mei: add support for graphics system controller (gsc) devices

GSC is a graphics system controller, based on CSE, it provides
a chassis controller for graphics discrete cards, as well as it
supports media protection on selected devices.

mei_gsc binds to a auxiliary devices exposed by Intel discrete
driver i915.

v2: fix error check in mei_gsc_probe
v3: update MODULE_LICENSE ("GPL" is preferred over "GPL v2" and they
    both map to GPL version 2)
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com> #v3
Link: https://patchwork.freedesktop.org/patch/msgid/20220419193314.526966-3-daniele.ceraolospurio@intel.com

drivers/misc/mei/Kconfig

@@ -46,6 +46,20 @@ config INTEL_MEI_TXE
 	  Supported SoCs:
 	  Intel Bay Trail
 
+config INTEL_MEI_GSC
+	tristate "Intel MEI GSC embedded device"
+	depends on INTEL_MEI
+	depends on INTEL_MEI_ME
+	depends on X86 && PCI
+	depends on DRM_I915
+	help
+	  Intel auxiliary driver for GSC devices embedded in Intel graphics devices.
+
+	  An MEI device here called GSC can be embedded in an
+	  Intel graphics devices, to support a range of chassis
+	  tasks such as graphics card firmware update and security
+	  tasks.
+
 source "drivers/misc/mei/hdcp/Kconfig"
 source "drivers/misc/mei/pxp/Kconfig"
 

drivers/misc/mei/Makefile

@@ -18,6 +18,9 @@ obj-$(CONFIG_INTEL_MEI_ME) += mei-me.o
 mei-me-objs := pci-me.o
 mei-me-objs += hw-me.o
 
+obj-$(CONFIG_INTEL_MEI_GSC) += mei-gsc.o
+mei-gsc-objs := gsc-me.o
+
 obj-$(CONFIG_INTEL_MEI_TXE) += mei-txe.o
 mei-txe-objs := pci-txe.o
 mei-txe-objs += hw-txe.o

