drivers/gpu/drm/i915/vlv_suspend.c - linux - Git at Google

 // SPDX-License-Identifier: MIT
 /*
  * Copyright © 2020 Intel Corporation
  */

 #include <linux/string_helpers.h>
 #include <linux/kernel.h>

 #include <drm/drm_print.h>

 #include "i915_drv.h"
 #include "i915_reg.h"
 #include "i915_trace.h"
 #include "i915_utils.h"
 #include "intel_pm.h"
 #include "vlv_suspend.h"

 #include "gt/intel_gt_regs.h"

 struct vlv_s0ix_state {
 	/* GAM */
 	u32 wr_watermark;
 	u32 gfx_prio_ctrl;
 	u32 arb_mode;
 	u32 gfx_pend_tlb0;
 	u32 gfx_pend_tlb1;
 	u32 lra_limits[GEN7_LRA_LIMITS_REG_NUM];
 	u32 media_max_req_count;
 	u32 gfx_max_req_count;
 	u32 render_hwsp;
 	u32 ecochk;
 	u32 bsd_hwsp;
 	u32 blt_hwsp;
 	u32 tlb_rd_addr;

 	/* MBC */
 	u32 g3dctl;
 	u32 gsckgctl;
 	u32 mbctl;

 	/* GCP */
 	u32 ucgctl1;
 	u32 ucgctl3;
 	u32 rcgctl1;
 	u32 rcgctl2;
 	u32 rstctl;
 	u32 misccpctl;

 	/* GPM */
 	u32 gfxpause;
 	u32 rpdeuhwtc;
 	u32 rpdeuc;
 	u32 ecobus;
 	u32 pwrdwnupctl;
 	u32 rp_down_timeout;
 	u32 rp_deucsw;
 	u32 rcubmabdtmr;
 	u32 rcedata;
 	u32 spare2gh;

 	/* Display 1 CZ domain */
 	u32 gt_imr;
 	u32 gt_ier;
 	u32 pm_imr;
 	u32 pm_ier;
 	u32 gt_scratch[GEN7_GT_SCRATCH_REG_NUM];

 	/* GT SA CZ domain */
 	u32 tilectl;
 	u32 gt_fifoctl;
 	u32 gtlc_wake_ctrl;
 	u32 gtlc_survive;
 	u32 pmwgicz;

 	/* Display 2 CZ domain */
 	u32 gu_ctl0;
 	u32 gu_ctl1;
 	u32 pcbr;
 	u32 clock_gate_dis2;
 };

 /*
  * Save all Gunit registers that may be lost after a D3 and a subsequent
  * S0i[R123] transition. The list of registers needing a save/restore is
  * defined in the VLV2_S0IXRegs document. This documents marks all Gunit
  * registers in the following way:
  * - Driver: saved/restored by the driver
  * - Punit : saved/restored by the Punit firmware
  * - No, w/o marking: no need to save/restore, since the register is R/O or
  *                    used internally by the HW in a way that doesn't depend
  *                    keeping the content across a suspend/resume.
  * - Debug : used for debugging
  *
  * We save/restore all registers marked with 'Driver', with the following
  * exceptions:
  * - Registers out of use, including also registers marked with 'Debug'.
  *   These have no effect on the driver's operation, so we don't save/restore
  *   them to reduce the overhead.
  * - Registers that are fully setup by an initialization function called from
  *   the resume path. For example many clock gating and RPS/RC6 registers.
  * - Registers that provide the right functionality with their reset defaults.
  *
  * TODO: Except for registers that based on the above 3 criteria can be safely
  * ignored, we save/restore all others, practically treating the HW context as
  * a black-box for the driver. Further investigation is needed to reduce the
  * saved/restored registers even further, by following the same 3 criteria.
  */
 static void vlv_save_gunit_s0ix_state(struct drm_i915_private *i915)
 {
 	struct vlv_s0ix_state *s = i915->vlv_s0ix_state;
 	struct intel_uncore *uncore = &i915->uncore;
 	int i;

 	if (!s)
 		return;

 	/* GAM 0x4000-0x4770 */
 	s->wr_watermark = intel_uncore_read(uncore, GEN7_WR_WATERMARK);
 	s->gfx_prio_ctrl = intel_uncore_read(uncore, GEN7_GFX_PRIO_CTRL);
 	s->arb_mode = intel_uncore_read(uncore, ARB_MODE);
 	s->gfx_pend_tlb0 = intel_uncore_read(uncore, GEN7_GFX_PEND_TLB0);
 	s->gfx_pend_tlb1 = intel_uncore_read(uncore, GEN7_GFX_PEND_TLB1);

 	for (i = 0; i < ARRAY_SIZE(s->lra_limits); i++)
 		s->lra_limits[i] = intel_uncore_read(uncore, GEN7_LRA_LIMITS(i));

 	s->media_max_req_count = intel_uncore_read(uncore, GEN7_MEDIA_MAX_REQ_COUNT);
 	s->gfx_max_req_count = intel_uncore_read(uncore, GEN7_GFX_MAX_REQ_COUNT);

 	s->render_hwsp = intel_uncore_read(uncore, RENDER_HWS_PGA_GEN7);
 	s->ecochk = intel_uncore_read(uncore, GAM_ECOCHK);
 	s->bsd_hwsp = intel_uncore_read(uncore, BSD_HWS_PGA_GEN7);
 	s->blt_hwsp = intel_uncore_read(uncore, BLT_HWS_PGA_GEN7);

 	s->tlb_rd_addr = intel_uncore_read(uncore, GEN7_TLB_RD_ADDR);

