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

1 files changed, 194 insertions, 0 deletions

diff --git a/drivers/misc/mei/gsc-me.c b/drivers/misc/mei/gsc-me.c
new file mode 100644
index 000000000000..c474094645a0
--- /dev/null
+++ b/drivers/misc/mei/gsc-me.c
@@ -0,0 +1,194 @@
+// 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");