drivers/misc/mei/gsc-me.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright(c) 2019-2022, Intel Corporation. All rights reserved.
+ *
+ * Intel Management Engine Interface (Intel MEI) Linux driver
+ */
+
+#include <linux/module.h>
+#include <linux/mei_aux.h>
+#include <linux/device.h>
+#include <linux/irqreturn.h>
+#include <linux/jiffies.h>
+#include <linux/ktime.h>
+#include <linux/delay.h>
+#include <linux/pm_runtime.h>
+
+#include "mei_dev.h"
+#include "hw-me.h"
+#include "hw-me-regs.h"
+
+#include "mei-trace.h"
+
+#define MEI_GSC_RPM_TIMEOUT 500
+
+static int mei_gsc_read_hfs(const struct mei_device *dev, int where, u32 *val)
+{
+	struct mei_me_hw *hw = to_me_hw(dev);
+
+	*val = ioread32(hw->mem_addr + where + 0xC00);
+
+	return 0;
+}
+
+static int mei_gsc_probe(struct auxiliary_device *aux_dev,
+			 const struct auxiliary_device_id *aux_dev_id)
+{
+	struct mei_aux_device *adev = auxiliary_dev_to_mei_aux_dev(aux_dev);
+	struct mei_device *dev;
+	struct mei_me_hw *hw;
+	struct device *device;
+	const struct mei_cfg *cfg;
+	int ret;
+
+	cfg = mei_me_get_cfg(aux_dev_id->driver_data);
+	if (!cfg)
+		return -ENODEV;
+
+	device = &aux_dev->dev;
+
+	dev = mei_me_dev_init(device, cfg);
+	if (!dev) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	hw = to_me_hw(dev);
+	hw->mem_addr = devm_ioremap_resource(device, &adev->bar);
+	if (IS_ERR(hw->mem_addr)) {
+		dev_err(device, "mmio not mapped\n");
+		ret = PTR_ERR(hw->mem_addr);
+		goto err;
+	}
+
+	hw->irq = adev->irq;
+	hw->read_fws = mei_gsc_read_hfs;
+
+	dev_set_drvdata(device, dev);
+
+	ret = devm_request_threaded_irq(device, hw->irq,
+					mei_me_irq_quick_handler,
+					mei_me_irq_thread_handler,
+					IRQF_ONESHOT, KBUILD_MODNAME, dev);
+	if (ret) {
+		dev_err(device, "irq register failed %d\n", ret);
+		goto err;
+	}
+
+	pm_runtime_get_noresume(device);
+	pm_runtime_set_active(device);
+	pm_runtime_enable(device);
+
+	if (mei_start(dev)) {
+		dev_err(device, "init hw failure.\n");
+		ret = -ENODEV;
+		goto irq_err;
+	}
+
+	pm_runtime_set_autosuspend_delay(device, MEI_GSC_RPM_TIMEOUT);
+	pm_runtime_use_autosuspend(device);
+
+	ret = mei_register(dev, device);
+	if (ret)
+		goto register_err;
+
+	pm_runtime_put_noidle(device);
+	return 0;
+
+register_err:
+	mei_stop(dev);
+irq_err:
+	devm_free_irq(device, hw->irq, dev);
+
+err:
+	dev_err(device, "probe failed: %d\n", ret);
+	dev_set_drvdata(device, NULL);
+	return ret;
+}
+
+static void mei_gsc_remove(struct auxiliary_device *aux_dev)
+{
+	struct mei_device *dev;
+	struct mei_me_hw *hw;
+
+	dev = dev_get_drvdata(&aux_dev->dev);
+	if (!dev)
+		return;
+
+	hw = to_me_hw(dev);
+
+	mei_stop(dev);
+
+	mei_deregister(dev);
+
+	pm_runtime_disable(&aux_dev->dev);
+
+	mei_disable_interrupts(dev);
+	devm_free_irq(&aux_dev->dev, hw->irq, dev);
+}
+
+static int __maybe_unused mei_gsc_pm_suspend(struct device *device)
+{
+	struct mei_device *dev = dev_get_drvdata(device);
+
+	if (!dev)
+		return -ENODEV;
+
+	mei_stop(dev);
+
+	mei_disable_interrupts(dev);
+
+	return 0;
+}
+
+static int __maybe_unused mei_gsc_pm_resume(struct device *device)
+{
+	struct mei_device *dev = dev_get_drvdata(device);
+	int err;
+
+	if (!dev)
+		return -ENODEV;
+
+	err = mei_restart(dev);
+	if (err)
+		return err;
+
+	/* Start timer if stopped in suspend */
+	schedule_delayed_work(&dev->timer_work, HZ);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(mei_gsc_pm_ops, mei_gsc_pm_suspend, mei_gsc_pm_resume);
+
+static const struct auxiliary_device_id mei_gsc_id_table[] = {
+	{
+		.name = "i915.mei-gsc",
+		.driver_data = MEI_ME_GSC_CFG,
+
+	},
+	{
+		.name = "i915.mei-gscfi",
+		.driver_data = MEI_ME_GSCFI_CFG,
+	},
+	{
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(auxiliary, mei_gsc_id_table);
+
+static struct auxiliary_driver mei_gsc_driver = {
+	.probe	= mei_gsc_probe,
+	.remove = mei_gsc_remove,
+	.driver = {
+		/* auxiliary_driver_register() sets .name to be the modname */
+		.pm = &mei_gsc_pm_ops,
+	},
+	.id_table = mei_gsc_id_table
+};
+module_auxiliary_driver(mei_gsc_driver);
+
+MODULE_AUTHOR("Intel Corporation");
+MODULE_ALIAS("auxiliary:i915.mei-gsc");
+MODULE_ALIAS("auxiliary:i915.mei-gscfi");
+MODULE_LICENSE("GPL");

drivers/misc/mei/hw-me.c

@@ -1226,6 +1226,7 @@ irqreturn_t mei_me_irq_quick_handler(int irq, void *dev_id)
 	me_intr_disable(dev, hcsr);
 	return IRQ_WAKE_THREAD;
 }
+EXPORT_SYMBOL_GPL(mei_me_irq_quick_handler);
 
