[PATCH 3/3] mmc: sdhci-pci-gli: Add a switch to enable/disable SSC for GL9750 and GL9755

From: Ben Chuang
Date: Wed Jan 19 2022 - 02:55:32 EST


From: Ben Chuang <ben.chuang@xxxxxxxxxxxxxxxxxxx>

Add a vendor-specific bit at the bit26 of GL9750's register 878h and
GL9755's register 78h to decide whether to disable SSC function. If
this bit is set, the SSC function will be disabled.

Signed-off-by: Ben Chuang <ben.chuang@xxxxxxxxxxxxxxxxxxx>
---
drivers/mmc/host/sdhci-pci-gli.c | 66 ++++++++++++++++++++++++++------
1 file changed, 54 insertions(+), 12 deletions(-)

diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
index 9de3d91283af..b8cd7a365ec2 100644
--- a/drivers/mmc/host/sdhci-pci-gli.c
+++ b/drivers/mmc/host/sdhci-pci-gli.c
@@ -62,6 +62,7 @@
#define GLI_9750_MISC_RX_INV_OFF 0x0
#define GLI_9750_MISC_RX_INV_VALUE GLI_9750_MISC_RX_INV_OFF
#define GLI_9750_MISC_TX1_DLY_VALUE 0x5
+#define SDHCI_GLI_9750_MISC_SSC_OFF BIT(26)

#define SDHCI_GLI_9750_TUNING_CONTROL 0x540
#define SDHCI_GLI_9750_TUNING_CONTROL_EN BIT(4)
@@ -134,6 +135,9 @@
#define PCI_GLI_9755_SerDes 0x70
#define PCI_GLI_9755_SCP_DIS BIT(19)

+#define PCI_GLI_9755_MISC 0x78
+#define PCI_GLI_9755_MISC_SSC_OFF BIT(26)
+
#define GLI_MAX_TUNING_LOOP 40

/* Genesys Logic chipset */
@@ -368,6 +372,19 @@ static void gl9750_set_pll(struct sdhci_host *host, u8 dir, u16 ldiv, u8 pdiv)
mdelay(1);
}

+static bool gl9750_ssc_enable(struct sdhci_host *host)
+{
+ u32 misc;
+ u8 off;
+
+ gl9750_wt_on(host);
+ misc = sdhci_readl(host, SDHCI_GLI_9750_MISC);
+ off = FIELD_GET(SDHCI_GLI_9750_MISC_SSC_OFF, misc);
+ gl9750_wt_off(host);
+
+ return !off;
+}
+
static void gl9750_set_ssc(struct sdhci_host *host, u8 enable, u8 step, u16 ppm)
{
u32 pll;
@@ -389,22 +406,28 @@ static void gl9750_set_ssc(struct sdhci_host *host, u8 enable, u8 step, u16 ppm)

static void gl9750_set_ssc_pll_205mhz(struct sdhci_host *host)
{
- /* set pll to 205MHz and enable ssc */
- gl9750_set_ssc(host, 0x1, 0xF, 0x5A1D);
+ bool enable = gl9750_ssc_enable(host);
+
+ /* set pll to 205MHz and ssc */
+ gl9750_set_ssc(host, enable, 0xF, 0x5A1D);
gl9750_set_pll(host, 0x1, 0x246, 0x0);
}

static void gl9750_set_ssc_pll_100mhz(struct sdhci_host *host)
{
- /* set pll to 100MHz and enable ssc */
- gl9750_set_ssc(host, 0x1, 0xE, 0x51EC);
+ bool enable = gl9750_ssc_enable(host);
+
+ /* set pll to 100MHz and ssc */
+ gl9750_set_ssc(host, enable, 0xE, 0x51EC);
gl9750_set_pll(host, 0x1, 0x244, 0x1);
}

static void gl9750_set_ssc_pll_50mhz(struct sdhci_host *host)
{
- /* set pll to 50MHz and enable ssc */
- gl9750_set_ssc(host, 0x1, 0xE, 0x51EC);
+ bool enable = gl9750_ssc_enable(host);
+
+ /* set pll to 50MHz and ssc */
+ gl9750_set_ssc(host, enable, 0xE, 0x51EC);
gl9750_set_pll(host, 0x1, 0x244, 0x3);
}

@@ -529,6 +552,19 @@ static void gl9755_set_pll(struct pci_dev *pdev, u8 dir, u16 ldiv, u8 pdiv)
mdelay(1);
}

+static bool gl9755_ssc_enable(struct pci_dev *pdev)
+{
+ u32 misc;
+ u8 off;
+
+ gl9755_wt_on(pdev);
+ pci_read_config_dword(pdev, PCI_GLI_9755_MISC, &misc);
+ off = FIELD_GET(PCI_GLI_9755_MISC_SSC_OFF, misc);
+ gl9755_wt_off(pdev);
+
+ return !off;
+}
+
static void gl9755_set_ssc(struct pci_dev *pdev, u8 enable, u8 step, u16 ppm)
{
u32 pll;
@@ -550,22 +586,28 @@ static void gl9755_set_ssc(struct pci_dev *pdev, u8 enable, u8 step, u16 ppm)

static void gl9755_set_ssc_pll_205mhz(struct pci_dev *pdev)
{
- /* set pll to 205MHz and enable ssc */
- gl9755_set_ssc(pdev, 0x1, 0xF, 0x5A1D);
+ bool enable = gl9755_ssc_enable(pdev);
+
+ /* set pll to 205MHz and ssc */
+ gl9755_set_ssc(pdev, enable, 0xF, 0x5A1D);
gl9755_set_pll(pdev, 0x1, 0x246, 0x0);
}

static void gl9755_set_ssc_pll_100mhz(struct pci_dev *pdev)
{
- /* set pll to 100MHz and enable ssc */
- gl9755_set_ssc(pdev, 0x1, 0xE, 0x51EC);
+ bool enable = gl9755_ssc_enable(pdev);
+
+ /* set pll to 100MHz and ssc */
+ gl9755_set_ssc(pdev, enable, 0xE, 0x51EC);
gl9755_set_pll(pdev, 0x1, 0x244, 0x1);
}

static void gl9755_set_ssc_pll_50mhz(struct pci_dev *pdev)
{
- /* set pll to 50MHz and enable ssc */
- gl9755_set_ssc(pdev, 0x1, 0xE, 0x51EC);
+ bool enable = gl9755_ssc_enable(pdev);
+
+ /* set pll to 50MHz and ssc */
+ gl9755_set_ssc(pdev, enable, 0xE, 0x51EC);
gl9755_set_pll(pdev, 0x1, 0x244, 0x3);
}

--
2.34.1