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authorDoug Anderson <dianders@chromium.org>2012-07-25 08:33:17 -0700
committerChris Ball <cjb@laptop.org>2012-09-04 13:58:10 -0400
commit9623b5b9192b349bcadb31cce159072a78ac6972 (patch)
tree71441fdd2571d4262830a8562dbd6aa06f07785e
parente74f3a9c993a088f0a067e13941075e4acb7300a (diff)
downloadlinux-linaro-stable-9623b5b9192b349bcadb31cce159072a78ac6972.tar.gz
mmc: dw_mmc: Disable low power mode if SDIO interrupts are used
The documentation for the dw_mmc part says that the low power mode should normally only be set for MMC and SD memory and should be turned off for SDIO cards that need interrupts detected. The best place I could find to do this is when the SDIO interrupt was first enabled. I rely on the fact that dw_mci_setup_bus() will be called when it's time to reenable. Signed-off-by: Doug Anderson <dianders@chromium.org> Acked-by: Seungwon Jeon <tgih.jun@samsung.com> Signed-off-by: Chris Ball <cjb@laptop.org>
-rw-r--r--drivers/mmc/host/dw_mmc.c41
1 files changed, 38 insertions, 3 deletions
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index cf8511b80782..af40d227bece 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -627,6 +627,7 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot)
{
struct dw_mci *host = slot->host;
u32 div;
+ u32 clk_en_a;
if (slot->clock != host->current_speed) {
div = host->bus_hz / slot->clock;
@@ -659,9 +660,11 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot)
mci_send_cmd(slot,
SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
- /* enable clock */
- mci_writel(host, CLKENA, ((SDMMC_CLKEN_ENABLE |
- SDMMC_CLKEN_LOW_PWR) << slot->id));
+ /* 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->id)))
+ clk_en_a |= SDMMC_CLKEN_LOW_PWR << slot->id;
+ mci_writel(host, CLKENA, clk_en_a);
/* inform CIU */
mci_send_cmd(slot,
@@ -862,6 +865,30 @@ 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)
+{
+ 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);
+
+ 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);
+ }
+}
+
static void dw_mci_enable_sdio_irq(struct mmc_host *mmc, int enb)
{
struct dw_mci_slot *slot = mmc_priv(mmc);
@@ -871,6 +898,14 @@ 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->id)));
} else {