 	/* MBC 0x9024-0x91D0, 0x8500 */
 	s->g3dctl = intel_uncore_read(uncore, VLV_G3DCTL);
 	s->gsckgctl = intel_uncore_read(uncore, VLV_GSCKGCTL);
 	s->mbctl = intel_uncore_read(uncore, GEN6_MBCTL);

 	/* GCP 0x9400-0x9424, 0x8100-0x810C */
 	s->ucgctl1 = intel_uncore_read(uncore, GEN6_UCGCTL1);
 	s->ucgctl3 = intel_uncore_read(uncore, GEN6_UCGCTL3);
 	s->rcgctl1 = intel_uncore_read(uncore, GEN6_RCGCTL1);
 	s->rcgctl2 = intel_uncore_read(uncore, GEN6_RCGCTL2);
 	s->rstctl = intel_uncore_read(uncore, GEN6_RSTCTL);
 	s->misccpctl = intel_uncore_read(uncore, GEN7_MISCCPCTL);

 	/* GPM 0xA000-0xAA84, 0x8000-0x80FC */
 	s->gfxpause = intel_uncore_read(uncore, GEN6_GFXPAUSE);
 	s->rpdeuhwtc = intel_uncore_read(uncore, GEN6_RPDEUHWTC);
 	s->rpdeuc = intel_uncore_read(uncore, GEN6_RPDEUC);
 	s->ecobus = intel_uncore_read(uncore, ECOBUS);
 	s->pwrdwnupctl = intel_uncore_read(uncore, VLV_PWRDWNUPCTL);
 	s->rp_down_timeout = intel_uncore_read(uncore, GEN6_RP_DOWN_TIMEOUT);
 	s->rp_deucsw = intel_uncore_read(uncore, GEN6_RPDEUCSW);
 	s->rcubmabdtmr = intel_uncore_read(uncore, GEN6_RCUBMABDTMR);
 	s->rcedata = intel_uncore_read(uncore, VLV_RCEDATA);
 	s->spare2gh = intel_uncore_read(uncore, VLV_SPAREG2H);

 	/* Display CZ domain, 0x4400C-0x4402C, 0x4F000-0x4F11F */
 	s->gt_imr = intel_uncore_read(uncore, GTIMR);
 	s->gt_ier = intel_uncore_read(uncore, GTIER);
 	s->pm_imr = intel_uncore_read(uncore, GEN6_PMIMR);
 	s->pm_ier = intel_uncore_read(uncore, GEN6_PMIER);

 	for (i = 0; i < ARRAY_SIZE(s->gt_scratch); i++)
 		s->gt_scratch[i] = intel_uncore_read(uncore, GEN7_GT_SCRATCH(i));

 	/* GT SA CZ domain, 0x100000-0x138124 */
 	s->tilectl = intel_uncore_read(uncore, TILECTL);
 	s->gt_fifoctl = intel_uncore_read(uncore, GTFIFOCTL);
 	s->gtlc_wake_ctrl = intel_uncore_read(uncore, VLV_GTLC_WAKE_CTRL);
 	s->gtlc_survive = intel_uncore_read(uncore, VLV_GTLC_SURVIVABILITY_REG);
 	s->pmwgicz = intel_uncore_read(uncore, VLV_PMWGICZ);

 	/* Gunit-Display CZ domain, 0x182028-0x1821CF */
 	s->gu_ctl0 = intel_uncore_read(uncore, VLV_GU_CTL0);
 	s->gu_ctl1 = intel_uncore_read(uncore, VLV_GU_CTL1);
 	s->pcbr = intel_uncore_read(uncore, VLV_PCBR);
 	s->clock_gate_dis2 = intel_uncore_read(uncore, VLV_GUNIT_CLOCK_GATE2);

 	/*
 	 * Not saving any of:
 	 * DFT,		0x9800-0x9EC0
 	 * SARB,	0xB000-0xB1FC
 	 * GAC,		0x5208-0x524C, 0x14000-0x14C000
 	 * PCI CFG
 	 */
 }

 static void vlv_restore_gunit_s0ix_state(struct drm_i915_private *i915)
 {
 	struct vlv_s0ix_state *s = i915->vlv_s0ix_state;
 	struct intel_uncore *uncore = &i915->uncore;
 	int i;

 	if (!s)
 		return;

 	/* GAM 0x4000-0x4770 */
 	intel_uncore_write(uncore, GEN7_WR_WATERMARK, s->wr_watermark);
 	intel_uncore_write(uncore, GEN7_GFX_PRIO_CTRL, s->gfx_prio_ctrl);
 	intel_uncore_write(uncore, ARB_MODE, s->arb_mode | (0xffff << 16));
 	intel_uncore_write(uncore, GEN7_GFX_PEND_TLB0, s->gfx_pend_tlb0);
 	intel_uncore_write(uncore, GEN7_GFX_PEND_TLB1, s->gfx_pend_tlb1);

 	for (i = 0; i < ARRAY_SIZE(s->lra_limits); i++)
 		intel_uncore_write(uncore, GEN7_LRA_LIMITS(i), s->lra_limits[i]);

 	intel_uncore_write(uncore, GEN7_MEDIA_MAX_REQ_COUNT, s->media_max_req_count);
 	intel_uncore_write(uncore, GEN7_GFX_MAX_REQ_COUNT, s->gfx_max_req_count);

 	intel_uncore_write(uncore, RENDER_HWS_PGA_GEN7, s->render_hwsp);
 	intel_uncore_write(uncore, GAM_ECOCHK, s->ecochk);
 	intel_uncore_write(uncore, BSD_HWS_PGA_GEN7, s->bsd_hwsp);
 	intel_uncore_write(uncore, BLT_HWS_PGA_GEN7, s->blt_hwsp);

 	intel_uncore_write(uncore, GEN7_TLB_RD_ADDR, s->tlb_rd_addr);

