[PATCH 2/2] mmc: sdhci-pci-gli: Disable ASPM during a suspension
From: Victor Ding <hidden>
Date: 2021-01-12 04:03:49
Also in:
linux-pci, lkml
Subsystem:
multimedia card (mmc), secure digital (sd) and sdio subsystem, secure digital host controller interface (sdhci) driver, the rest · Maintainers:
Ulf Hansson, Adrian Hunter, Linus Torvalds
GL9750 has a 3100us PortTPowerOnTime; however, it enters L1.2 after only ~4us inactivity per PCIe trace. During a suspend/resume process, PCI access operations are frequently longer than 4us apart. Therefore, the device frequently enters and leaves L1.2 during this process, causing longer than desirable suspend/resume time. The total time cost due to this L1.2 exit latency could add up to ~200ms. Considering that PCI access operations are fairly close to each other (though sometimes > 4us), the actual time the device could stay in L1.2 is negligible. Therefore, the little power-saving benefit from ASPM during suspend/resume does not overweight the performance degradation caused by long L1.2 exit latency. Therefore, this patch proposes to disable ASPM during a suspend/resume process. Signed-off-by: Victor Ding <redacted> --- drivers/mmc/host/sdhci-pci-core.c | 2 +- drivers/mmc/host/sdhci-pci-gli.c | 46 +++++++++++++++++++++++++++++-- drivers/mmc/host/sdhci-pci.h | 1 + 3 files changed, 46 insertions(+), 3 deletions(-)
diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
index 9552708846ca..fd7544a498c0 100644
--- a/drivers/mmc/host/sdhci-pci-core.c
+++ b/drivers/mmc/host/sdhci-pci-core.c@@ -67,7 +67,7 @@ static int sdhci_pci_init_wakeup(struct sdhci_pci_chip *chip) return 0; } -static int sdhci_pci_suspend_host(struct sdhci_pci_chip *chip) +int sdhci_pci_suspend_host(struct sdhci_pci_chip *chip) { int i, ret;
diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
index 9887485a4134..c7b788b0e22e 100644
--- a/drivers/mmc/host/sdhci-pci-gli.c
+++ b/drivers/mmc/host/sdhci-pci-gli.c@@ -109,6 +109,12 @@ #define GLI_MAX_TUNING_LOOP 40 +#ifdef CONFIG_PM_SLEEP +struct gli_host { + u16 linkctl_saved; +}; +#endif + /* Genesys Logic chipset */ static inline void gl9750_wt_on(struct sdhci_host *host) {
@@ -577,14 +583,48 @@ static u32 sdhci_gl9750_readl(struct sdhci_host *host, int reg) } #ifdef CONFIG_PM_SLEEP +static int sdhci_pci_gli_suspend(struct sdhci_pci_chip *chip) +{ + int ret; + struct sdhci_pci_slot *slot = chip->slots[0]; + struct pci_dev *pdev = slot->chip->pdev; + struct gli_host *gli_host = sdhci_pci_priv(slot); + + ret = pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, + &gli_host->linkctl_saved); + if (ret) + goto exit; + + ret = pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, + gli_host->linkctl_saved & ~PCI_EXP_LNKCTL_ASPMC); + if (ret) + goto exit; + + ret = sdhci_pci_suspend_host(chip); + +exit: + return ret; +} + static int sdhci_pci_gli_resume(struct sdhci_pci_chip *chip) { + int ret; struct sdhci_pci_slot *slot = chip->slots[0]; + struct pci_dev *pdev = slot->chip->pdev; + struct gli_host *gli_host = sdhci_pci_priv(slot); - pci_free_irq_vectors(slot->chip->pdev); + pci_free_irq_vectors(pdev); gli_pcie_enable_msi(slot); - return sdhci_pci_resume_host(chip); + ret = sdhci_pci_resume_host(chip); + if (ret) + goto exit; + + ret = pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL, + PCI_EXP_LNKCTL_ASPMC, gli_host->linkctl_saved); + +exit: + return ret; } static int sdhci_cqhci_gli_resume(struct sdhci_pci_chip *chip)
@@ -834,7 +874,9 @@ const struct sdhci_pci_fixes sdhci_gl9750 = { .probe_slot = gli_probe_slot_gl9750, .ops = &sdhci_gl9750_ops, #ifdef CONFIG_PM_SLEEP + .suspend = sdhci_pci_gli_suspend, .resume = sdhci_pci_gli_resume, + .priv_size = sizeof(struct gli_host), #endif };
diff --git a/drivers/mmc/host/sdhci-pci.h b/drivers/mmc/host/sdhci-pci.h
index d0ed232af0eb..16187a265e63 100644
--- a/drivers/mmc/host/sdhci-pci.h
+++ b/drivers/mmc/host/sdhci-pci.h@@ -187,6 +187,7 @@ static inline void *sdhci_pci_priv(struct sdhci_pci_slot *slot) } #ifdef CONFIG_PM_SLEEP +int sdhci_pci_suspend_host(struct sdhci_pci_chip *chip); int sdhci_pci_resume_host(struct sdhci_pci_chip *chip); #endif int sdhci_pci_enable_dma(struct sdhci_host *host);
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2.30.0.284.gd98b1dd5eaa7-goog