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Commit 01730558 authored by Doug Anderson's avatar Doug Anderson Committed by Ulf Hansson
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mmc: dw_mmc: Support voltage changes 



For UHS cards we need the ability to switch voltages from 3.3V to
1.8V.  Add support to the dw_mmc driver to handle this.  Note that
dw_mmc needs a little bit of extra code since the interface needs a
special bit programmed to the CMD register while CMD11 is progressing.
This means adding a few extra states to the state machine to track.

Signed-off-by: default avatarDoug Anderson <dianders@chromium.org>
Signed-off-by: default avatarYuvaraj Kumar C D <yuvaraj.cd@samsung.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 51da2240

drivers/mmc/host/dw_mmc.c

+128 −9
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/irq.h>

#include <linux/mmc/host.h>

#include <linux/mmc/mmc.h>

#include <linux/mmc/sd.h>

#include <linux/mmc/sdio.h>

#include <linux/mmc/dw_mmc.h>

#include <linux/bitops.h>
@@ -234,10 +235,13 @@ static void dw_mci_init_debugfs(struct dw_mci_slot *slot) 
}

#endif /* defined(CONFIG_DEBUG_FS) */



static void mci_send_cmd(struct dw_mci_slot *slot, u32 cmd, u32 arg);



static u32 dw_mci_prepare_command(struct mmc_host *mmc, struct mmc_command *cmd)

{

	struct mmc_data	*data;

	struct dw_mci_slot *slot = mmc_priv(mmc);

	struct dw_mci *host = slot->host;

	const struct dw_mci_drv_data *drv_data = slot->host->drv_data;

	u32 cmdr;

	cmd->error = -EINPROGRESS;
@@ -253,6 +257,34 @@ static u32 dw_mci_prepare_command(struct mmc_host *mmc, struct mmc_command *cmd) 
	else if (cmd->opcode != MMC_SEND_STATUS && cmd->data)

		cmdr |= SDMMC_CMD_PRV_DAT_WAIT;



	if (cmd->opcode == SD_SWITCH_VOLTAGE) {

		u32 clk_en_a;



		/* Special bit makes CMD11 not die */

		cmdr |= SDMMC_CMD_VOLT_SWITCH;



		/* Change state to continue to handle CMD11 weirdness */

		WARN_ON(slot->host->state != STATE_SENDING_CMD);

		slot->host->state = STATE_SENDING_CMD11;



		/*

		 * We need to disable low power mode (automatic clock stop)

		 * while doing voltage switch so we don't confuse the card,

		 * since stopping the clock is a specific part of the UHS

		 * voltage change dance.

		 *

		 * Note that low power mode (SDMMC_CLKEN_LOW_PWR) will be

		 * unconditionally turned back on in dw_mci_setup_bus() if it's

		 * ever called with a non-zero clock.  That shouldn't happen

		 * until the voltage change is all done.

		 */

		clk_en_a = mci_readl(host, CLKENA);

		clk_en_a &= ~(SDMMC_CLKEN_LOW_PWR << slot->id);

		mci_writel(host, CLKENA, clk_en_a);

		mci_send_cmd(slot, SDMMC_CMD_UPD_CLK |

			     SDMMC_CMD_PRV_DAT_WAIT, 0);

	}



	if (cmd->flags & MMC_RSP_PRESENT) {

		/* We expect a response, so set this bit */

		cmdr |= SDMMC_CMD_RESP_EXP;
@@ -775,11 +807,15 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) 
	unsigned int clock = slot->clock;

	u32 div;

	u32 clk_en_a;

	u32 sdmmc_cmd_bits = SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT;



	/* We must continue to set bit 28 in CMD until the change is complete */

	if (host->state == STATE_WAITING_CMD11_DONE)

		sdmmc_cmd_bits |= SDMMC_CMD_VOLT_SWITCH;



	if (!clock) {

		mci_writel(host, CLKENA, 0);

		mci_send_cmd(slot,

			     SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);

		mci_send_cmd(slot, sdmmc_cmd_bits, 0);

	} else if (clock != host->current_speed || force_clkinit) {

		div = host->bus_hz / clock;

		if (host->bus_hz % clock && host->bus_hz > clock)
@@ -803,15 +839,13 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) 
		mci_writel(host, CLKSRC, 0);



