Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Renius Chen <reniuschengl@gmail.com>
To:     ulf.hansson@linaro.org, adrian.hunter@intel.com
Cc:     linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
        Ben.Chuang@genesyslogic.com.tw,
        Renius Chen <reniuschengl@gmail.com>
Subject: [PATCH] mmc: sdhci-pci-gli: Improve Random 4K Read Performance of GL9763E
Date:   Thu, 24 Jun 2021 10:16:48 +0800
Message-Id: <20210624021648.101033-1-reniuschengl@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

During a sequence of random 4K read operations, the performance will be
reduced due to spending much time on entering/exiting the low power state
between requests. We disable the low power state negotiation of GL9763E
during a sequence of random 4K read operations to improve the performance
and enable it again after the operations have finished.

Signed-off-by: Renius Chen <reniuschengl@gmail.com>
---
 drivers/mmc/host/sdhci-pci-gli.c | 86 ++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
index 7ba0fd601696..26df8ec5d67c 100644
--- a/drivers/mmc/host/sdhci-pci-gli.c
+++ b/drivers/mmc/host/sdhci-pci-gli.c
@@ -88,6 +88,9 @@
 #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_MAX 0x3FF
@@ -691,6 +694,86 @@ static void sdhci_gl9763e_dumpregs(struct mmc_host *mmc)
 	sdhci_dumpregs(mmc_priv(mmc));
 }
 
+static void gl9763e_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+	struct sdhci_host *host = mmc_priv(mmc);
+	struct mmc_command *cmd;
+	struct sdhci_pci_slot *slot = sdhci_priv(host);
+	struct pci_dev *pdev = slot->chip->pdev;
+	u32 value;
+	static bool start_4k_r;
+	static int  continuous_4k_r;
+
+	cmd = (mrq->sbc && !(host->flags & SDHCI_AUTO_CMD23)) ? mrq->sbc : mrq->cmd;
+
+	if (cmd->opcode == MMC_READ_MULTIPLE_BLOCK) {
+		if (cmd->data->blocks == 8) {
+			continuous_4k_r++;
+
+			if ((!start_4k_r) && (continuous_4k_r >= 3)) {
+				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);
+				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);
+
+				start_4k_r = true;
+			}
+		} else {
+			continuous_4k_r = 0;
+
+			if (start_4k_r) {
+				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);
+				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);
+
+				start_4k_r = false;
+			}
+		}
+	} else {
+		continuous_4k_r = 0;
+
+		if (start_4k_r)	{
+			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);
+			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);
+
+			start_4k_r = false;
+		}
+	}
+
+	sdhci_request(mmc, mrq);
+}
+
+
 static void sdhci_gl9763e_cqe_pre_enable(struct mmc_host *mmc)
 {
 	struct cqhci_host *cq_host = mmc->cqe_private;
@@ -848,6 +931,9 @@ static int gli_probe_slot_gl9763e(struct sdhci_pci_slot *slot)
 	gli_pcie_enable_msi(slot);
 	host->mmc_host_ops.hs400_enhanced_strobe =
 					gl9763e_hs400_enhanced_strobe;
+
+	host->mmc_host_ops.request = gl9763e_request;
+
 	gli_set_gl9763e(slot);
 	sdhci_enable_v4_mode(host);
 
-- 
2.27.0