 	/* MBC 0x9024-0x91D0, 0x8500 */
 	intel_uncore_write(uncore, VLV_G3DCTL, s->g3dctl);
 	intel_uncore_write(uncore, VLV_GSCKGCTL, s->gsckgctl);
 	intel_uncore_write(uncore, GEN6_MBCTL, s->mbctl);

 	/* GCP 0x9400-0x9424, 0x8100-0x810C */
 	intel_uncore_write(uncore, GEN6_UCGCTL1, s->ucgctl1);
 	intel_uncore_write(uncore, GEN6_UCGCTL3, s->ucgctl3);
 	intel_uncore_write(uncore, GEN6_RCGCTL1, s->rcgctl1);
 	intel_uncore_write(uncore, GEN6_RCGCTL2, s->rcgctl2);
 	intel_uncore_write(uncore, GEN6_RSTCTL, s->rstctl);
 	intel_uncore_write(uncore, GEN7_MISCCPCTL, s->misccpctl);

 	/* GPM 0xA000-0xAA84, 0x8000-0x80FC */
 	intel_uncore_write(uncore, GEN6_GFXPAUSE, s->gfxpause);
 	intel_uncore_write(uncore, GEN6_RPDEUHWTC, s->rpdeuhwtc);
 	intel_uncore_write(uncore, GEN6_RPDEUC, s->rpdeuc);
 	intel_uncore_write(uncore, ECOBUS, s->ecobus);
 	intel_uncore_write(uncore, VLV_PWRDWNUPCTL, s->pwrdwnupctl);
 	intel_uncore_write(uncore, GEN6_RP_DOWN_TIMEOUT, s->rp_down_timeout);
 	intel_uncore_write(uncore, GEN6_RPDEUCSW, s->rp_deucsw);
 	intel_uncore_write(uncore, GEN6_RCUBMABDTMR, s->rcubmabdtmr);
 	intel_uncore_write(uncore, VLV_RCEDATA, s->rcedata);
 	intel_uncore_write(uncore, VLV_SPAREG2H, s->spare2gh);

 	/* Display CZ domain, 0x4400C-0x4402C, 0x4F000-0x4F11F */
 	intel_uncore_write(uncore, GTIMR, s->gt_imr);
 	intel_uncore_write(uncore, GTIER, s->gt_ier);
 	intel_uncore_write(uncore, GEN6_PMIMR, s->pm_imr);
 	intel_uncore_write(uncore, GEN6_PMIER, s->pm_ier);

 	for (i = 0; i < ARRAY_SIZE(s->gt_scratch); i++)
 		intel_uncore_write(uncore, GEN7_GT_SCRATCH(i), s->gt_scratch[i]);

 	/* GT SA CZ domain, 0x100000-0x138124 */
 	intel_uncore_write(uncore, TILECTL, s->tilectl);
 	intel_uncore_write(uncore, GTFIFOCTL, s->gt_fifoctl);
 	/*
 	 * Preserve the GT allow wake and GFX force clock bit, they are not
 	 * be restored, as they are used to control the s0ix suspend/resume
 	 * sequence by the caller.
 	 */
 	intel_uncore_rmw(uncore, VLV_GTLC_WAKE_CTRL, ~VLV_GTLC_ALLOWWAKEREQ,
 			 s->gtlc_wake_ctrl & ~VLV_GTLC_ALLOWWAKEREQ);

 	intel_uncore_rmw(uncore, VLV_GTLC_SURVIVABILITY_REG, ~VLV_GFX_CLK_FORCE_ON_BIT,
 			 s->gtlc_survive & ~VLV_GFX_CLK_FORCE_ON_BIT);

 	intel_uncore_write(uncore, VLV_PMWGICZ, s->pmwgicz);

 	/* Gunit-Display CZ domain, 0x182028-0x1821CF */
 	intel_uncore_write(uncore, VLV_GU_CTL0, s->gu_ctl0);
 	intel_uncore_write(uncore, VLV_GU_CTL1, s->gu_ctl1);
 	intel_uncore_write(uncore, VLV_PCBR, s->pcbr);
 	intel_uncore_write(uncore, VLV_GUNIT_CLOCK_GATE2, s->clock_gate_dis2);
 }

 static int vlv_wait_for_pw_status(struct drm_i915_private *i915,
 				  u32 mask, u32 val)
 {
 	i915_reg_t reg = VLV_GTLC_PW_STATUS;
 	u32 reg_value;
 	int ret;

 	/* The HW does not like us polling for PW_STATUS frequently, so
 	 * use the sleeping loop rather than risk the busy spin within
 	 * intel_wait_for_register().
 	 *
 	 * Transitioning between RC6 states should be at most 2ms (see
 	 * valleyview_enable_rps) so use a 3ms timeout.
 	 */
 	ret = wait_for(((reg_value =
 			 intel_uncore_read_notrace(&i915->uncore, reg)) & mask)
 		       == val, 3);

