = mei_cldev_get_drvdata(cldev);
+
+	comp_master->ops = &mei_gsc_proxy_ops;
+	comp_master->mei_dev = dev;
+	return component_bind_all(dev, comp_master);
+}
+
+static void mei_component_master_unbind(struct device *dev)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	struct i915_gsc_proxy_component *comp_master = mei_cldev_get_drvdata(cldev);
+
+	component_unbind_all(dev, comp_master);
+}
+
+static const struct component_master_ops mei_component_master_ops = {
+	.bind = mei_component_master_bind,
+	.unbind = mei_component_master_unbind,
+};
+
+/**
+ * mei_gsc_proxy_component_match - compare function for matching mei.
+ *
+ *    The function checks if the device is pci device and
+ *    Intel VGA adapter, the subcomponent is SW Proxy
+ *    and the parent of MEI PCI and the parent of VGA are the same PCH device.
+ *
+ * @dev: master device
+ * @subcomponent: subcomponent to match (I915_COMPONENT_SWPROXY)
+ * @data: compare data (mei pci parent)
+ *
+ * Return:
+ * * 1 - if components match
+ * * 0 - otherwise
+ */
+static int mei_gsc_proxy_component_match(struct device *dev, int subcomponent,
+					 void *data)
+{
+	struct pci_dev *pdev;
+
+	if (!dev_is_pci(dev))
+		return 0;
+
+	pdev = to_pci_dev(dev);
+
+	if (pdev->class != (PCI_CLASS_DISPLAY_VGA << 8) ||
+	    pdev->vendor != PCI_VENDOR_ID_INTEL)
+		return 0;
+
+	if (subcomponent != I915_COMPONENT_GSC_PROXY)
+		return 0;
+
+	return component_compare_dev(dev->parent, ((struct device *)data)->parent);
+}
+
+static int mei_gsc_proxy_probe(struct mei_cl_device *cldev,
+			       const struct mei_cl_device_id *id)
+{
+	struct i915_gsc_proxy_component *comp_master;
+	struct component_match *master_match = NULL;
+	int ret;
+
+	ret = mei_cldev_enable(cldev);
+	if (ret < 0) {
+		dev_err(&cldev->dev, "mei_cldev_enable Failed. %d\n", ret);
+		goto enable_err_exit;
+	}
+
+	comp_master = kzalloc(sizeof(*comp_master), GFP_KERNEL);
+	if (!comp_master) {
+		ret = -ENOMEM;
+		goto err_exit;
+	}
+
+	component_match_add_typed(&cldev->dev, &master_match,
+				  mei_gsc_proxy_component_match, cldev->dev.parent);
+	if (IS_ERR_OR_NULL(master_match)) {
+		ret = -ENOMEM;
+		goto err_exit;
+	}
+
+	mei_cldev_set_drvdata(cldev, comp_master);
+	ret = component_master_add_with_match(&cldev->dev,
+					      &mei_component_master_ops,
+					      master_match);
+	if (ret < 0) {
+		dev_err(&cldev->dev, "Master comp add failed %d\n", ret);
+		goto err_exit;
+	}
+
+	return 0;
+
+err_exit:
+	mei_cldev_set_drvdata(cldev, NULL);
+	kfree(comp_master);
+	mei_cldev_disable(cldev);
+enable_err_exit:
+	return ret;
+}
+
+static void mei_gsc_proxy_remove(struct mei_cl_device *cldev)
+{
+	struct i915_gsc_proxy_component *comp_master = mei_cldev_get_drvdata(cldev);
+	int ret;
+
+	component_master_del(&cldev->dev, &mei_component_master_ops);
+	kfree(comp_master);
+	mei_cldev_set_drvdata(cldev, NULL);
+
+	ret = mei_cldev_disable(cldev);
+	if (ret)
+		dev_warn(&cldev->dev, "mei_cldev_disable() failed %d\n", ret);
+}
+
+#define MEI_UUID_GSC_PROXY UUID_LE(0xf73db04, 0x97ab, 0x4125, \
+				   0xb8, 0x93, 0xe9, 0x4, 0xad, 0xd, 0x54, 0x64)
+
+static struct mei_cl_device_id mei_gsc_proxy_tbl[] = {
+	{ .uuid = MEI_UUID_GSC_PROXY, .version = MEI_CL_VERSION_ANY },
+	{ }
+};
+MODULE_DEVICE_TABLE(mei, mei_gsc_proxy_tbl);
+
+static struct mei_cl_driver mei_gsc_proxy_driver = {
+	.id_table = mei_gsc_proxy_tbl,
+	.name = KBUILD_MODNAME,
+	.probe = mei_gsc_proxy_probe,
+	.remove	= mei_gsc_proxy_remove,
+};
+
+module_mei_cl_driver(mei_gsc_proxy_driver);
+
+MODULE_AUTHOR("Intel Corporation");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("MEI GSC PROXY");