[PATCH 4.9 6/7] mmc: rtsx: add 74 Clocks in power on flow

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Ricky WU <ricky_wu@realtek.com>

commit 1f311c94aabdb419c28e3147bcc8ab89269f1a7e upstream.

SD spec definition:
"Host provides at least 74 Clocks before issuing first command"
After 1ms for the voltage stable then start issuing the Clock signals

if POWER STATE is
MMC_POWER_OFF to MMC_POWER_UP to issue Clock signal to card
MMC_POWER_UP to MMC_POWER_ON to stop issuing signal to card

Signed-off-by: Ricky Wu <ricky_wu@realtek.com>
Link: https://lore.kernel.org/r/1badf10aba764191a1a752edcbf90389@realtek.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Ricky Wu <ricky_wu@realtek.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Christian Loehle <cloehle@hyperstone.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/mmc/host/rtsx_pci_sdmmc.c |   30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

--- a/drivers/mmc/host/rtsx_pci_sdmmc.c
+++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
@@ -49,10 +49,7 @@ struct realtek_pci_sdmmc {
 	bool			double_clk;
 	bool			eject;
 	bool			initial_mode;
-	int			power_state;
-#define SDMMC_POWER_ON		1
-#define SDMMC_POWER_OFF		0
-
+	int			prev_power_state;
 	int			sg_count;
 	s32			cookie;
 	int			cookie_sg_count;
@@ -914,14 +911,21 @@ static int sd_set_bus_width(struct realt
 	return err;
 }
 
-static int sd_power_on(struct realtek_pci_sdmmc *host)
+static int sd_power_on(struct realtek_pci_sdmmc *host, unsigned char power_mode)
 {
 	struct rtsx_pcr *pcr = host->pcr;
 	int err;
 
-	if (host->power_state == SDMMC_POWER_ON)
+	if (host->prev_power_state == MMC_POWER_ON)
 		return 0;
 
+	if (host->prev_power_state == MMC_POWER_UP) {
+		rtsx_pci_write_register(pcr, SD_BUS_STAT, SD_CLK_TOGGLE_EN, 0);
+		goto finish;
+	}
+
+	msleep(100);
+
 	rtsx_pci_init_cmd(pcr);
 	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, CARD_SELECT, 0x07, SD_MOD_SEL);
 	rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, CARD_SHARE_MODE,
@@ -940,11 +944,17 @@ static int sd_power_on(struct realtek_pc
 	if (err < 0)
 		return err;
 
+	mdelay(1);
+
 	err = rtsx_pci_write_register(pcr, CARD_OE, SD_OUTPUT_EN, SD_OUTPUT_EN);
 	if (err < 0)
 		return err;
 
-	host->power_state = SDMMC_POWER_ON;
+	/* send at least 74 clocks */
+	rtsx_pci_write_register(pcr, SD_BUS_STAT, SD_CLK_TOGGLE_EN, SD_CLK_TOGGLE_EN);
+
+finish:
+	host->prev_power_state = power_mode;
 	return 0;
 }
 
@@ -953,7 +963,7 @@ static int sd_power_off(struct realtek_p
 	struct rtsx_pcr *pcr = host->pcr;
 	int err;
 
-	host->power_state = SDMMC_POWER_OFF;
+	host->prev_power_state = MMC_POWER_OFF;
 
 	rtsx_pci_init_cmd(pcr);
 
@@ -979,7 +989,7 @@ static int sd_set_power_mode(struct real
 	if (power_mode == MMC_POWER_OFF)
 		err = sd_power_off(host);
 	else
-		err = sd_power_on(host);
+		err = sd_power_on(host, power_mode);
 
 	return err;
 }
@@ -1417,7 +1427,7 @@ static int rtsx_pci_sdmmc_drv_probe(stru
 	host->mmc = mmc;
 	host->pdev = pdev;
 	host->cookie = -1;
-	host->power_state = SDMMC_POWER_OFF;
+	host->prev_power_state = MMC_POWER_OFF;
 	INIT_WORK(&host->work, sd_request);
 	platform_set_drvdata(pdev, host);
 	pcr->slots[RTSX_SD_CARD].p_dev = pdev;