From 1917452ca1fcbb6ba52916b7535f453d86d55a1c Mon Sep 17 00:00:00 2001
From: Madhav Singh <singh.mad...@samsung.com>,Nitish
Ambastha<nitis...@samsung.com>
Date: Fri, 2 Jul 2010 17:28:57 +0530
Subject: [PATCH] sdhci-clk-gating-support
This patch implements clock gating support in sdhci layer.It will enable the
clock when
host controller start sending request to attached device and will disable it
once it
finish the command.
Signed-off-by:Madhav Chauhan <singh.mad...@samsung.com>, Nitish
Ambastha<nitis...@samsung.com>
Signed-off-by:Kyungmin Park <kyungmin.p...@samsung.com>
---
drivers/mmc/host/sdhci.c | 34 ++++++++++++++++++++++++++++++++++
drivers/mmc/host/sdhci.h | 8 ++++++++
2 files changed, 42 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index c6d1bd8..54f606e 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1102,6 +1102,8 @@ static void sdhci_request(struct mmc_host *mmc, struct
mmc_request *mrq)
host = mmc_priv(mmc);
spin_lock_irqsave(&host->lock, flags);
+
+ sdhci_clk_enable(host); /*Enable clock here as actual transfer starts
now*/
WARN_ON(host->mrq != NULL);
@@ -1310,6 +1312,8 @@ static void sdhci_tasklet_finish(unsigned long param)
sdhci_reset(host, SDHCI_RESET_DATA);
}
+ sdhci_clk_disable(host); /*Disable clock here as command has been
processed*/
+
host->mrq = NULL;
host->cmd = NULL;
host->data = NULL;
@@ -1597,6 +1601,8 @@ int sdhci_suspend_host(struct sdhci_host *host,
pm_message_t state)
sdhci_disable_card_detection(host);
+ sdhci_clk_enable(host); /*Enable clock as some mmc core side dependency
is on Host*/
+
ret = mmc_suspend_host(host->mmc);
if (ret)
return ret;
@@ -1626,6 +1632,9 @@ int sdhci_resume_host(struct sdhci_host *host)
mmiowb();
ret = mmc_resume_host(host->mmc);
+
+ sdhci_clk_disable(host); /*Now device has wake up disable it*/
+
sdhci_enable_card_detection(host);
return ret;
@@ -1654,6 +1663,9 @@ struct sdhci_host *sdhci_alloc_host(struct device
*dev,
return ERR_PTR(-ENOMEM);
host = mmc_priv(mmc);
+ host->user=0; /*For Clock gating*/
+ host->clk_restore=0;
+
host->mmc = mmc;
return host;
@@ -1984,6 +1996,28 @@ void sdhci_free_host(struct sdhci_host *host)
EXPORT_SYMBOL_GPL(sdhci_free_host);
+void sdhci_clk_enable(struct sdhci_host *host)
+{
+ if(!host->user){
+ if(host->clk_restore && host->clock==0)
+ sdhci_set_clock(host,host->clk_restore);
+ }
+ host->user++;
+}
+EXPORT_SYMBOL_GPL(sdhci_clk_enable);
+
+void sdhci_clk_disable(struct sdhci_host *host)
+{
+ host->user--;
+ if(!host->user)
+ if(host->clock!=0){
+ host->clk_restore=host->clock;
+ sdhci_set_clock(host,0);
+ }
+}
+EXPORT_SYMBOL_GPL(sdhci_clk_disable);
+
+
/*****************************************************************************\
** * Driver init/exit*diff --git a/drivers/mmc/host/sdhci.h
b/drivers/mmc/host/sdhci.hindex c846813..092587d 100644---
a/drivers/mmc/host/sdhci.h+++ b/drivers/mmc/host/sdhci.h@@ -292,6 +292,9 @@
struct sdhci_host { struct timer_list timer; /* Timer for timeouts */+
unsigned int clk_restore; /*For Clock Gating*/+ unsigned int user;+ unsigned
long private[0] ____cacheline_aligned; };@@ -410,6 +413,11 @@ static inline
void *sdhci_priv(struct sdhci_host *host) extern int sdhci_add_host(struct
sdhci_host *host); extern void sdhci_remove_host(struct sdhci_host *host, int
dead);+/*For Clock Gating*/+extern void sdhci_clk_enable(struct sdhci_host
*host);+extern void sdhci_clk_disable(struct sdhci_host *host);++ #ifdef
CONFIG_PM extern int sdhci_suspend_host(struct sdhci_host *host, pm_message_t
state); extern int sdhci_resume_host(struct sdhci_host *host);--1.6.0.4
--
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