>From 7554ead744bfdc7304a7ae9fb227212bf548161a Mon Sep 17 00:00:00 2001
From: Zhangfei Gao <[email protected]>
Date: Wed, 5 Jan 2011 17:21:00 -0500
Subject: [PATCH] mmc: sdhci stop SDCLK during asynchronous interrupt peroid
V3 controller could stop SDCLK during asynchronous interrupt peroid
to save power, via set SDHCI_CTRL2_AINT bit 14 of
SDHCI_HOST_CONTROL2(0x3e)
Two conditions:
1. card support asynchronous interrupt
2. Asynchronous interrupt support is set to 1 in the capabilities
register.
How to enable: mmc->caps |= MMC_CAP_CLOCK_GATE
Signed-off-by: Zhangfei Gao <[email protected]>
---
drivers/mmc/host/sdhci.c | 14 ++++++++++++++
drivers/mmc/host/sdhci.h | 2 ++
include/linux/mmc/host.h | 2 ++
3 files changed, 18 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index aafbb42..946b947 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1261,6 +1261,15 @@ static void sdhci_set_ios(struct mmc_host *mmc,
struct mmc_ios *ios)
if(host->quirks & SDHCI_QUIRK_RESET_CMD_DATA_ON_IOS)
sdhci_reset(host, SDHCI_RESET_CMD | SDHCI_RESET_DATA);
+ if (mmc->caps & MMC_CAP_CLOCK_GATE) {
+ u16 con;
+
+ con = readw(host->ioaddr + SDHCI_HOST_CONTROL2);
+ con |= SDHCI_CTRL2_AINT;
+ writew(con, host->ioaddr + SDHCI_HOST_CONTROL2);
+ }
+
+
out:
mmiowb();
spin_unlock_irqrestore(&host->lock, flags);
@@ -1808,6 +1817,11 @@ int sdhci_add_host(struct sdhci_host *host)
mmc->caps |= (MMC_CAP_1_8V_DDR);
}
+ if (mmc->caps & MMC_CAP_CLOCK_GATE) {
+ if (!(caps & SDHCI_CAN_ASYN_INT))
+ mmc->caps &= ~MMC_CAP_CLOCK_GATE;
+ }
+
if (host->quirks & SDHCI_QUIRK_FORCE_DMA)
host->flags |= SDHCI_USE_SDMA;
else if (!(caps & SDHCI_CAN_DO_SDMA))
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index c4bd5dd..907de87 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -153,6 +153,7 @@
#define SDHCI_CTRL2_SDR104 0x0003
#define SDHCI_CTRL2_DDR50 0x0004
#define SDHCI_CTRL2_1_8V 0x0008
+#define SDHCI_CTRL2_AINT 0x4000
#define SDHCI_CAPABILITIES 0x40
#define SDHCI_TIMEOUT_CLK_MASK 0x0000003F
@@ -172,6 +173,7 @@
#define SDHCI_CAN_VDD_300 0x02000000
#define SDHCI_CAN_VDD_180 0x04000000
#define SDHCI_CAN_64BIT 0x10000000
+#define SDHCI_CAN_ASYN_INT 0x20000000
#define SDHCI_CAPABILITIES_1 0x44
#define SDHCI_CAN_SDR50 0x00000001
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index bcb793e..2a53a94 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -173,6 +173,8 @@ struct mmc_host {
/* DDR mode at 1.2V */
#define MMC_CAP_POWER_OFF_CARD (1 << 13) /* Can power off after boot */
#define MMC_CAP_BUS_WIDTH_TEST (1 << 14) /* CMD14/CMD19 bus width ok */
+#define MMC_CAP_CLOCK_GATE (1 << 15) /* V3 controller */
+ /* support clock gating */
mmc_pm_flag_t pm_caps; /* supported pm features */
--
1.7.0.4
--
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