[PATCH v2] drm/xe/pm: Enable WAKE# support

[Raag Jadav <raag.jadav@intel.com>]

CRI supports signalling the host through WAKE# pin on smbus alerts while
in D3cold. Enable/disable this feature based on device/host configuration.

v2: Make wakeup helper static, drop d3cold argument (Rodrigo)

Signed-off-by: Raag Jadav <raag.jadav@intel.com>
---
 drivers/gpu/drm/xe/xe_device_types.h |  4 ++
 drivers/gpu/drm/xe/xe_pcode_api.h    |  5 +++
 drivers/gpu/drm/xe/xe_pm.c           | 66 ++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index dc17f63f9353..1249ca50a65c 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -517,6 +517,10 @@ struct xe_device {
 		 * Default threshold value is 300mb.
 		 */
 		u32 vram_threshold;
+
+		/** @d3cold.wake: Indicates WAKE# capability of device */
+		u32 wake;
+
 		/** @d3cold.lock: protect vram_threshold */
 		struct mutex lock;
 	} d3cold;
diff --git a/drivers/gpu/drm/xe/xe_pcode_api.h b/drivers/gpu/drm/xe/xe_pcode_api.h
index 92bfcba51e19..3f8d43c1b4fe 100644
--- a/drivers/gpu/drm/xe/xe_pcode_api.h
+++ b/drivers/gpu/drm/xe/xe_pcode_api.h
@@ -50,6 +50,11 @@
 #define	READ_PL_FROM_FW				0x1
 #define	READ_PL_FROM_PCODE			0x0
 
+#define   PCODE_D3COLD_WAKE			0x5A
+#define     READ_MODE				0x0
+#define     WRITE_MODE				0x1
+#define       I2C_WAKE_ENABLE			REG_BIT(1)
+
 #define   PCODE_LATE_BINDING			0x5C
 #define     GET_CAPABILITY_STATUS		0x0
 #define       V1_FAN_SUPPORTED			REG_BIT(0)
diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
index 7b089e6fb63f..04621bbd0b44 100644
--- a/drivers/gpu/drm/xe/xe_pm.c
+++ b/drivers/gpu/drm/xe/xe_pm.c
@@ -7,6 +7,8 @@
 
 #include <linux/fault-inject.h>
 #include <linux/pm_runtime.h>
+#include <linux/pm_wakeup.h>
+#include <linux/string_choices.h>
 #include <linux/suspend.h>
 
 #include <drm/drm_managed.h>
@@ -22,6 +24,7 @@
 #include "xe_i2c.h"
 #include "xe_irq.h"
 #include "xe_late_bind_fw.h"
+#include "xe_pcode_api.h"
 #include "xe_pcode.h"
 #include "xe_pxp.h"
 #include "xe_sriov_vf_ccs.h"
@@ -161,6 +164,29 @@ static void xe_rpm_lockmap_release(const struct xe_device *xe)
 			 &xe_pm_runtime_d3cold_map);
 }
 
+static void xe_pm_set_wakeup(struct xe_device *xe)
+{
+	struct xe_tile *root_tile = xe_device_get_root_tile(xe);
+	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
+	struct pci_dev *root_pdev;
+	bool wakeup;
+	int ret;
+
+	/* Currently WAKE# is supported for I2C only */
+	if (!REG_FIELD_GET(I2C_WAKE_ENABLE, xe->d3cold.wake))
+		return;
+
+	root_pdev = pcie_find_root_port(pdev);
+	wakeup = root_pdev && device_may_wakeup(&root_pdev->dev);
+
+	ret = xe_pcode_write(root_tile, PCODE_MBOX(PCODE_D3COLD_WAKE, WRITE_MODE, 0),
+			     wakeup ? xe->d3cold.wake : 0);
+	if (ret)
+		return;
+
+	drm_dbg(&xe->drm, "WAKE# %s\n", str_enabled_disabled(wakeup));
+}
+
 /**
  * xe_pm_suspend - Helper for System suspend, i.e. S0->S3 / S0->S2idle
  * @xe: xe device instance
@@ -205,6 +231,9 @@ int xe_pm_suspend(struct xe_device *xe)
 
 	xe_i2c_pm_suspend(xe);
 
+	/* Should be the last call in suspend path */
+	xe_pm_set_wakeup(xe);
+
 	drm_dbg(&xe->drm, "Device suspended\n");
 	xe_pm_block_end_signalling();
 
@@ -422,6 +451,38 @@ static int xe_pm_notifier_callback(struct notifier_block *nb,
 	return NOTIFY_DONE;
 }
 
+static void xe_pm_wakeup_init(struct xe_device *xe)
+{
+	struct xe_tile *root_tile = xe_device_get_root_tile(xe);
+	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
+	struct pci_dev *root_pdev;
+	u32 val = 0;
+	int err;
+
+	if (xe->info.platform != XE_CRESCENTISLAND)
+		return;
+
+	err = xe_pcode_read(root_tile, PCODE_MBOX(PCODE_D3COLD_WAKE, READ_MODE, 0), &val, NULL);
+	if (err || !val) {
+		drm_dbg(&xe->drm, "WAKE# not supported by device\n");
+		return;
+	}
+
+	root_pdev = pcie_find_root_port(pdev);
+	if (!root_pdev || !device_can_wakeup(&root_pdev->dev)) {
+		drm_dbg(&xe->drm, "WAKE# not supported by host\n");
+		goto out;
+	}
+
+	if (!xe_i2c_present(xe))
+		val &= ~I2C_WAKE_ENABLE;
+
+	xe->d3cold.wake = val;
+	drm_dbg(&xe->drm, "WAKE# configuration 0x%08x\n", xe->d3cold.wake);
+out:
+	xe_pcode_write(root_tile, PCODE_MBOX(PCODE_D3COLD_WAKE, WRITE_MODE, 0), xe->d3cold.wake);
+}
+
 /**
  * xe_pm_init - Initialize Xe Power Management
  * @xe: xe device instance
@@ -459,6 +520,7 @@ int xe_pm_init(struct xe_device *xe)
 			goto err_unregister;
 	}
 
+	xe_pm_wakeup_init(xe);
 	xe_pm_runtime_init(xe);
 	return 0;
 
@@ -602,6 +664,10 @@ int xe_pm_runtime_suspend(struct xe_device *xe)
 
 	xe_i2c_pm_suspend(xe);
 
+	/* Should be the last call in suspend path */
+	if (xe->d3cold.allowed)
+		xe_pm_set_wakeup(xe);
+
 	xe_rpm_lockmap_release(xe);
 	xe_pm_write_callback_task(xe, NULL);
 	return 0;
-- 
2.34.1