		/* inform CIU */

		mci_send_cmd(slot,

			     SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);

		mci_send_cmd(slot, sdmmc_cmd_bits, 0);



		/* set clock to desired speed */

		mci_writel(host, CLKDIV, div);



		/* inform CIU */

		mci_send_cmd(slot,

			     SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);

		mci_send_cmd(slot, sdmmc_cmd_bits, 0);



		/* enable clock; only low power if no SDIO */

		clk_en_a = SDMMC_CLKEN_ENABLE << slot->id;
@@ -820,8 +854,7 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) 
		mci_writel(host, CLKENA, clk_en_a);



		/* inform CIU */

		mci_send_cmd(slot,

			     SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);

		mci_send_cmd(slot, sdmmc_cmd_bits, 0);



		/* keep the clock with reflecting clock dividor */

		slot->__clk_old = clock << div;
@@ -897,6 +930,17 @@ static void dw_mci_queue_request(struct dw_mci *host, struct dw_mci_slot *slot, 


	slot->mrq = mrq;



	if (host->state == STATE_WAITING_CMD11_DONE) {

		dev_warn(&slot->mmc->class_dev,

			 "Voltage change didn't complete\n");

		/*

		 * this case isn't expected to happen, so we can

		 * either crash here or just try to continue on

		 * in the closest possible state

		 */

		host->state = STATE_IDLE;

	}



	if (host->state == STATE_IDLE) {

		host->state = STATE_SENDING_CMD;

		dw_mci_start_request(host, slot);
@@ -973,6 +1017,9 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) 
	/* Slot specific timing and width adjustment */

	dw_mci_setup_bus(slot, false);



	if (slot->host->state == STATE_WAITING_CMD11_DONE && ios->clock != 0)

		slot->host->state = STATE_IDLE;



	switch (ios->power_mode) {

	case MMC_POWER_UP:

		if (!IS_ERR(mmc->supply.vmmc)) {
@@ -1016,6 +1063,59 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) 
	}

}



static int dw_mci_card_busy(struct mmc_host *mmc)

{

	struct dw_mci_slot *slot = mmc_priv(mmc);

	u32 status;



	/*

	 * Check the busy bit which is low when DAT[3:0]

	 * (the data lines) are 0000

	 */

	status = mci_readl(slot->host, STATUS);



	return !!(status & SDMMC_STATUS_BUSY);

}



static int dw_mci_switch_voltage(struct mmc_host *mmc, struct mmc_ios *ios)

{

	struct dw_mci_slot *slot = mmc_priv(mmc);

	struct dw_mci *host = slot->host;

	u32 uhs;

	u32 v18 = SDMMC_UHS_18V << slot->id;

	int min_uv, max_uv;

	int ret;



	/*

	 * Program the voltage.  Note that some instances of dw_mmc may use

	 * the UHS_REG for this.  For other instances (like exynos) the UHS_REG

	 * does no harm but you need to set the regulator directly.  Try both.

	 */

	uhs = mci_readl(host, UHS_REG);

	if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330) {

		min_uv = 2700000;

		max_uv = 3600000;

		uhs &= ~v18;

	} else {

		min_uv = 1700000;

		max_uv = 1950000;

		uhs |= v18;

	}

	if (!IS_ERR(mmc->supply.vqmmc)) {

		ret = regulator_set_voltage(mmc->supply.vqmmc, min_uv, max_uv);



		if (ret) {

			dev_err(&mmc->class_dev,

					 "Regulator set error %d: %d - %d\n",

					 ret, min_uv, max_uv);

			return ret;

		}

	}

	mci_writel(host, UHS_REG, uhs);



	return 0;

}



static int dw_mci_get_ro(struct mmc_host *mmc)

{

	int read_only;
@@ -1158,6 +1258,9 @@ static const struct mmc_host_ops dw_mci_ops = { 
	.get_cd			= dw_mci_get_cd,

	.enable_sdio_irq	= dw_mci_enable_sdio_irq,

	.execute_tuning		= dw_mci_execute_tuning,

	.card_busy		= dw_mci_card_busy,

	.start_signal_voltage_switch = dw_mci_switch_voltage,



};



static void dw_mci_request_end(struct dw_mci *host, struct mmc_request *mrq)
@@ -1181,6 +1284,10 @@ static void dw_mci_request_end(struct dw_mci *host, struct mmc_request *mrq) 
		dw_mci_start_request(host, slot);