 /**
  * mei_me_irq_thread_handler - function called after ISR to handle the interrupt
@@ -1326,6 +1327,7 @@ irqreturn_t mei_me_irq_thread_handler(int irq, void *dev_id)
 	mutex_unlock(&dev->device_lock);
 	return IRQ_HANDLED;
 }
+EXPORT_SYMBOL_GPL(mei_me_irq_thread_handler);
 
 static const struct mei_hw_ops mei_me_hw_ops = {
 
@@ -1440,6 +1442,12 @@ static bool mei_me_fw_type_sps_ign(const struct pci_dev *pdev)
 #define MEI_CFG_KIND_ITOUCH                     \
 	.kind = "itouch"
 
+#define MEI_CFG_TYPE_GSC                        \
+	.kind = "gsc"
+
+#define MEI_CFG_TYPE_GSCFI                      \
+	.kind = "gscfi"
+
 #define MEI_CFG_FW_SPS_IGN                      \
 	.quirk_probe = mei_me_fw_type_sps_ign
 
@@ -1572,6 +1580,18 @@ static const struct mei_cfg mei_me_pch15_sps_cfg = {
 	MEI_CFG_FW_SPS_IGN,
 };
 
+/* Graphics System Controller */
+static const struct mei_cfg mei_me_gsc_cfg = {
+	MEI_CFG_TYPE_GSC,
+	MEI_CFG_PCH8_HFS,
+};
+
+/* Graphics System Controller Firmware Interface */
+static const struct mei_cfg mei_me_gscfi_cfg = {
+	MEI_CFG_TYPE_GSCFI,
+	MEI_CFG_PCH8_HFS,
+};
+
 /*
  * mei_cfg_list - A list of platform platform specific configurations.
  * Note: has to be synchronized with  enum mei_cfg_idx.
@@ -1592,6 +1612,8 @@ static const struct mei_cfg *const mei_cfg_list[] = {
 	[MEI_ME_PCH12_SPS_ITOUCH_CFG] = &mei_me_pch12_itouch_sps_cfg,
 	[MEI_ME_PCH15_CFG] = &mei_me_pch15_cfg,
 	[MEI_ME_PCH15_SPS_CFG] = &mei_me_pch15_sps_cfg,
+	[MEI_ME_GSC_CFG] = &mei_me_gsc_cfg,
+	[MEI_ME_GSCFI_CFG] = &mei_me_gscfi_cfg,
 };
 
 const struct mei_cfg *mei_me_get_cfg(kernel_ulong_t idx)
@@ -1602,7 +1624,8 @@ const struct mei_cfg *mei_me_get_cfg(kernel_ulong_t idx)
 		return NULL;
 
 	return mei_cfg_list[idx];
-};
+}
+EXPORT_SYMBOL_GPL(mei_me_get_cfg);
 
 /**
  * mei_me_dev_init - allocates and initializes the mei device structure
@@ -1637,4 +1660,4 @@ struct mei_device *mei_me_dev_init(struct device *parent,
 
 	return dev;
 }
-
+EXPORT_SYMBOL_GPL(mei_me_dev_init);

drivers/misc/mei/hw-me.h

@@ -112,6 +112,8 @@ enum mei_cfg_idx {
 	MEI_ME_PCH12_SPS_ITOUCH_CFG,
 	MEI_ME_PCH15_CFG,
 	MEI_ME_PCH15_SPS_CFG,
+	MEI_ME_GSC_CFG,
+	MEI_ME_GSCFI_CFG,
 	MEI_ME_NUM_CFG,
 };