Commit 1202d617 authored by Sven van Ashbrook's avatar Sven van Ashbrook Committed by Ulf Hansson
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mmc: sdhci-pci-gli: fix LPM negotiation so x86/S0ix SoCs can suspend 



To improve the r/w performance of GL9763E, the current driver inhibits LPM
negotiation while the device is active.

This prevents a large number of SoCs from suspending, notably x86 systems
which commonly use S0ix as the suspend mechanism - for example, Intel
Alder Lake and Raptor Lake processors.

Failure description:
1. Userspace initiates s2idle suspend (e.g. via writing to
   /sys/power/state)
2. This switches the runtime_pm device state to active, which disables
   LPM negotiation, then calls the "regular" suspend callback
3. With LPM negotiation disabled, the bus cannot enter low-power state
4. On a large number of SoCs, if the bus not in a low-power state, S0ix
   cannot be entered, which in turn prevents the SoC from entering
   suspend.

Fix by re-enabling LPM negotiation in the device's suspend callback.

Suggested-by: default avatarStanislaw Kardach <skardach@google.com>
Fixes: f9e5b339 ("mmc: host: Improve I/O read/write performance for GL9763E")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarSven van Ashbrook <svenva@chromium.org>
Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20230831160055.v3.1.I7ed1ca09797be2dd76ca914c57d88b32d24dac88@changeid


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 32a9cdb8

drivers/mmc/host/sdhci-pci-gli.c

+66 −38
Original line number Diff line number Diff line
@@ -1144,42 +1144,6 @@ static u32 sdhci_gl9750_readl(struct sdhci_host *host, int reg) 
	return value;

}



#ifdef CONFIG_PM_SLEEP

static int sdhci_pci_gli_resume(struct sdhci_pci_chip *chip)

{

	struct sdhci_pci_slot *slot = chip->slots[0];



	pci_free_irq_vectors(slot->chip->pdev);

	gli_pcie_enable_msi(slot);



	return sdhci_pci_resume_host(chip);

}



static int sdhci_cqhci_gli_resume(struct sdhci_pci_chip *chip)

{

	struct sdhci_pci_slot *slot = chip->slots[0];

	int ret;



	ret = sdhci_pci_gli_resume(chip);

	if (ret)

		return ret;



	return cqhci_resume(slot->host->mmc);

}



static int sdhci_cqhci_gli_suspend(struct sdhci_pci_chip *chip)

{

	struct sdhci_pci_slot *slot = chip->slots[0];

	int ret;



	ret = cqhci_suspend(slot->host->mmc);

	if (ret)

		return ret;



	return sdhci_suspend_host(slot->host);

}

#endif



static void gl9763e_hs400_enhanced_strobe(struct mmc_host *mmc,

					  struct mmc_ios *ios)

{
@@ -1420,6 +1384,70 @@ static int gl9763e_runtime_resume(struct sdhci_pci_chip *chip) 
}

#endif



#ifdef CONFIG_PM_SLEEP

static int sdhci_pci_gli_resume(struct sdhci_pci_chip *chip)

{

	struct sdhci_pci_slot *slot = chip->slots[0];



	pci_free_irq_vectors(slot->chip->pdev);

	gli_pcie_enable_msi(slot);



	return sdhci_pci_resume_host(chip);

}



static int gl9763e_resume(struct sdhci_pci_chip *chip)

{

	struct sdhci_pci_slot *slot = chip->slots[0];

	int ret;



	ret = sdhci_pci_gli_resume(chip);

	if (ret)

		return ret;



	ret = cqhci_resume(slot->host->mmc);

	if (ret)

		return ret;



	/*

	 * Disable LPM negotiation to bring device back in sync

	 * with its runtime_pm state.

	 */

	gl9763e_set_low_power_negotiation(slot, false);



	return 0;

}



static int gl9763e_suspend(struct sdhci_pci_chip *chip)

{

	struct sdhci_pci_slot *slot = chip->slots[0];

	int ret;



	/*

	 * Certain SoCs can suspend only with the bus in low-

	 * power state, notably x86 SoCs when using S0ix.

	 * Re-enable LPM negotiation to allow entering L1 state

	 * and entering system suspend.

	 */

	gl9763e_set_low_power_negotiation(slot, true);



	ret = cqhci_suspend(slot->host->mmc);

	if (ret)

		goto err_suspend;



	ret = sdhci_suspend_host(slot->host);

	if (ret)

		goto err_suspend_host;



	return 0;



err_suspend_host:

	cqhci_resume(slot->host->mmc);

err_suspend:

	gl9763e_set_low_power_negotiation(slot, false);

	return ret;

}

#endif



static int gli_probe_slot_gl9763e(struct sdhci_pci_slot *slot)

{

	struct pci_dev *pdev = slot->chip->pdev;
@@ -1527,8 +1555,8 @@ const struct sdhci_pci_fixes sdhci_gl9763e = { 
	.probe_slot	= gli_probe_slot_gl9763e,

	.ops            = &sdhci_gl9763e_ops,

#ifdef CONFIG_PM_SLEEP

	.resume		= sdhci_cqhci_gli_resume,

	.suspend	= sdhci_cqhci_gli_suspend,

	.resume		= gl9763e_resume,

	.suspend	= gl9763e_suspend,

#endif

#ifdef CONFIG_PM

	.runtime_suspend = gl9763e_runtime_suspend,