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Date: Tue, 2 Dec 2014 12:49:56 -0800
From: Doug Anderson <dianders@...omium.org>
To: Jaehoon Chung <jh80.chung@...sung.com>,
Seungwon Jeon <tgih.jun@...sung.com>,
Ulf Hansson <ulf.hansson@...aro.org>
Cc: Alim Akhtar <alim.akhtar@...sung.com>,
Sonny Rao <sonnyrao@...omium.org>,
Andrew Bresticker <abrestic@...omium.org>,
Heiko Stuebner <heiko@...ech.de>,
Doug Anderson <dianders@...omium.org>, chris@...ntf.net,
linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v4 2/3] mmc: dw_mmc: Cleanup disable of low power mode w/ SDIO interrupts
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@...omium.org>
---
Changes in v3: None
Changes in v2:
- Fixed "|" to "&".
drivers/mmc/host/dw_mmc.c | 69 ++++++++++++++++++++++++-----------------------
drivers/mmc/host/dw_mmc.h | 1 +
2 files changed, 36 insertions(+), 34 deletions(-)
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 67c0451..ae10a02 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -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)
diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
index 0d0f7a2..d27d4c0 100644
--- a/drivers/mmc/host/dw_mmc.h
+++ b/drivers/mmc/host/dw_mmc.h
@@ -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;
};
--
2.2.0.rc0.207.ga3a616c
--
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