Subject: [PATCH V7 3/3] mmc: sdhci-pci-o2micro: Fix O2 Host data read/write DLL Lock Phase shift issue

[Shirley Her (SC)]

Fix data read/write error in HS200 mode due to chip DLL lock phase shift

Signed-off-by:Shirley Her <shirley.her@xxxxxxxxxxxxxx>
---
change in V7:
 1. change subject
 2. change the sdhci_o2_wait_dll_detect_lock function
 3. add suitable usleep_range() to detect dll lock status

chagne in V6:
 1. define constant by using array size
 2. add more explanation for the code
 3. fix loop forever code error

change in V5:
 1. split 2 patches into 3 patches
 2. make dll_adjust_count start from 0
 3. fix ret overwritten issue
 4. use break instead of goto

change in V4:
 1. add a bug fix for V3

change in V3:
 1. add more explanation in dll_recovery and execute_tuning function
 2. move dll_adjust_count to O2_host struct
 3. fix some coding style error
 4. renaming O2_PLL_WDT_CONTROL1 TO O2_PLL_DLL_WDT_CONTROL1

change in V2:
 1. use usleep_range instead of udelay
 2. move dll_adjust_count to sdhci-pci-o2micro.c

chagne in V1:
 1. add error recovery function to relock DLL with correct phase
 2. retuning HS200 after DLL locked
---
 drivers/mmc/host/sdhci-pci-o2micro.c | 125 ++++++++++++++++++++++++++++++++++-
 1 file changed, 123 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-pci-o2micro.c b/drivers/mmc/host/sdhci-pci-o2micro.c
index 021e481..f0b3d93 100644
--- a/drivers/mmc/host/sdhci-pci-o2micro.c
+++ b/drivers/mmc/host/sdhci-pci-o2micro.c
@@ -11,6 +11,7 @@
 #include <linux/mmc/host.h>
 #include <linux/mmc/mmc.h>
 #include <linux/delay.h>
+#include <linux/iopoll.h>
 
 #include "sdhci.h"
 #include "sdhci-pci.h"
@@ -55,9 +56,18 @@
 #define  O2_PLL_FORCE_ACTIVE	BIT(18)
 #define  O2_PLL_LOCK_STATUS	BIT(14)
 #define  O2_PLL_SOFT_RESET	BIT(12)
+#define  O2_DLL_LOCK_STATUS	BIT(11)
 
 #define O2_SD_DETECT_SETTING 0x324
 
+static const u32 dmdn_table[] = {0x2B1C0000,
+	0x2C1A0000, 0x371B0000, 0x35100000};
+#define DMDN_SZ ARRAY_SIZE(dmdn_table)
+
+struct o2_host {
+	u8 dll_adjust_count;
+};
+
 static void sdhci_o2_wait_card_detect_stable(struct sdhci_host *host)
 {
 	ktime_t timeout;
@@ -133,7 +143,8 @@ static int sdhci_o2_get_cd(struct mmc_host *mmc)
 {
 	struct sdhci_host *host = mmc_priv(mmc);
 
-	sdhci_o2_enable_internal_clock(host);
+	if (!(sdhci_readw(host, O2_PLL_DLL_WDT_CONTROL1) & O2_PLL_LOCK_STATUS))
+		sdhci_o2_enable_internal_clock(host);
 
 	return !!(sdhci_readl(host, SDHCI_PRESENT_STATE) & SDHCI_CARD_PRESENT);
 }
@@ -141,6 +152,7 @@ static int sdhci_o2_get_cd(struct mmc_host *mmc)
 static void o2_pci_set_baseclk(struct sdhci_pci_chip *chip, u32 value)
 {
 	u32 scratch_32;
+
 	pci_read_config_dword(chip->pdev,
 			      O2_SD_PLL_SETTING, &scratch_32);
 
@@ -151,6 +163,25 @@ static void o2_pci_set_baseclk(struct sdhci_pci_chip *chip, u32 value)
 			       O2_SD_PLL_SETTING, scratch_32);
 }
 
+static u32 sdhci_o2_pll_dll_wdt_control(struct sdhci_host *host)
+{
+	return sdhci_readl(host, O2_PLL_DLL_WDT_CONTROL1);
+}
+
+/*
+ * This function is used to detect dll lock status.
+ * Since the dll lock status bit will toggle randomly
+ * with very short interval which needs to be polled
+ * as fast as possible. Set sleep_us as 1 microsecond.
+ */
+static int sdhci_o2_wait_dll_detect_lock(struct sdhci_host *host)
+{
+	u32	scratch32 = 0;
+
+	return readx_poll_timeout(sdhci_o2_pll_dll_wdt_control, host,
+		scratch32, !(scratch32 & O2_DLL_LOCK_STATUS), 1, 1000000);
+}
+
 static void sdhci_o2_set_tuning_mode(struct sdhci_host *host)
 {
 	u16 reg;
@@ -188,6 +219,83 @@ static void __sdhci_o2_execute_tuning(struct sdhci_host *host, u32 opcode)
 	sdhci_reset_tuning(host);
 }
 