 	/* just trace the final value */
 	trace_i915_reg_rw(false, reg, reg_value, sizeof(reg_value), true);

 	return ret;
 }

 static int vlv_force_gfx_clock(struct drm_i915_private *i915, bool force_on)
 {
 	struct intel_uncore *uncore = &i915->uncore;
 	int err;

 	intel_uncore_rmw(uncore, VLV_GTLC_SURVIVABILITY_REG, VLV_GFX_CLK_FORCE_ON_BIT,
 			 force_on ? VLV_GFX_CLK_FORCE_ON_BIT : 0);

 	if (!force_on)
 		return 0;

 	err = intel_wait_for_register(uncore,
 				      VLV_GTLC_SURVIVABILITY_REG,
 				      VLV_GFX_CLK_STATUS_BIT,
 				      VLV_GFX_CLK_STATUS_BIT,
 				      20);
 	if (err)
 		drm_err(&i915->drm,
 			"timeout waiting for GFX clock force-on (%08x)\n",
 			intel_uncore_read(uncore, VLV_GTLC_SURVIVABILITY_REG));

 	return err;
 }

 static int vlv_allow_gt_wake(struct drm_i915_private *i915, bool allow)
 {
 	struct intel_uncore *uncore = &i915->uncore;
 	u32 mask;
 	u32 val;
 	int err;

 	intel_uncore_rmw(uncore, VLV_GTLC_WAKE_CTRL, VLV_GTLC_ALLOWWAKEREQ,
 			 allow ? VLV_GTLC_ALLOWWAKEREQ : 0);
 	intel_uncore_posting_read(uncore, VLV_GTLC_WAKE_CTRL);

 	mask = VLV_GTLC_ALLOWWAKEACK;
 	val = allow ? mask : 0;

 	err = vlv_wait_for_pw_status(i915, mask, val);
 	if (err)
 		drm_err(&i915->drm, "timeout disabling GT waking\n");

 	return err;
 }

 static void vlv_wait_for_gt_wells(struct drm_i915_private *dev_priv,
 				  bool wait_for_on)
 {
 	u32 mask;
 	u32 val;

 	mask = VLV_GTLC_PW_MEDIA_STATUS_MASK | VLV_GTLC_PW_RENDER_STATUS_MASK;
 	val = wait_for_on ? mask : 0;

 	/*
 	 * RC6 transitioning can be delayed up to 2 msec (see
 	 * valleyview_enable_rps), use 3 msec for safety.
 	 *
 	 * This can fail to turn off the rc6 if the GPU is stuck after a failed
 	 * reset and we are trying to force the machine to sleep.
 	 */
 	if (vlv_wait_for_pw_status(dev_priv, mask, val))
 		drm_dbg(&dev_priv->drm,
 			"timeout waiting for GT wells to go %s\n",
 			str_on_off(wait_for_on));
 }

 static void vlv_check_no_gt_access(struct drm_i915_private *i915)
 {
 	struct intel_uncore *uncore = &i915->uncore;

 	if (!(intel_uncore_read(uncore, VLV_GTLC_PW_STATUS) & VLV_GTLC_ALLOWWAKEERR))
 		return;

 	drm_dbg(&i915->drm, "GT register access while GT waking disabled\n");
 	intel_uncore_write(uncore, VLV_GTLC_PW_STATUS, VLV_GTLC_ALLOWWAKEERR);
 }

 int vlv_suspend_complete(struct drm_i915_private *dev_priv)
 {
 	u32 mask;
 	int err;

 	if (!IS_VALLEYVIEW(dev_priv) && !IS_CHERRYVIEW(dev_priv))
 		return 0;

 	/*
 	 * Bspec defines the following GT well on flags as debug only, so
 	 * don't treat them as hard failures.
 	 */
 	vlv_wait_for_gt_wells(dev_priv, false);

 	mask = VLV_GTLC_RENDER_CTX_EXISTS | VLV_GTLC_MEDIA_CTX_EXISTS;
 	drm_WARN_ON(&dev_priv->drm,
 		    (intel_uncore_read(&dev_priv->uncore, VLV_GTLC_WAKE_CTRL) & mask) != mask);

 	vlv_check_no_gt_access(dev_priv);

 	err = vlv_force_gfx_clock(dev_priv, true);
 	if (err)
 		goto err1;

 	err = vlv_allow_gt_wake(dev_priv, false);
 	if (err)
 		goto err2;

 	vlv_save_gunit_s0ix_state(dev_priv);

 	err = vlv_force_gfx_clock(dev_priv, false);
 	if (err)
 		goto err2;

 	return 0;

 err2:
 	/* For safety always re-enable waking and disable gfx clock forcing */
 	vlv_allow_gt_wake(dev_priv, true);
 err1:
 	vlv_force_gfx_clock(dev_priv, false);

 	return err;
 }

 int vlv_resume_prepare(struct drm_i915_private *dev_priv, bool rpm_resume)
 {
 	int err;
 	int ret;

 	if (!IS_VALLEYVIEW(dev_priv) && !IS_CHERRYVIEW(dev_priv))
 		return 0;

 	/*
 	 * If any of the steps fail just try to continue, that's the best we
 	 * can do at this point. Return the first error code (which will also
 	 * leave RPM permanently disabled).
 	 */
 	ret = vlv_force_gfx_clock(dev_priv, true);

 	vlv_restore_gunit_s0ix_state(dev_priv);

 	err = vlv_allow_gt_wake(dev_priv, true);
 	if (!ret)
 		ret = err;

 	err = vlv_force_gfx_clock(dev_priv, false);
 	if (!ret)
 		ret = err;

 	vlv_check_no_gt_access(dev_priv);

 	if (rpm_resume)
 		intel_init_clock_gating(dev_priv);

 	return ret;
 }

 int vlv_suspend_init(struct drm_i915_private *i915)
 {
 	if (!IS_VALLEYVIEW(i915))
 		return 0;

