mmc: rtsx: add 74 Clocks in power on flow

BugLink: https://bugs.launchpad.net/bugs/1963615

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>
(cherry picked from commit 1f311c9 linux-next)
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Timo Aaltonen <timo.aaltonen@canonical.com>

drivers/mmc/host/rtsx_pci_sdmmc.c

@@ -38,10 +38,7 @@ 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;
@@ -905,17 +902,22 @@ static int sd_set_bus_width(struct realtek_pci_sdmmc *host,
 	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;
 	struct mmc_host *mmc = host->mmc;
 	int err;
 	u32 val;
 	u8 test_mode;
 
-	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);
@@ -936,10 +938,15 @@ static int sd_power_on(struct realtek_pci_sdmmc *host)
 	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;
 
+	/* send at least 74 clocks */
+	rtsx_pci_write_register(pcr, SD_BUS_STAT, SD_CLK_TOGGLE_EN, SD_CLK_TOGGLE_EN);
+
 	if (PCI_PID(pcr) == PID_5261) {
 		/*
 		 * If test mode is set switch to SD Express mandatorily,
@@ -964,7 +971,8 @@ static int sd_power_on(struct realtek_pci_sdmmc *host)
 		}
 	}
 
-	host->power_state = SDMMC_POWER_ON;
+finish:
+	host->prev_power_state = power_mode;
 	return 0;
 }
 
@@ -973,7 +981,7 @@ static int sd_power_off(struct realtek_pci_sdmmc *host)
 	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);
 
@@ -999,7 +1007,7 @@ static int sd_set_power_mode(struct realtek_pci_sdmmc *host,
 	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;
 }
@@ -1482,10 +1490,11 @@ static int rtsx_pci_sdmmc_drv_probe(struct platform_device *pdev)
 
 	host = mmc_priv(mmc);
 	host->pcr = pcr;
+	mmc->ios.power_delay_ms = 5;
 	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;