+/*
+ * This function is used to fix o2 dll shift issue.
+ * It isn't necessary to detect card present before recovery.
+ * Firstly, it is used by bht emmc card, which is embedded.
+ * Second, before call recovery card present will be detected
+ * outside of the execute tuning function.
+ */
+static int sdhci_o2_dll_recovery(struct sdhci_host *host)
+{
+	int ret = 0;
+	u8 scratch_8 = 0;
+	u32 scratch_32 = 0;
+	struct sdhci_pci_slot *slot = sdhci_priv(host);
+	struct sdhci_pci_chip *chip = slot->chip;
+	struct o2_host *o2_host = sdhci_pci_priv(slot);
+
+	/* UnLock WP */
+	pci_read_config_byte(chip->pdev,
+			O2_SD_LOCK_WP, &scratch_8);
+	scratch_8 &= 0x7f;
+	pci_write_config_byte(chip->pdev, O2_SD_LOCK_WP, scratch_8);
+	while (o2_host->dll_adjust_count < DMDN_SZ && !ret) {
+		/* Disable clock */
+		sdhci_writeb(host, 0, SDHCI_CLOCK_CONTROL);
+
+		/* PLL software reset */
+		scratch_32 = sdhci_readl(host, O2_PLL_DLL_WDT_CONTROL1);
+		scratch_32 |= O2_PLL_SOFT_RESET;
+		sdhci_writel(host, scratch_32, O2_PLL_DLL_WDT_CONTROL1);
+
+		pci_read_config_dword(chip->pdev,
+					    O2_SD_FUNC_REG4,
+					    &scratch_32);
+		/* Enable Base Clk setting change */
+		scratch_32 |= O2_SD_FREG4_ENABLE_CLK_SET;
+		pci_write_config_dword(chip->pdev, O2_SD_FUNC_REG4, scratch_32);
+		o2_pci_set_baseclk(chip, dmdn_table[o2_host->dll_adjust_count]);
+
+		/* Enable internal clock */
+		scratch_8 = SDHCI_CLOCK_INT_EN;
+		sdhci_writeb(host, scratch_8, SDHCI_CLOCK_CONTROL);
+
+		if (sdhci_o2_get_cd(host->mmc)) {
+			/*
+			 * need wait at least 5ms for dll status stable,
+			 * after enable internal clock
+			 */
+			usleep_range(5000, 6000);
+			if (sdhci_o2_wait_dll_detect_lock(host)) {
+				scratch_8 |= SDHCI_CLOCK_CARD_EN;
+				sdhci_writeb(host, scratch_8,
+					SDHCI_CLOCK_CONTROL);
+				ret = 1;
+			} else {
+				pr_warn("%s: DLL unlocked when dll_adjust_count is %d.\n",
+					mmc_hostname(host->mmc),
+					o2_host->dll_adjust_count);
+			}
+		} else {
+			pr_err("%s: card present detect failed.\n",
+				mmc_hostname(host->mmc));
+			break;
+		}
+
+		o2_host->dll_adjust_count++;
+	}
+	if (!ret && o2_host->dll_adjust_count == DMDN_SZ)
+		pr_err("%s: DLL adjust over max times\n",
+		mmc_hostname(host->mmc));
+	/* Lock WP */
+	pci_read_config_byte(chip->pdev,
+				   O2_SD_LOCK_WP, &scratch_8);
+	scratch_8 |= 0x80;
+	pci_write_config_byte(chip->pdev, O2_SD_LOCK_WP, scratch_8);
+	return ret;
+}
+
 static int sdhci_o2_execute_tuning(struct mmc_host *mmc, u32 opcode)
 {
 	struct sdhci_host *host = mmc_priv(mmc);
@@ -202,7 +310,16 @@ static int sdhci_o2_execute_tuning(struct mmc_host *mmc, u32 opcode)
 
 	if (WARN_ON(opcode != MMC_SEND_TUNING_BLOCK_HS200))
 		return -EINVAL;
-
+	/*
+	 * Judge the tuning reason, whether caused by dll shift
+	 * If cause by dll shift, should call sdhci_o2_dll_recovery
+	 */
+	if (!sdhci_o2_wait_dll_detect_lock(host))
+		if (!sdhci_o2_dll_recovery(host)) {
+			pr_err("%s: o2 dll recovery failed\n",
+				mmc_hostname(host->mmc));
+			return -EINVAL;
+		}
 	/*
 	 * o2 sdhci host didn't support 8bit emmc tuning
 	 */
@@ -370,6 +487,7 @@ static void sdhci_o2_enable_clk(struct sdhci_host *host, u16 clk)
 	clk |= SDHCI_CLOCK_INT_EN;
 	sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
 
+	sdhci_o2_enable_internal_clock(host);
 	if (sdhci_o2_get_cd(host->mmc)) {
 		clk |= SDHCI_CLOCK_CARD_EN;
 		sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
@@ -395,12 +513,14 @@ int sdhci_pci_o2_probe_slot(struct sdhci_pci_slot *slot)
 {
 	struct sdhci_pci_chip *chip;
 	struct sdhci_host *host;
+	struct o2_host *o2_host = sdhci_pci_priv(slot);
 	u32 reg, caps;
 	int ret;
 
 	chip = slot->chip;
 	host = slot->host;
 
+	o2_host->dll_adjust_count = 0;	
 	caps = sdhci_readl(host, SDHCI_CAPABILITIES);
 
 	/*
@@ -687,4 +807,5 @@ const struct sdhci_pci_fixes sdhci_o2 = {
 	.resume = sdhci_pci_o2_resume,
 #endif
 	.ops = &sdhci_pci_o2_ops,
+	.priv_size = sizeof(struct o2_host),
 };
-- 
2.7.4