 	/* we write all the values in the struct, so no need to zero it out */
 	i915->vlv_s0ix_state = kmalloc(sizeof(*i915->vlv_s0ix_state),
 				       GFP_KERNEL);
 	if (!i915->vlv_s0ix_state)
 		return -ENOMEM;

 	return 0;
 }

 void vlv_suspend_cleanup(struct drm_i915_private *i915)
 {
 	if (!i915->vlv_s0ix_state)
 		return;

 	kfree(i915->vlv_s0ix_state);
 	i915->vlv_s0ix_state = NULL;
 }
	// SPDX-License-Identifier: MIT
	/*
	* Copyright © 2020 Intel Corporation
	*/

	#include <linux/string_helpers.h>
	#include <linux/kernel.h>

	#include <drm/drm_print.h>

	#include "i915_drv.h"
	#include "i915_reg.h"
	#include "i915_trace.h"
	#include "i915_utils.h"
	#include "intel_pm.h"
	#include "vlv_suspend.h"

	#include "gt/intel_gt_regs.h"

	struct vlv_s0ix_state {
	/* GAM */
	u32 wr_watermark;
	u32 gfx_prio_ctrl;
	u32 arb_mode;
	u32 gfx_pend_tlb0;
	u32 gfx_pend_tlb1;
	u32 lra_limits[GEN7_LRA_LIMITS_REG_NUM];
	u32 media_max_req_count;
	u32 gfx_max_req_count;
	u32 render_hwsp;
	u32 ecochk;
	u32 bsd_hwsp;
	u32 blt_hwsp;
	u32 tlb_rd_addr;

	/* MBC */
	u32 g3dctl;
	u32 gsckgctl;
	u32 mbctl;

	/* GCP */
	u32 ucgctl1;
	u32 ucgctl3;
	u32 rcgctl1;
	u32 rcgctl2;
	u32 rstctl;
	u32 misccpctl;

	/* GPM */
	u32 gfxpause;
	u32 rpdeuhwtc;
	u32 rpdeuc;
	u32 ecobus;
	u32 pwrdwnupctl;
	u32 rp_down_timeout;
	u32 rp_deucsw;
	u32 rcubmabdtmr;
	u32 rcedata;
	u32 spare2gh;

	/* Display 1 CZ domain */
	u32 gt_imr;
	u32 gt_ier;
	u32 pm_imr;
	u32 pm_ier;
	u32 gt_scratch[GEN7_GT_SCRATCH_REG_NUM];

	/* GT SA CZ domain */
	u32 tilectl;
	u32 gt_fifoctl;
	u32 gtlc_wake_ctrl;
	u32 gtlc_survive;
	u32 pmwgicz;

	/* Display 2 CZ domain */
	u32 gu_ctl0;
	u32 gu_ctl1;
	u32 pcbr;
	u32 clock_gate_dis2;
	};

	/*
	* Save all Gunit registers that may be lost after a D3 and a subsequent
	* S0i[R123] transition. The list of registers needing a save/restore is
	* defined in the VLV2_S0IXRegs document. This documents marks all Gunit
	* registers in the following way:
	* - Driver: saved/restored by the driver
	* - Punit : saved/restored by the Punit firmware
	* - No, w/o marking: no need to save/restore, since the register is R/O or
	* used internally by the HW in a way that doesn't depend
	* keeping the content across a suspend/resume.
	* - Debug : used for debugging
	*
	* We save/restore all registers marked with 'Driver', with the following
	* exceptions:
	* - Registers out of use, including also registers marked with 'Debug'.
	* These have no effect on the driver's operation, so we don't save/restore
	* them to reduce the overhead.
	* - Registers that are fully setup by an initialization function called from
	* the resume path. For example many clock gating and RPS/RC6 registers.
	* - Registers that provide the right functionality with their reset defaults.
	*
	* TODO: Except for registers that based on the above 3 criteria can be safely
	* ignored, we save/restore all others, practically treating the HW context as
	* a black-box for the driver. Further investigation is needed to reduce the
	* saved/restored registers even further, by following the same 3 criteria.
	*/
	static void vlv_save_gunit_s0ix_state(struct drm_i915_private *i915)
	{
	struct vlv_s0ix_state *s = i915->vlv_s0ix_state;
	struct intel_uncore *uncore = &i915->uncore;
	int i;

	if (!s)
	return;

	/* GAM 0x4000-0x4770 */
	s->wr_watermark = intel_uncore_read(uncore, GEN7_WR_WATERMARK);
	s->gfx_prio_ctrl = intel_uncore_read(uncore, GEN7_GFX_PRIO_CTRL);
	s->arb_mode = intel_uncore_read(uncore, ARB_MODE);
	s->gfx_pend_tlb0 = intel_uncore_read(uncore, GEN7_GFX_PEND_TLB0);
	s->gfx_pend_tlb1 = intel_uncore_read(uncore, GEN7_GFX_PEND_TLB1);

	for (i = 0; i < ARRAY_SIZE(s->lra_limits); i++)
	s->lra_limits[i] = intel_uncore_read(uncore, GEN7_LRA_LIMITS(i));

	s->media_max_req_count = intel_uncore_read(uncore, GEN7_MEDIA_MAX_REQ_COUNT);
	s->gfx_max_req_count = intel_uncore_read(uncore, GEN7_GFX_MAX_REQ_COUNT);

	s->render_hwsp = intel_uncore_read(uncore, RENDER_HWS_PGA_GEN7);
	s->ecochk = intel_uncore_read(uncore, GAM_ECOCHK);
	s->bsd_hwsp = intel_uncore_read(uncore, BSD_HWS_PGA_GEN7);
	s->blt_hwsp = intel_uncore_read(uncore, BLT_HWS_PGA_GEN7);

	s->tlb_rd_addr = intel_uncore_read(uncore, GEN7_TLB_RD_ADDR);

