From: Jason Lai <jasonlai.genesyslogic@xxxxxxxxx> To improve READ/WRITE performance and take battery life into account, we turn on GL9763E L1 negotiation before entering runtime suspend and turn off GL9763E L1 negotiation while executing runtime resume. That is to say, GL9763E will not enter L1 state when executing I/O requests and enter L1 state when PCIe bus idle. Signed-off-by: Renius Chen <reniuschengl@xxxxxxxxx> Signed-off-by: Jason Lai <jason.lai@xxxxxxxxxxxxxxxxxxx> --- This patch is the follow-up to the patch [1] and adopt Ulf's comment. Due to flaws in hardware design, GL9763E takes long time to exit from L1 state. The I/O performance will suffer severe impact if it often enter and exit L1 state during I/O requests. [1] https://patchwork.kernel.org/project/linux-mmc/list/?series=646869 --- drivers/mmc/host/sdhci-pci-gli.c | 34 ++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c index d09728c37d03..69bc3d614e15 100644 --- a/drivers/mmc/host/sdhci-pci-gli.c +++ b/drivers/mmc/host/sdhci-pci-gli.c @@ -95,6 +95,9 @@ #define PCIE_GLI_9763E_SCR 0x8E0 #define GLI_9763E_SCR_AXI_REQ BIT(9) +#define PCIE_GLI_9763E_CFG 0x8A0 +#define GLI_9763E_CFG_LPSN_DIS BIT(12) + #define PCIE_GLI_9763E_CFG2 0x8A4 #define GLI_9763E_CFG2_L1DLY GENMASK(28, 19) #define GLI_9763E_CFG2_L1DLY_MID 0x54 @@ -818,6 +821,31 @@ static void sdhci_gl9763e_dumpregs(struct mmc_host *mmc) sdhci_dumpregs(mmc_priv(mmc)); } +static void gl9763e_set_low_power_negotiation(struct sdhci_pci_slot *slot, bool enable) +{ + struct pci_dev *pdev = slot->chip->pdev; + u32 value; + + pci_read_config_dword(pdev, PCIE_GLI_9763E_VHS, &value); + value &= ~GLI_9763E_VHS_REV; + value |= FIELD_PREP(GLI_9763E_VHS_REV, GLI_9763E_VHS_REV_W); + pci_write_config_dword(pdev, PCIE_GLI_9763E_VHS, value); + + pci_read_config_dword(pdev, PCIE_GLI_9763E_CFG, &value); + + if (enable) + value &= ~GLI_9763E_CFG_LPSN_DIS; + else + value |= GLI_9763E_CFG_LPSN_DIS; + + pci_write_config_dword(pdev, PCIE_GLI_9763E_CFG, value); + + pci_read_config_dword(pdev, PCIE_GLI_9763E_VHS, &value); + value &= ~GLI_9763E_VHS_REV; + value |= FIELD_PREP(GLI_9763E_VHS_REV, GLI_9763E_VHS_REV_R); + pci_write_config_dword(pdev, PCIE_GLI_9763E_VHS, value); +} + static void sdhci_gl9763e_cqe_pre_enable(struct mmc_host *mmc) { struct cqhci_host *cq_host = mmc->cqe_private; @@ -959,6 +987,9 @@ static int gl9763e_runtime_suspend(struct sdhci_pci_chip *chip) struct sdhci_host *host = slot->host; u16 clock; + /* Enable LPM negotiation to allow entering L1 state */ + gl9763e_set_low_power_negotiation(slot, true); + clock = sdhci_readw(host, SDHCI_CLOCK_CONTROL); clock &= ~(SDHCI_CLOCK_PLL_EN | SDHCI_CLOCK_CARD_EN); sdhci_writew(host, clock, SDHCI_CLOCK_CONTROL); @@ -989,6 +1020,9 @@ static int gl9763e_runtime_resume(struct sdhci_pci_chip *chip) clock |= SDHCI_CLOCK_CARD_EN; sdhci_writew(host, clock, SDHCI_CLOCK_CONTROL); + /* Disable LPM negotiation to avoid entering L1 state. */ + gl9763e_set_low_power_negotiation(slot, false); + return 0; } #endif -- 2.36.1
