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Commit b24c8b26 authored by Doug Anderson's avatar Doug Anderson Committed by Ulf Hansson
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mmc: dw_mmc: Cleanup disable of low power mode w/ SDIO interrupts 



In the patch (9623b5b9 mmc: dw_mmc: Disable low power mode if SDIO
interrupts are used) I added code that disabled the low power mode of
dw_mmc when SDIO interrupts are used.  That code worked but always
felt a little hacky because we ended up disabling low power as a side
effect of the first enable_sdio_irq() call.  That wouldn't be so bad
except that disabling low power involves a complicated process of
writing to the CMD/CMDARG registers and that extra process makes it
difficult to cleanly the read-modify-write race in
dw_mci_enable_sdio_irq() (see future patch in the series).

Change the code to take advantage of the init_card() callback of the
mmc core to do this right at bootup.

Signed-off-by: default avatarDoug Anderson <dianders@chromium.org>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent eac86321

drivers/mmc/host/dw_mmc.c

+35 −34
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/stat.h>

#include <linux/delay.h>

#include <linux/irq.h>

#include <linux/mmc/card.h>

#include <linux/mmc/host.h>

#include <linux/mmc/mmc.h>

#include <linux/mmc/sd.h>
@@ -926,7 +927,7 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) 


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

		clk_en_a = SDMMC_CLKEN_ENABLE << slot->id;

		if (!(mci_readl(host, INTMASK) & SDMMC_INT_SDIO(slot->sdio_id)))

		if (!test_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags))

			clk_en_a |= SDMMC_CLKEN_LOW_PWR << slot->id;

		mci_writel(host, CLKENA, clk_en_a);
@@ -1245,29 +1246,39 @@ static int dw_mci_get_cd(struct mmc_host *mmc) 
	return present;

}



static void dw_mci_init_card(struct mmc_host *mmc, struct mmc_card *card)

{

	struct dw_mci_slot *slot = mmc_priv(mmc);

	struct dw_mci *host = slot->host;



	/*

 * Disable lower power mode.

 *

	 * Low power mode will stop the card clock when idle.  According to the

	 * description of the CLKENA register we should disable low power mode

	 * for SDIO cards if we need SDIO interrupts to work.

 *

 * This function is fast if low power mode is already disabled.

	 */

static void dw_mci_disable_low_power(struct dw_mci_slot *slot)

{

	struct dw_mci *host = slot->host;

	u32 clk_en_a;

	if (mmc->caps & MMC_CAP_SDIO_IRQ) {

		const u32 clken_low_pwr = SDMMC_CLKEN_LOW_PWR << slot->id;

		u32 clk_en_a_old;

		u32 clk_en_a;



	clk_en_a = mci_readl(host, CLKENA);

		clk_en_a_old = mci_readl(host, CLKENA);



	if (clk_en_a & clken_low_pwr) {

		mci_writel(host, CLKENA, clk_en_a & ~clken_low_pwr);

		if (card->type == MMC_TYPE_SDIO ||

		    card->type == MMC_TYPE_SD_COMBO) {

			set_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags);

			clk_en_a = clk_en_a_old & ~clken_low_pwr;

		} else {

			clear_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags);

			clk_en_a = clk_en_a_old | clken_low_pwr;

		}



		if (clk_en_a != clk_en_a_old) {

			mci_writel(host, CLKENA, clk_en_a);

			mci_send_cmd(slot, SDMMC_CMD_UPD_CLK |

				     SDMMC_CMD_PRV_DAT_WAIT, 0);

		}

	}

}



static void dw_mci_enable_sdio_irq(struct mmc_host *mmc, int enb)

{
@@ -1277,21 +1288,11 @@ static void dw_mci_enable_sdio_irq(struct mmc_host *mmc, int enb) 


	/* Enable/disable Slot Specific SDIO interrupt */

	int_mask = mci_readl(host, INTMASK);

	if (enb) {

		/*

		 * Turn off low power mode if it was enabled.  This is a bit of

		 * a heavy operation and we disable / enable IRQs a lot, so

		 * we'll leave low power mode disabled and it will get

		 * re-enabled again in dw_mci_setup_bus().

		 */

		dw_mci_disable_low_power(slot);



		mci_writel(host, INTMASK,

			   (int_mask | SDMMC_INT_SDIO(slot->sdio_id)));

	} else {

		mci_writel(host, INTMASK,

			   (int_mask & ~SDMMC_INT_SDIO(slot->sdio_id)));

	}

	if (enb)

		int_mask |= SDMMC_INT_SDIO(slot->sdio_id);

	else

		int_mask &= ~SDMMC_INT_SDIO(slot->sdio_id);

	mci_writel(host, INTMASK, int_mask);

}



static int dw_mci_execute_tuning(struct mmc_host *mmc, u32 opcode)
@@ -1337,7 +1338,7 @@ static const struct mmc_host_ops dw_mci_ops = { 
	.execute_tuning		= dw_mci_execute_tuning,

	.card_busy		= dw_mci_card_busy,

	.start_signal_voltage_switch = dw_mci_switch_voltage,



	.init_card		= dw_mci_init_card,

};



static void dw_mci_request_end(struct dw_mci *host, struct mmc_request *mrq)

drivers/mmc/host/dw_mmc.h

+1 −0
Original line number Diff line number Diff line
@@ -244,6 +244,7 @@ struct dw_mci_slot { 
	unsigned long		flags;

#define DW_MMC_CARD_PRESENT	0

#define DW_MMC_CARD_NEED_INIT	1

#define DW_MMC_CARD_NO_LOW_PWR	2

	int			id;

	int			sdio_id;

};