	/* MBC 0x9024-0x91D0, 0x8500 */
	s->g3dctl = intel_uncore_read(uncore, VLV_G3DCTL);
	s->gsckgctl = intel_uncore_read(uncore, VLV_GSCKGCTL);
	s->mbctl = intel_uncore_read(uncore, GEN6_MBCTL);

	/* GCP 0x9400-0x9424, 0x8100-0x810C */
	s->ucgctl1 = intel_uncore_read(uncore, GEN6_UCGCTL1);
	s->ucgctl3 = intel_uncore_read(uncore, GEN6_UCGCTL3);
	s->rcgctl1 = intel_uncore_read(uncore, GEN6_RCGCTL1);
	s->rcgctl2 = intel_uncore_read(uncore, GEN6_RCGCTL2);
	s->rstctl = intel_uncore_read(uncore, GEN6_RSTCTL);
	s->misccpctl = intel_uncore_read(uncore, GEN7_MISCCPCTL);

	/* GPM 0xA000-0xAA84, 0x8000-0x80FC */
	s->gfxpause = intel_uncore_read(uncore, GEN6_GFXPAUSE);
	s->rpdeuhwtc = intel_uncore_read(uncore, GEN6_RPDEUHWTC);
	s->rpdeuc = intel_uncore_read(uncore, GEN6_RPDEUC);
	s->ecobus = intel_uncore_read(uncore, ECOBUS);
	s->pwrdwnupctl = intel_uncore_read(uncore, VLV_PWRDWNUPCTL);
	s->rp_down_timeout = intel_uncore_read(uncore, GEN6_RP_DOWN_TIMEOUT);
	s->rp_deucsw = intel_uncore_read(uncore, GEN6_RPDEUCSW);
	s->rcubmabdtmr = intel_uncore_read(uncore, GEN6_RCUBMABDTMR);
	s->rcedata = intel_uncore_read(uncore, VLV_RCEDATA);
	s->spare2gh = intel_uncore_read(uncore, VLV_SPAREG2H);

	/* Display CZ domain, 0x4400C-0x4402C, 0x4F000-0x4F11F */
	s->gt_imr = intel_uncore_read(uncore, GTIMR);
	s->gt_ier = intel_uncore_read(uncore, GTIER);
	s->pm_imr = intel_uncore_read(uncore, GEN6_PMIMR);
	s->pm_ier = intel_uncore_read(uncore, GEN6_PMIER);

	for (i = 0; i < ARRAY_SIZE(s->gt_scratch); i++)
	s->gt_scratch[i] = intel_uncore_read(uncore, GEN7_GT_SCRATCH(i));

	/* GT SA CZ domain, 0x100000-0x138124 */
	s->tilectl = intel_uncore_read(uncore, TILECTL);
	s->gt_fifoctl = intel_uncore_read(uncore, GTFIFOCTL);
	s->gtlc_wake_ctrl = intel_uncore_read(uncore, VLV_GTLC_WAKE_CTRL);
	s->gtlc_survive = intel_uncore_read(uncore, VLV_GTLC_SURVIVABILITY_REG);
	s->pmwgicz = intel_uncore_read(uncore, VLV_PMWGICZ);

	/* Gunit-Display CZ domain, 0x182028-0x1821CF */
	s->gu_ctl0 = intel_uncore_read(uncore, VLV_GU_CTL0);
	s->gu_ctl1 = intel_uncore_read(uncore, VLV_GU_CTL1);
	s->pcbr = intel_uncore_read(uncore, VLV_PCBR);
	s->clock_gate_dis2 = intel_uncore_read(uncore, VLV_GUNIT_CLOCK_GATE2);

	/*
	* Not saving any of:
	* DFT, 0x9800-0x9EC0
	* SARB, 0xB000-0xB1FC
	* GAC, 0x5208-0x524C, 0x14000-0x14C000
	* PCI CFG
	*/
	}

	static void vlv_restore_gunit_s0ix_state(struct drm_i915_private *i915)
	{
	struct vlv_s0ix_state *s = i915->vlv_s0ix_state;
	struct intel_uncore *uncore = &i915->uncore;
	int i;

	if (!s)
	return;

	/* GAM 0x4000-0x4770 */
	intel_uncore_write(uncore, GEN7_WR_WATERMARK, s->wr_watermark);
	intel_uncore_write(uncore, GEN7_GFX_PRIO_CTRL, s->gfx_prio_ctrl);
	intel_uncore_write(uncore, ARB_MODE, s->arb_mode \| (0xffff << 16));
	intel_uncore_write(uncore, GEN7_GFX_PEND_TLB0, s->gfx_pend_tlb0);
	intel_uncore_write(uncore, GEN7_GFX_PEND_TLB1, s->gfx_pend_tlb1);

	for (i = 0; i < ARRAY_SIZE(s->lra_limits); i++)
	intel_uncore_write(uncore, GEN7_LRA_LIMITS(i), s->lra_limits[i]);

	intel_uncore_write(uncore, GEN7_MEDIA_MAX_REQ_COUNT, s->media_max_req_count);
	intel_uncore_write(uncore, GEN7_GFX_MAX_REQ_COUNT, s->gfx_max_req_count);

	intel_uncore_write(uncore, RENDER_HWS_PGA_GEN7, s->render_hwsp);
	intel_uncore_write(uncore, GAM_ECOCHK, s->ecochk);
	intel_uncore_write(uncore, BSD_HWS_PGA_GEN7, s->bsd_hwsp);
	intel_uncore_write(uncore, BLT_HWS_PGA_GEN7, s->blt_hwsp);

	intel_uncore_write(uncore, GEN7_TLB_RD_ADDR, s->tlb_rd_addr);

