[RFC,3/6] drm/xe/vrsr: Apis to init and enable VRSR feature

Commit Message

Anshuman Gupta Feb. 24, 2025, 4:48 p.m. UTC

From: Badal Nilawar <[e-mail]>

APIs to enable and initialize VRSR feature.

Signed-off-by: Badal Nilawar <[e-mail]>
Signed-off-by: Anshuman Gupta <[e-mail]>
---
 drivers/gpu/drm/xe/xe_device_types.h |  1 +
 drivers/gpu/drm/xe/xe_pcode_api.h    |  8 +++
 drivers/gpu/drm/xe/xe_pm.c           | 91 ++++++++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_pm.h           |  3 +
 4 files changed, 103 insertions(+)

Comments

Bjorn Helgaas Feb. 24, 2025, 7:43 p.m. UTC | #1

s/Apis/APIs/ in subject to match common usage and use below.

Also perhaps s/Detect vrsr/Detect VRSR/ in previous patch subject to
match this one.

On Mon, Feb 24, 2025 at 10:18:46PM +0530, Anshuman Gupta wrote:
> From: Badal Nilawar <[e-mail]>
> 
> APIs to enable and initialize VRSR feature.

I always think it's nice when the commit log includes the actual names
of the APIs being added so we don't have to grub that out of the
patch.

Patch

diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index c2ab2c91c968..da7946b75cd5 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -7,6 +7,7 @@ 
 #define _XE_DEVICE_TYPES_H_
 
 #include <linux/pci.h>
+#include <linux/pci-acpi.h>
 
 #include <drm/drm_device.h>
 #include <drm/drm_file.h>
diff --git a/drivers/gpu/drm/xe/xe_pcode_api.h b/drivers/gpu/drm/xe/xe_pcode_api.h
index 2bae9afdbd35..17a90b2c6737 100644
--- a/drivers/gpu/drm/xe/xe_pcode_api.h
+++ b/drivers/gpu/drm/xe/xe_pcode_api.h
@@ -42,6 +42,14 @@ 
 #define	    POWER_SETUP_I1_SHIFT		6	/* 10.6 fixed point format */
 #define	    POWER_SETUP_I1_DATA_MASK		REG_GENMASK(15, 0)
 
+#define	  PCODE_D3_VRAM_SELF_REFRESH	0x71
+#define	    PCODE_D3_VRSR_SC_DISABLE	0x0
+#define	    PCODE_D3_VRSR_SC_ENABLE	0x1
+#define     PCODE_D3_VRSR_SC_AUX_PL_AND_PERST_DELAY	0x2
+#define     PCODE_D3_VRSR_PERST_SHIFT	16
+#define	    POWER_D3_VRSR_PSERST_MASK	REG_GENMASK(31, 16)
+#define	    POWER_D3_VRSR_AUX_PL_MASK	REG_GENMASK(15, 0)
+
 #define   PCODE_FREQUENCY_CONFIG		0x6e
 /* Frequency Config Sub Commands (param1) */
 #define     PCODE_MBOX_FC_SC_READ_FUSED_P0	0x0
diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
index dead236355d8..32583651988f 100644
--- a/drivers/gpu/drm/xe/xe_pm.c
+++ b/drivers/gpu/drm/xe/xe_pm.c
@@ -23,6 +23,7 @@ 
 #include "xe_guc.h"
 #include "xe_irq.h"
 #include "xe_mmio.h"
+#include "xe_pcode_api.h"
 #include "xe_pcode.h"
 #include "xe_pxp.h"
 #include "regs/xe_regs.h"
@@ -85,6 +86,92 @@  static struct lockdep_map xe_pm_runtime_nod3cold_map = {
 };
 #endif
 
