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Date: Tue, 21 Jul 2009 00:27:23 +0200
From: Linus Walleij <linus.walleij@...ricsson.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
linux-kernel@...r.kernel.org
Cc: Pierre Ossman <pierre@...man.eu>,
linux-arm-kernel@...ts.arm.linux.org.uk,
Linus Walleij <linus.walleij@...ricsson.com>
Subject: [PATCH 2/2] Modify MMCI/PL180 to handle agressive clocking v7
This adds a few clk_enable()/clk_disable() calls to the MMCI
driver so as to handle an set_ios() request with clock
frequency set to 0 as an instruction to gate the block clock.
This also breaks out the clock setting code into its own
function to simplify the set_ios() function a bit.
Signed-off-by: Linus Walleij <linus.walleij@...ricsson.com>
---
drivers/mmc/host/mmci.c | 86 +++++++++++++++++++++++++++++++++++-----------
drivers/mmc/host/mmci.h | 3 +-
2 files changed, 67 insertions(+), 22 deletions(-)
diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index e1aa847..db09b69 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -37,8 +37,34 @@
static unsigned int fmax = 515633;
+/*
+ * This must be called with host->lock held
+ */
+static void mmci_set_clkreg(struct mmci_host *host, unsigned int desired)
+{
+ u32 clk = 0;
+
+ if (desired) {
+ if (desired >= host->mclk) {
+ clk = MCI_CLK_BYPASS;
+ host->cclk = host->mclk;
+ DBG(host, "MMCI: bypass clock divider, cclk = %u Hz\n", host->cclk);
+ } else {
+ clk = host->mclk / (2 * desired) - 1;
+ if (clk >= 256)
+ clk = 255;
+ host->cclk = host->mclk / (2 * (clk + 1));
+ DBG(host, "MMCI: divide cclk to %u Hz (divide %u by %u)\n", host->cclk, host->mclk, clk);
+ }
+ if (host->hw_designer == 0x80)
+ clk |= MCI_FCEN; /* Bug fix in ST IP block */
+ clk |= MCI_CLK_ENABLE;
+ }
+ writel(clk, host->base + MMCICLOCK);
+}
+
static void
-mmci_request_end(struct mmci_host *host, struct mmc_request *mrq)
+ mmci_request_end(struct mmci_host *host, struct mmc_request *mrq)
{
writel(0, host->base + MMCICOMMAND);
@@ -418,22 +444,7 @@ static void mmci_request(struct mmc_host *mmc, struct mmc_request *mrq)
static void mmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
struct mmci_host *host = mmc_priv(mmc);
- u32 clk = 0, pwr = 0;
-
- if (ios->clock) {
- if (ios->clock >= host->mclk) {
- clk = MCI_CLK_BYPASS;
- host->cclk = host->mclk;
- } else {
- clk = host->mclk / (2 * ios->clock) - 1;
- if (clk >= 256)
- clk = 255;
- host->cclk = host->mclk / (2 * (clk + 1));
- }
- if (host->hw_designer == 0x80)
- clk |= MCI_FCEN; /* Bug fix in ST IP block */
- clk |= MCI_CLK_ENABLE;
- }
+ u32 pwr = 0;
if (host->plat->translate_vdd)
pwr |= host->plat->translate_vdd(mmc_dev(mmc), ios->vdd);
@@ -464,12 +475,30 @@ static void mmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
}
}
- writel(clk, host->base + MMCICLOCK);
+ spin_lock(&host->lock);
+
+ /*
+ * Turn on clock whenever ios->clock transitions
+ * from 0 to !=0 and gate it off whenever ios->clock
+ * transitions from !=0 to 0.
+ */
+ if (host->iosclock == 0 && ios->clock != 0) {
+ clk_enable(host->clk);
+ mmci_set_clkreg(host, ios->clock);
+ } else if (host->iosclock != 0 && ios->clock == 0) {
+ clk_disable(host->clk);
+ }
+ host->iosclock = ios->clock;
if (host->pwr != pwr) {
host->pwr = pwr;
+ /* Clock may be gated (ios->clock still 0) */
+ clk_enable(host->clk);
writel(pwr, host->base + MMCIPOWER);
+ clk_disable(host->clk);
}
+
+ spin_unlock(&host->lock);
}
static const struct mmc_host_ops mmci_ops = {
@@ -546,6 +575,7 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
host->mclk = clk_get_rate(host->clk);
DBG(host, "eventual mclk rate: %u Hz\n", host->mclk);
}
+ host->iosclock = 0;
host->base = ioremap(dev->res.start, resource_size(&dev->res));
if (!host->base) {
ret = -ENOMEM;
@@ -615,6 +645,8 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
host->timer.expires = jiffies + HZ;
add_timer(&host->timer);
+ /* The first IOS will turn the clock on again */
+ clk_disable(host->clk);
return 0;
irq0_free:
@@ -646,17 +678,22 @@ static int __devexit mmci_remove(struct amba_device *dev)
mmc_remove_host(mmc);
+ /* framework may have gated the block clock */
+ clk_enable(host->clk);
+
writel(0, host->base + MMCIMASK0);
writel(0, host->base + MMCIMASK1);
writel(0, host->base + MMCICOMMAND);
writel(0, host->base + MMCIDATACTRL);
+ clk_disable(host->clk);
+
free_irq(dev->irq[0], host);
free_irq(dev->irq[1], host);
iounmap(host->base);
- clk_disable(host->clk);
+
clk_put(host->clk);
mmc_free_host(mmc);
@@ -677,8 +714,11 @@ static int mmci_suspend(struct amba_device *dev, pm_message_t state)
struct mmci_host *host = mmc_priv(mmc);
ret = mmc_suspend_host(mmc, state);
- if (ret == 0)
+ if (ret == 0) {
+ clk_enable(host->clk);
writel(0, host->base + MMCIMASK0);
+ clk_disable(host->clk);
+ }
}
return ret;
@@ -692,7 +732,11 @@ static int mmci_resume(struct amba_device *dev)
if (mmc) {
struct mmci_host *host = mmc_priv(mmc);
- writel(MCI_IRQENABLE, host->base + MMCIMASK0);
+ if (ret == 0) {
+ clk_enable(host->clk);
+ writel(MCI_IRQENABLE, host->base + MMCIMASK0);
+ clk_disable(host->clk);
+ }
ret = mmc_resume_host(mmc);
}
diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index 0441bac..796db94 100644
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -137,7 +137,7 @@
* The size of the FIFO in bytes.
*/
#define MCI_FIFOSIZE (16*4)
-
+
#define MCI_FIFOHALFSIZE (MCI_FIFOSIZE / 2)
#define NR_SG 16
@@ -158,6 +158,7 @@ struct mmci_host {
unsigned int mclk;
unsigned int cclk;
+ unsigned int iosclock;
u32 pwr;
struct mmc_platform_data *plat;
--
1.6.2.5
--
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