Re: [PATCH v10 2/5] mei: add support for graphics system controller (gsc) devices

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On 3/8/2022 8:36 AM, Alexander Usyskin wrote:
From: Tomas Winkler <tomas.winkler@xxxxxxxxx>

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.

Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
---
  drivers/misc/mei/Kconfig  |  14 +++
  drivers/misc/mei/Makefile |   3 +
  drivers/misc/mei/gsc-me.c | 186 ++++++++++++++++++++++++++++++++++++++
  drivers/misc/mei/hw-me.c  |  27 +++++-
  drivers/misc/mei/hw-me.h  |   2 +
  5 files changed, 230 insertions(+), 2 deletions(-)
  create mode 100644 drivers/misc/mei/gsc-me.c

diff --git a/drivers/misc/mei/Kconfig b/drivers/misc/mei/Kconfig
index 0e0bcd0da852..d21486d69df2 100644
--- a/drivers/misc/mei/Kconfig
+++ b/drivers/misc/mei/Kconfig
@@ -46,6 +46,20 @@ config INTEL_MEI_TXE
  	  Supported SoCs:
  	  Intel Bay Trail
+config INTEL_MEI_GSC

On platforms with a GSC, INTEL_MEI_PXP depends on INTEL_MEI_GSC. Are you planning to add that dependency once the HECI1/PXP interface is exposed, or are you expecting i915 to check for both?

+	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"
diff --git a/drivers/misc/mei/Makefile b/drivers/misc/mei/Makefile
index d8e5165917f2..fb740d754900 100644
--- a/drivers/misc/mei/Makefile
+++ b/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
diff --git a/drivers/misc/mei/gsc-me.c b/drivers/misc/mei/gsc-me.c
new file mode 100644
index 000000000000..0afae70e0609
--- /dev/null
+++ b/drivers/misc/mei/gsc-me.c
@@ -0,0 +1,186 @@
+// 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

MEI_ME_RPM_TIMEOUT already exists in hw-me.h with the same value. If you're not expecting them to diverge, we could just re-use the existing one. Not a blocker.

+
+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;

might be worth renaming this variable to mei_dev, to avoid confusion with "device" below. Not a blocker.

+	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 (IS_ERR(dev)) {
+		ret = PTR_ERR(dev);
+		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(&aux_dev->dev, dev);

you have a device = &aux_dev->dev earlier, so you can just use device here.

+
+	ret = devm_request_threaded_irq(device, hw->irq,
+					mei_me_irq_quick_handler,
+					mei_me_irq_thread_handler,
+					IRQF_ONESHOT, KBUILD_MODNAME, dev);

If I'm understanding this correctly, you're tying the irq to the device allocated by i915, so if the probe fails below or the mei_gsc module is unloaded the irq is going to stick around. Probably better to clean it up explicitly, in case we get a spurious interrupt from the HW and i915 propagates it (although that's a very unlikely scenario).

+	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 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);
+
+err:
+	dev_err(device, "probe failed: %d\n", ret);
+	dev_set_drvdata(&aux_dev->dev, NULL);

can use device here as well instead of &aux_dev->dev

+	return ret;
+}
+
+static void mei_gsc_remove(struct auxiliary_device *aux_dev)
+{
+	struct mei_device *dev;
+
+	dev = dev_get_drvdata(&aux_dev->dev);
+	if (!dev)
+		return;
+
+	mei_stop(dev);
+
+	mei_deregister(dev);
+
+	pm_runtime_disable(&aux_dev->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);

Might be worth adding a comment to explain that the interrupts are enabled by the mei_restart and that's why we don't have a mei_interrupts_enable call to match the disable we have in the suspend.

Daniele

+	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 v2");
diff --git a/drivers/misc/mei/hw-me.c b/drivers/misc/mei/hw-me.c
index d3a6c0728645..9748d14849a1 100644
--- a/drivers/misc/mei/hw-me.c
+++ b/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
@@ -1320,6 +1321,7 @@ 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 = { @@ -1433,6 +1435,12 @@ static bool mei_me_fw_type_sps(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                          \
  	.quirk_probe = mei_me_fw_type_sps
@@ -1565,6 +1573,18 @@ static const struct mei_cfg mei_me_pch15_sps_cfg = {
  	MEI_CFG_FW_SPS,
  };
+/* 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.
@@ -1585,6 +1605,8 @@ 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)
@@ -1595,7 +1617,8 @@ 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
@@ -1630,4 +1653,4 @@ struct mei_device *mei_me_dev_init(struct device *parent,
return dev;
  }
-
+EXPORT_SYMBOL_GPL(mei_me_dev_init);
diff --git a/drivers/misc/mei/hw-me.h b/drivers/misc/mei/hw-me.h
index 00a7132ac7a2..a071c645e905 100644
--- a/drivers/misc/mei/hw-me.h
+++ b/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,
  };




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