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mmc: dw_mmc: Cleanup disable of low power mode w/ SDIO interrupts

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In the patch (9623b5b 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: Doug Anderson <dianders@chromium.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Doug Anderson 2014-12-02 15:42:46 -08:00 committed by Ulf Hansson
parent eac86321b5
commit b24c8b2601
2 changed files with 36 additions and 34 deletions
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69
drivers/mmc/host/dw_mmc.c
View File

@ -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);
@ -1245,27 +1246,37 @@ static int dw_mci_get_cd(struct mmc_host *mmc)
return present;
}
/*
* 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)
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;
u32 clk_en_a;
const u32 clken_low_pwr = SDMMC_CLKEN_LOW_PWR << slot->id;
clk_en_a = mci_readl(host, CLKENA);
/*
* 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.
*/
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;
if (clk_en_a & clken_low_pwr) {
mci_writel(host, CLKENA, clk_en_a & ~clken_low_pwr);
mci_send_cmd(slot, SDMMC_CMD_UPD_CLK |
SDMMC_CMD_PRV_DAT_WAIT, 0);
clk_en_a_old = mci_readl(host, CLKENA);
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);
}
}
}
@ -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)

1
drivers/mmc/host/dw_mmc.h
View File

@ -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;
};