	} else {

		dev_vdbg(host->dev, "list empty\n");



		if (host->state == STATE_SENDING_CMD11)

			host->state = STATE_WAITING_CMD11_DONE;

		else

			host->state = STATE_IDLE;

	}
@@ -1292,8 +1399,10 @@ static void dw_mci_tasklet_func(unsigned long priv) 


		switch (state) {

		case STATE_IDLE:

		case STATE_WAITING_CMD11_DONE:

			break;



		case STATE_SENDING_CMD11:

		case STATE_SENDING_CMD:

			if (!test_and_clear_bit(EVENT_CMD_COMPLETE,

						&host->pending_events))
@@ -1894,6 +2003,14 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id) 
	}



	if (pending) {

		/* Check volt switch first, since it can look like an error */

		if ((host->state == STATE_SENDING_CMD11) &&

		    (pending & SDMMC_INT_VOLT_SWITCH)) {

			mci_writel(host, RINTSTS, SDMMC_INT_VOLT_SWITCH);

			pending &= ~SDMMC_INT_VOLT_SWITCH;

			dw_mci_cmd_interrupt(host, pending);

		}



		if (pending & DW_MCI_CMD_ERROR_FLAGS) {

			mci_writel(host, RINTSTS, DW_MCI_CMD_ERROR_FLAGS);

			host->cmd_status = pending;
@@ -1999,7 +2116,9 @@ static void dw_mci_work_routine_card(struct work_struct *work) 


					switch (host->state) {

					case STATE_IDLE:

					case STATE_WAITING_CMD11_DONE:

						break;

					case STATE_SENDING_CMD11:

					case STATE_SENDING_CMD:

						mrq->cmd->error = -ENOMEDIUM;

						if (!mrq->data)

drivers/mmc/host/dw_mmc.h

+4 −1
Original line number Diff line number Diff line
@@ -99,6 +99,7 @@ 
#define SDMMC_INT_HLE			BIT(12)

#define SDMMC_INT_FRUN			BIT(11)

#define SDMMC_INT_HTO			BIT(10)

#define SDMMC_INT_VOLT_SWITCH		BIT(10) /* overloads bit 10! */

#define SDMMC_INT_DRTO			BIT(9)

#define SDMMC_INT_RTO			BIT(8)

#define SDMMC_INT_DCRC			BIT(7)
@@ -113,6 +114,7 @@ 
/* Command register defines */

#define SDMMC_CMD_START			BIT(31)

#define SDMMC_CMD_USE_HOLD_REG	BIT(29)

#define SDMMC_CMD_VOLT_SWITCH		BIT(28)

#define SDMMC_CMD_CCS_EXP		BIT(23)

#define SDMMC_CMD_CEATA_RD		BIT(22)

#define SDMMC_CMD_UPD_CLK		BIT(21)
@@ -130,6 +132,7 @@ 
/* Status register defines */

#define SDMMC_GET_FCNT(x)		(((x)>>17) & 0x1FFF)

#define SDMMC_STATUS_DMA_REQ		BIT(31)

#define SDMMC_STATUS_BUSY		BIT(9)

/* FIFOTH register defines */

#define SDMMC_SET_FIFOTH(m, r, t)	(((m) & 0x7) << 28 | \

					 ((r) & 0xFFF) << 16 | \
@@ -150,7 +153,7 @@ 
#define SDMMC_GET_VERID(x)		((x) & 0xFFFF)

/* Card read threshold */

#define SDMMC_SET_RD_THLD(v, x)		(((v) & 0x1FFF) << 16 | (x))



#define SDMMC_UHS_18V			BIT(0)

/* All ctrl reset bits */

#define SDMMC_CTRL_ALL_RESET_FLAGS \

	(SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET | SDMMC_CTRL_DMA_RESET)

include/linux/mmc/dw_mmc.h

+2 −0
Original line number Diff line number Diff line
@@ -26,6 +26,8 @@ enum dw_mci_state { 
	STATE_DATA_BUSY,

	STATE_SENDING_STOP,

	STATE_DATA_ERROR,

	STATE_SENDING_CMD11,

	STATE_WAITING_CMD11_DONE,

};



enum {