drm/xe/pm: Wire up suspend/resume for I2C controller

Wire up suspend/resume handles for I2C controller to match its power
state with SGUnit.

Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Karthik Poosa <karthik.poosa@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://lore.kernel.org/r/20250701122252.2590230-5-heikki.krogerus@linux.intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Author: raagjadav

drivers/gpu/drm/xe/regs/xe_i2c_regs.h

@@ -2,6 +2,8 @@
 #ifndef _XE_I2C_REGS_H_
 #define _XE_I2C_REGS_H_
 
+#include <linux/pci_regs.h>
+
 #include "xe_reg_defs.h"
 #include "xe_regs.h"
 
@@ -12,4 +14,7 @@
 #define REG_SG_REMAP_ADDR_PREFIX	XE_REG(SOC_BASE + 0x0164)
 #define REG_SG_REMAP_ADDR_POSTFIX	XE_REG(SOC_BASE + 0x0168)
 
+#define I2C_CONFIG_CMD			XE_REG(I2C_CONFIG_SPACE_OFFSET + PCI_COMMAND)
+#define I2C_CONFIG_PMCSR		XE_REG(I2C_CONFIG_SPACE_OFFSET + 0x84)
+
 #endif /* _XE_I2C_REGS_H_ */

drivers/gpu/drm/xe/xe_i2c.c

@@ -226,6 +226,31 @@ static const struct regmap_config i2c_regmap_config = {
 	.fast_io = true,
 };
 
+void xe_i2c_pm_suspend(struct xe_device *xe)
+{
+	struct xe_mmio *mmio = xe_root_tile_mmio(xe);
+
+	if (!xe->i2c || xe->i2c->ep.cookie != XE_I2C_EP_COOKIE_DEVICE)
+		return;
+
+	xe_mmio_rmw32(mmio, I2C_CONFIG_PMCSR, PCI_PM_CTRL_STATE_MASK, (__force u32)PCI_D3hot);
+	drm_dbg(&xe->drm, "pmcsr: 0x%08x\n", xe_mmio_read32(mmio, I2C_CONFIG_PMCSR));
+}
+
+void xe_i2c_pm_resume(struct xe_device *xe, bool d3cold)
+{
+	struct xe_mmio *mmio = xe_root_tile_mmio(xe);
+
+	if (!xe->i2c || xe->i2c->ep.cookie != XE_I2C_EP_COOKIE_DEVICE)
+		return;
+
+	if (d3cold)
+		xe_mmio_rmw32(mmio, I2C_CONFIG_CMD, 0, PCI_COMMAND_MEMORY);
+
+	xe_mmio_rmw32(mmio, I2C_CONFIG_PMCSR, PCI_PM_CTRL_STATE_MASK, (__force u32)PCI_D0);
+	drm_dbg(&xe->drm, "pmcsr: 0x%08x\n", xe_mmio_read32(mmio, I2C_CONFIG_PMCSR));
+}
+
 static void xe_i2c_remove(void *data)
 {
 	struct xe_i2c *i2c = data;
@@ -270,6 +295,10 @@ int xe_i2c_probe(struct xe_device *xe)
 	i2c->mmio = xe_root_tile_mmio(xe);
 	i2c->drm_dev = drm_dev;
 	i2c->ep = ep;
+	xe->i2c = i2c;
+
+	/* PCI PM isn't aware of this device, bring it up and match it with SGUnit state. */
+	xe_i2c_pm_resume(xe, true);
 
 	regmap = devm_regmap_init(drm_dev, NULL, i2c, &i2c_regmap_config);
 	if (IS_ERR(regmap))

drivers/gpu/drm/xe/xe_i2c.h

@@ -50,9 +50,13 @@ struct xe_i2c {
 #if IS_ENABLED(CONFIG_I2C)
 int xe_i2c_probe(struct xe_device *xe);
 void xe_i2c_irq_handler(struct xe_device *xe, u32 master_ctl);
+void xe_i2c_pm_suspend(struct xe_device *xe);
+void xe_i2c_pm_resume(struct xe_device *xe, bool d3cold);
 #else
 static inline int xe_i2c_probe(struct xe_device *xe) { return 0; }
 static inline void xe_i2c_irq_handler(struct xe_device *xe, u32 master_ctl) { }
+static inline void xe_i2c_pm_suspend(struct xe_device *xe) { }
+static inline void xe_i2c_pm_resume(struct xe_device *xe, bool d3cold) { }
 #endif
 
 #endif

drivers/gpu/drm/xe/xe_pm.c

@@ -19,6 +19,7 @@
 #include "xe_ggtt.h"
 #include "xe_gt.h"
 #include "xe_guc.h"
+#include "xe_i2c.h"
 #include "xe_irq.h"
 #include "xe_pcode.h"
 #include "xe_pxp.h"
@@ -146,6 +147,8 @@ int xe_pm_suspend(struct xe_device *xe)
 
 	xe_display_pm_suspend_late(xe);
 
+	xe_i2c_pm_suspend(xe);
+
 	drm_dbg(&xe->drm, "Device suspended\n");
 	return 0;
 
@@ -190,6 +193,8 @@ int xe_pm_resume(struct xe_device *xe)
 	if (err)
 		goto err;
 
+	xe_i2c_pm_resume(xe, xe->d3cold.allowed);
+
 	xe_irq_resume(xe);
 
 	for_each_gt(gt, xe, id)
@@ -487,6 +492,8 @@ int xe_pm_runtime_suspend(struct xe_device *xe)
 
 	xe_display_pm_runtime_suspend_late(xe);
 
+	xe_i2c_pm_suspend(xe);
+
 	xe_rpm_lockmap_release(xe);
 	xe_pm_write_callback_task(xe, NULL);
 	return 0;
@@ -534,6 +541,8 @@ int xe_pm_runtime_resume(struct xe_device *xe)
 			goto out;
 	}
 
+	xe_i2c_pm_resume(xe, xe->d3cold.allowed);
+
 	xe_irq_resume(xe);
 
 	for_each_gt(gt, xe, id)