+/**
+ * xe_pm_init_vrsr - Initialize VRAM self refresh
+ * @xe: The xe device
+ *
+ * This function reads the AUX power and PERST assertion delay from pcode.
+ * Then request host BIOS via ACPI _DSM to grant required AUX power and PERST
+ * assertion delay.
+ *
+ * Return: returns 0 on success and errno on failure
+ */
+int xe_pm_init_vrsr(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;
+	int ret;
+	u32 uval;
+	u32 aux_pwr_limit;
+	u32 perst_delay;
+
+	root_pdev = pcie_find_root_port(pdev);
+	if (!root_pdev)
+		return -EINVAL;
+
+	/* Avoid Illegal Subcommand error */
+	if (xe->info.platform != XE_BATTLEMAGE)
+		return -ENXIO;
+
+	ret = xe_pcode_read(root_tile, PCODE_MBOX(PCODE_D3_VRAM_SELF_REFRESH,
+			    PCODE_D3_VRSR_SC_AUX_PL_AND_PERST_DELAY, 0),
+			    &uval, NULL);
+
+	if (ret)
+		return ret;
+
+	aux_pwr_limit = REG_FIELD_GET(POWER_D3_VRSR_AUX_PL_MASK, uval);
+	perst_delay = REG_FIELD_GET(POWER_D3_VRSR_PSERST_MASK, uval);
+
+	drm_dbg(&xe->drm, "AUX POWER LIMIT =%d\n", aux_pwr_limit);
+	drm_dbg(&xe->drm, "PERST Assertion delay =%d\n", perst_delay);
+
+	ret = pci_acpi_request_d3cold_aux_power(root_pdev, aux_pwr_limit);
+	if (ret)
+		goto vrsr;
+
+	ret = pci_acpi_add_perst_assertion_delay(root_pdev, perst_delay);
+	if (ret)
+		goto vrsr;
+
+	return ret;
+
+vrsr:
+	drm_err(&xe->drm, "ACPI DSM failed, VRSR is not capable\n");
+	xe->d3cold.vrsr_capable = false;
+	return ret;
+}
+
+/**
+ * xe_pm_enable_vrsr - Enable VRAM self refresh
+ * @xe: The xe device.
+ * @enable: true: Enable, false: Disable
+ *
+ * This function enables the VRSR feature in D3Cold path.
+ *
+ * Return: It returns 0 on success and errno on failure.
+ */
+int xe_pm_enable_vrsr(struct xe_device *xe, bool enable)
+{
+	struct xe_tile *root_tile = xe_device_get_root_tile(xe);
+	int ret;
+	u32 uval = 0;
+
+	/* Avoid Illegal Subcommand error */
+	if (xe->info.platform != XE_BATTLEMAGE)
+		return -ENXIO;
+
+	if (enable)
+		ret = xe_pcode_write(root_tile, PCODE_MBOX(PCODE_D3_VRAM_SELF_REFRESH,
+				     PCODE_D3_VRSR_SC_ENABLE, 0), uval);
+	else
+		ret = xe_pcode_write(root_tile, PCODE_MBOX(PCODE_D3_VRAM_SELF_REFRESH,
+				     PCODE_D3_VRSR_SC_DISABLE, 0), uval);
+
+	return ret;
+}
+
 /**
  * xe_rpm_reclaim_safe() - Whether runtime resume can be done from reclaim context
  * @xe: The xe device.
@@ -330,6 +417,10 @@  int xe_pm_init(struct xe_device *xe)
 			return err;
 
 		xe->d3cold.vrsr_capable = xe_pm_vrsr_capable(xe);
+		if (xe->d3cold.vrsr_capable) {
+			drm_dbg(&xe->drm, "vram sr capable\n");
+			xe_pm_init_vrsr(xe);
+		}
 	}
 
 	xe_pm_runtime_init(xe);
diff --git a/drivers/gpu/drm/xe/xe_pm.h b/drivers/gpu/drm/xe/xe_pm.h
index 998d1ed64556..c9f176912b46 100644
--- a/drivers/gpu/drm/xe/xe_pm.h
+++ b/drivers/gpu/drm/xe/xe_pm.h
@@ -35,4 +35,7 @@  bool xe_rpm_reclaim_safe(const struct xe_device *xe);
 struct task_struct *xe_pm_read_callback_task(struct xe_device *xe);
 int xe_pm_module_init(void);
 
+int xe_pm_init_vrsr(struct xe_device *xe);
+int xe_pm_enable_vrsr(struct xe_device *xe, bool enable);
+
 #endif