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Commit 85411b7c authored by Ziqi Chen's avatar Ziqi Chen
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scsi: ufs: Fix ufs power down/on specs violation in suspend/resume path 



As per specs, while powering off/on the ufs device, RST_N signal and
REF_CLK signal should be between VSS(Ground) and VCCQ.

Commit a8bc450a ("scsi: ufs: fix ufs power down specs violation
in shutdown path") fixed this violation from shutdown path. But this
issue can still be observed during system suspend and system resume
if spm_lvl set to 5. This new change fixs it in suspend/resume path.

Power down:
1. Turn-off REF_CLK
2. Assert RST_N low
3. Turn-off VCCQ
4. Turn-off VCC.

power on:
1. Turn-on VCCQ
2. Turn-on VCC
3. Turn-On REF_CLK
4. Deassert RST_N high.

Change-Id: Ia2390021d563887a24eb10282fca70400f2ac1aa
Signed-off-by: default avatarZiqi Chen <ziqichen@codeaurora.org>
parent da2a0248

drivers/scsi/ufs/ufshcd.c

+21 −9
Original line number Diff line number Diff line
@@ -10428,8 +10428,8 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op) 
	 */

	ufshcd_disable_irq(hba);



	/* reset the connected UFS device during shutdown */

	if (ufshcd_is_shutdown_pm(pm_op)) {

	/* reset the connected UFS device during power down */

	if (ufshcd_is_link_off(hba)) {

		ret = ufshcd_assert_device_reset(hba);

		if (ret)

			goto set_link_active;
@@ -10469,6 +10469,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op) 
		ufshcd_set_link_active(hba);

	} else if (ufshcd_is_link_off(hba)) {

		ufshcd_update_error_stats(hba, UFS_ERR_VOPS_SUSPEND);

		ufshcd_deassert_device_reset(hba);

		ufshcd_host_reset_and_restore(hba);

	}

set_dev_active:
@@ -10511,17 +10512,25 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op) 
	old_pwr_mode = hba->curr_dev_pwr_mode;



	ufshcd_hba_vreg_set_hpm(hba);



	ret = ufshcd_vreg_set_hpm(hba);

	if (ret)

		goto out;



	/* Make sure clocks are enabled before accessing controller */

	ret = ufshcd_enable_clocks(hba);

	if (ret)

		goto out;

		goto disable_vreg;



	/* enable the host irq as host controller would be active soon */

	ufshcd_enable_irq(hba);



	ret = ufshcd_vreg_set_hpm(hba);

	/* Pull up RST_n before device reset */

	if (ufshcd_is_link_off(hba)) {

		ret = ufshcd_deassert_device_reset(hba);

		if (ret)

			goto disable_irq_and_vops_clks;

	}



	/*

	 * Call vendor specific resume callback. As these callbacks may access
@@ -10530,7 +10539,7 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op) 
	 */

	ret = ufshcd_vops_resume(hba, pm_op);

	if (ret)

		goto disable_vreg;

		goto assert_device_reset;



	if (ufshcd_is_link_hibern8(hba)) {

		ret = ufshcd_uic_hibern8_exit(hba);
@@ -10621,8 +10630,9 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op) 
		hba->hibern8_on_idle.state = HIBERN8_ENTERED;

vendor_suspend:

	ufshcd_vops_suspend(hba, pm_op);

disable_vreg:

	ufshcd_vreg_set_lpm(hba);

assert_device_reset:

	if (ufshcd_is_link_off(hba))

		ufshcd_assert_device_reset(hba);

disable_irq_and_vops_clks:

	ufshcd_disable_irq(hba);

	if (hba->clk_scaling.is_allowed)
@@ -10630,6 +10640,8 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op) 
	ufshcd_disable_clocks(hba, false);

	if (ufshcd_is_clkgating_allowed(hba))

		hba->clk_gating.state = CLKS_OFF;

disable_vreg:

	ufshcd_vreg_set_lpm(hba);

out:

	hba->pm_op_in_progress = 0;