	/* MBC 0x9024-0x91D0, 0x8500 */
	intel_uncore_write(uncore, VLV_G3DCTL, s->g3dctl);
	intel_uncore_write(uncore, VLV_GSCKGCTL, s->gsckgctl);
	intel_uncore_write(uncore, GEN6_MBCTL, s->mbctl);

	/* GCP 0x9400-0x9424, 0x8100-0x810C */
	intel_uncore_write(uncore, GEN6_UCGCTL1, s->ucgctl1);
	intel_uncore_write(uncore, GEN6_UCGCTL3, s->ucgctl3);
	intel_uncore_write(uncore, GEN6_RCGCTL1, s->rcgctl1);
	intel_uncore_write(uncore, GEN6_RCGCTL2, s->rcgctl2);
	intel_uncore_write(uncore, GEN6_RSTCTL, s->rstctl);
	intel_uncore_write(uncore, GEN7_MISCCPCTL, s->misccpctl);

	/* GPM 0xA000-0xAA84, 0x8000-0x80FC */
	intel_uncore_write(uncore, GEN6_GFXPAUSE, s->gfxpause);
	intel_uncore_write(uncore, GEN6_RPDEUHWTC, s->rpdeuhwtc);
	intel_uncore_write(uncore, GEN6_RPDEUC, s->rpdeuc);
	intel_uncore_write(uncore, ECOBUS, s->ecobus);
	intel_uncore_write(uncore, VLV_PWRDWNUPCTL, s->pwrdwnupctl);
	intel_uncore_write(uncore, GEN6_RP_DOWN_TIMEOUT, s->rp_down_timeout);
	intel_uncore_write(uncore, GEN6_RPDEUCSW, s->rp_deucsw);
	intel_uncore_write(uncore, GEN6_RCUBMABDTMR, s->rcubmabdtmr);
	intel_uncore_write(uncore, VLV_RCEDATA, s->rcedata);
	intel_uncore_write(uncore, VLV_SPAREG2H, s->spare2gh);

	/* Display CZ domain, 0x4400C-0x4402C, 0x4F000-0x4F11F */
	intel_uncore_write(uncore, GTIMR, s->gt_imr);
	intel_uncore_write(uncore, GTIER, s->gt_ier);
	intel_uncore_write(uncore, GEN6_PMIMR, s->pm_imr);
	intel_uncore_write(uncore, GEN6_PMIER, s->pm_ier);

	for (i = 0; i < ARRAY_SIZE(s->gt_scratch); i++)
	intel_uncore_write(uncore, GEN7_GT_SCRATCH(i), s->gt_scratch[i]);

	/* GT SA CZ domain, 0x100000-0x138124 */
	intel_uncore_write(uncore, TILECTL, s->tilectl);
	intel_uncore_write(uncore, GTFIFOCTL, s->gt_fifoctl);
	/*
	* Preserve the GT allow wake and GFX force clock bit, they are not
	* be restored, as they are used to control the s0ix suspend/resume
	* sequence by the caller.
	*/
	intel_uncore_rmw(uncore, VLV_GTLC_WAKE_CTRL, ~VLV_GTLC_ALLOWWAKEREQ,
	s->gtlc_wake_ctrl & ~VLV_GTLC_ALLOWWAKEREQ);

	intel_uncore_rmw(uncore, VLV_GTLC_SURVIVABILITY_REG, ~VLV_GFX_CLK_FORCE_ON_BIT,
	s->gtlc_survive & ~VLV_GFX_CLK_FORCE_ON_BIT);

	intel_uncore_write(uncore, VLV_PMWGICZ, s->pmwgicz);

	/* Gunit-Display CZ domain, 0x182028-0x1821CF */
	intel_uncore_write(uncore, VLV_GU_CTL0, s->gu_ctl0);
	intel_uncore_write(uncore, VLV_GU_CTL1, s->gu_ctl1);
	intel_uncore_write(uncore, VLV_PCBR, s->pcbr);
	intel_uncore_write(uncore, VLV_GUNIT_CLOCK_GATE2, s->clock_gate_dis2);
	}

	static int vlv_wait_for_pw_status(struct drm_i915_private *i915,
	u32 mask, u32 val)
	{
	i915_reg_t reg = VLV_GTLC_PW_STATUS;
	u32 reg_value;
	int ret;

	/* The HW does not like us polling for PW_STATUS frequently, so
	* use the sleeping loop rather than risk the busy spin within
	* intel_wait_for_register().
	*
	* Transitioning between RC6 states should be at most 2ms (see
	* valleyview_enable_rps) so use a 3ms timeout.
	*/
	ret = wait_for(((reg_value =
	intel_uncore_read_notrace(&i915->uncore, reg)) & mask)
	== val, 3);

	/* just trace the final value */
	trace_i915_reg_rw(false, reg, reg_value, sizeof(reg_value), true);

	return ret;
	}

	static int vlv_force_gfx_clock(struct drm_i915_private *i915, bool force_on)
	{
	struct intel_uncore *uncore = &i915->uncore;
	int err;

	intel_uncore_rmw(uncore, VLV_GTLC_SURVIVABILITY_REG, VLV_GFX_CLK_FORCE_ON_BIT,
	force_on ? VLV_GFX_CLK_FORCE_ON_BIT : 0);

	if (!force_on)
	return 0;

	err = intel_wait_for_register(uncore,
	VLV_GTLC_SURVIVABILITY_REG,
	VLV_GFX_CLK_STATUS_BIT,
	VLV_GFX_CLK_STATUS_BIT,
	20);
	if (err)
	drm_err(&i915->drm,
	"timeout waiting for GFX clock force-on (%08x)\n",
	intel_uncore_read(uncore, VLV_GTLC_SURVIVABILITY_REG));

	return err;
	}

	static int vlv_allow_gt_wake(struct drm_i915_private *i915, bool allow)
	{
	struct intel_uncore *uncore = &i915->uncore;
	u32 mask;
	u32 val;
	int err;

	intel_uncore_rmw(uncore, VLV_GTLC_WAKE_CTRL, VLV_GTLC_ALLOWWAKEREQ,
	allow ? VLV_GTLC_ALLOWWAKEREQ : 0);
	intel_uncore_posting_read(uncore, VLV_GTLC_WAKE_CTRL);

	mask = VLV_GTLC_ALLOWWAKEACK;
	val = allow ? mask : 0;

	err = vlv_wait_for_pw_status(i915, mask, val);
	if (err)
	drm_err(&i915->drm, "timeout disabling GT waking\n");

	return err;
	}

	static void vlv_wait_for_gt_wells(struct drm_i915_private *dev_priv,
	bool wait_for_on)
	{
	u32 mask;
	u32 val;

	mask = VLV_GTLC_PW_MEDIA_STATUS_MASK \| VLV_GTLC_PW_RENDER_STATUS_MASK;
	val = wait_for_on ? mask : 0;

	/*
	* RC6 transitioning can be delayed up to 2 msec (see
	* valleyview_enable_rps), use 3 msec for safety.
	*
	* This can fail to turn off the rc6 if the GPU is stuck after a failed
	* reset and we are trying to force the machine to sleep.
	*/
	if (vlv_wait_for_pw_status(dev_priv, mask, val))
	drm_dbg(&dev_priv->drm,
	"timeout waiting for GT wells to go %s\n",
	str_on_off(wait_for_on));
	}

	static void vlv_check_no_gt_access(struct drm_i915_private *i915)
	{
	struct intel_uncore *uncore = &i915->uncore;

	if (!(intel_uncore_read(uncore, VLV_GTLC_PW_STATUS) & VLV_GTLC_ALLOWWAKEERR))
	return;

	drm_dbg(&i915->drm, "GT register access while GT waking disabled\n");
	intel_uncore_write(uncore, VLV_GTLC_PW_STATUS, VLV_GTLC_ALLOWWAKEERR);
	}

	int vlv_suspend_complete(struct drm_i915_private *dev_priv)
	{
	u32 mask;
	int err;

	if (!IS_VALLEYVIEW(dev_priv) && !IS_CHERRYVIEW(dev_priv))
	return 0;

	/*
	* Bspec defines the following GT well on flags as debug only, so
	* don't treat them as hard failures.
	*/
	vlv_wait_for_gt_wells(dev_priv, false);

	mask = VLV_GTLC_RENDER_CTX_EXISTS \| VLV_GTLC_MEDIA_CTX_EXISTS;
	drm_WARN_ON(&dev_priv->drm,
	(intel_uncore_read(&dev_priv->uncore, VLV_GTLC_WAKE_CTRL) & mask) != mask);

	vlv_check_no_gt_access(dev_priv);

	err = vlv_force_gfx_clock(dev_priv, true);
	if (err)
	goto err1;

	err = vlv_allow_gt_wake(dev_priv, false);
	if (err)
	goto err2;

	vlv_save_gunit_s0ix_state(dev_priv);

	err = vlv_force_gfx_clock(dev_priv, false);
	if (err)
	goto err2;

	return 0;

	err2:
	/* For safety always re-enable waking and disable gfx clock forcing */
	vlv_allow_gt_wake(dev_priv, true);
	err1:
	vlv_force_gfx_clock(dev_priv, false);

	return err;
	}

	int vlv_resume_prepare(struct drm_i915_private *dev_priv, bool rpm_resume)
	{
	int err;
	int ret;

	if (!IS_VALLEYVIEW(dev_priv) && !IS_CHERRYVIEW(dev_priv))
	return 0;

	/*
	* If any of the steps fail just try to continue, that's the best we
	* can do at this point. Return the first error code (which will also
	* leave RPM permanently disabled).
	*/
	ret = vlv_force_gfx_clock(dev_priv, true);

	vlv_restore_gunit_s0ix_state(dev_priv);

	err = vlv_allow_gt_wake(dev_priv, true);
	if (!ret)
	ret = err;

	err = vlv_force_gfx_clock(dev_priv, false);
	if (!ret)
	ret = err;

	vlv_check_no_gt_access(dev_priv);

	if (rpm_resume)
	intel_init_clock_gating(dev_priv);

	return ret;
	}

	int vlv_suspend_init(struct drm_i915_private *i915)
	{
	if (!IS_VALLEYVIEW(i915))
	return 0;

	/* we write all the values in the struct, so no need to zero it out */
	i915->vlv_s0ix_state = kmalloc(sizeof(*i915->vlv_s0ix_state),
	GFP_KERNEL);
	if (!i915->vlv_s0ix_state)
	return -ENOMEM;

	return 0;
	}

	void vlv_suspend_cleanup(struct drm_i915_private *i915)
	{
	if (!i915->vlv_s0ix_state)
	return;

	kfree(i915->vlv_s0ix_state);
	i915->vlv_s0ix_state = NULL;
	}