Support for cpu frequency changing.
Signed-off-by: Ben Dooks <[email protected]>
Index: linux-2.6.27-rc2-quilt3/drivers/mmc/host/s3cmci.c
===================================================================
--- linux-2.6.27-rc2-quilt3.orig/drivers/mmc/host/s3cmci.c 2008-08-12 20:10:07.000000000 +0100
+++ linux-2.6.27-rc2-quilt3/drivers/mmc/host/s3cmci.c 2008-08-12 20:12:39.000000000 +0100
@@ -13,6 +13,7 @@
#include <linux/clk.h>
#include <linux/mmc/host.h>
#include <linux/platform_device.h>
+#include <linux/cpufreq.h>
#include <linux/irq.h>
#include <linux/io.h>
@@ -1033,10 +1034,33 @@ static void s3cmci_request(struct mmc_ho
s3cmci_send_request(mmc);
}
+static void s3cmci_set_clk(struct s3cmci_host *host, struct mmc_ios *ios)
+{
+ u32 mci_psc;
+
+ /* Set clock */
+ for (mci_psc = 0; mci_psc < 255; mci_psc++) {
+ host->real_rate = host->clk_rate / (host->clk_div*(mci_psc+1));
+
+ if (host->real_rate <= ios->clock)
+ break;
+ }
+
+ if (mci_psc > 255)
+ mci_psc = 255;
+
+ host->prescaler = mci_psc;
+ writel(host->prescaler, host->base + S3C2410_SDIPRE);
+
+ /* If requested clock is 0, real_rate will be 0, too */
+ if (ios->clock == 0)
+ host->real_rate = 0;
+}
+
static void s3cmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
struct s3cmci_host *host = mmc_priv(mmc);
- u32 mci_psc, mci_con;
+ u32 mci_con;
/* Set the power state */
@@ -1074,23 +1098,7 @@ static void s3cmci_set_ios(struct mmc_ho
break;
}
- /* Set clock */
- for (mci_psc = 0; mci_psc < 255; mci_psc++) {
- host->real_rate = host->clk_rate / (host->clk_div*(mci_psc+1));
-
- if (host->real_rate <= ios->clock)
- break;
- }
-
- if (mci_psc > 255)
- mci_psc = 255;
-
- host->prescaler = mci_psc;
- writel(host->prescaler, host->base + S3C2410_SDIPRE);
-
- /* If requested clock is 0, real_rate will be 0, too */
- if (ios->clock == 0)
- host->real_rate = 0;
+ s3cmci_set_clk(host, ios);
/* Set CLOCK_ENABLE */
if (ios->clock)
@@ -1148,6 +1156,61 @@ static struct s3c24xx_mci_pdata s3cmci_d
* checks. Any zero fields to ensure reaonable defaults are picked. */
};
+#ifdef CONFIG_CPU_FREQ
+
+static int s3cmci_cpufreq_transition(struct notifier_block *nb,
+ unsigned long val, void *data)
+{
+ struct s3cmci_host *host;
+ struct mmc_host *mmc;
+ unsigned long newclk;
+ unsigned long flags;
+
+ host = container_of(nb, struct s3cmci_host, freq_transition);
+ newclk = clk_get_rate(host->clk);
+ mmc = host->mmc;
+
+ if ((val == CPUFREQ_PRECHANGE && host->clk_rate > newclk) ||
+ (val == CPUFREQ_POSTCHANGE && host->clk_rate < newclk)) {
+ spin_lock_irqsave(&mmc->lock, flags);
+
+ host->clk_rate = newclk;
+
+ if (mmc->ios.power_mode != MMC_POWER_OFF &&
+ mmc->ios.clock != 0)
+ s3cmci_set_clk(host, &mmc->ios);
+
+ spin_unlock_irqrestore(&mmc->lock, flags);
+ }
+
+ return 0;
+}
+
+static inline int s3cmci_cpufreq_register(struct s3cmci_host *host)
+{
+ host->freq_transition.notifier_call = s3cmci_cpufreq_transition;
+
+ return cpufreq_register_notifier(&host->freq_transition,
+ CPUFREQ_TRANSITION_NOTIFIER);
+}
+
+static inline void s3cmci_cpufreq_deregister(struct s3cmci_host *host)
+{
+ cpufreq_unregister_notifier(&host->freq_transition,
+ CPUFREQ_TRANSITION_NOTIFIER);
+}
+
+#else
+static inline int s3cmci_cpufreq_register(struct s3cmci_host *host)
+{
+ return 0;
+}
+
+static inline void s3cmci_cpufreq_deregister(struct s3cmci_host *host)
+{
+}
+#endif
+
static int __devinit s3cmci_probe(struct platform_device *pdev, int is2440)
{
struct s3cmci_host *host;
@@ -1298,10 +1361,16 @@ static int __devinit s3cmci_probe(struct
(host->is2440?"2440":""),
host->base, host->irq, host->irq_cd, host->dma);
+ ret = s3cmci_cpufreq_register(host);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to register cpufreq\n");
+ goto free_dmabuf;
+ }
+
ret = mmc_add_host(mmc);
if (ret) {
dev_err(&pdev->dev, "failed to add mmc host.\n");
- goto free_dmabuf;
+ goto free_cpufreq;
}
platform_set_drvdata(pdev, mmc);
@@ -1309,6 +1378,9 @@ static int __devinit s3cmci_probe(struct
return 0;
+ free_cpufreq:
+ s3cmci_cpufreq_deregister(host);
+
free_dmabuf:
clk_disable(host->clk);
@@ -1342,6 +1414,7 @@ static void s3cmci_shutdown(struct platf
if (host->irq_cd >= 0)
free_irq(host->irq_cd, host);
+ s3cmci_cpufreq_deregister(host);
mmc_remove_host(mmc);
clk_disable(host->clk);
}
Index: linux-2.6.27-rc2-quilt3/drivers/mmc/host/s3cmci.h
===================================================================
--- linux-2.6.27-rc2-quilt3.orig/drivers/mmc/host/s3cmci.h 2008-08-12 20:10:07.000000000 +0100
+++ linux-2.6.27-rc2-quilt3/drivers/mmc/host/s3cmci.h 2008-08-12 20:10:29.000000000 +0100
@@ -67,4 +67,8 @@ struct s3cmci_host {
unsigned int ccnt, dcnt;
struct tasklet_struct pio_tasklet;
+
+#ifdef CONFIG_CPU_FREQ
+ struct notifier_block freq_transition;
+#endif
};
--
Ben ([email protected], http://www.fluff.org/)
'a smiley only costs 4 bytes'
On Fri, 10 Oct 2008 11:32:23 +0100
Ben Dooks <[email protected]> wrote:
> + host = container_of(nb, struct s3cmci_host, freq_transition);
> + newclk = clk_get_rate(host->clk);
> + mmc = host->mmc;
> +
> + if ((val == CPUFREQ_PRECHANGE && host->clk_rate > newclk) ||
> + (val == CPUFREQ_POSTCHANGE && host->clk_rate < newclk)) {
Isn't this backwards? The goal should be to avoid overclocking the
card, so if the old clock (which I assume is clk_rate) is slower than
the new clock (newclk), then we should adjust before the change happens,
temporarily underclocking the card.
(and vice versa for when the old clock is faster than the new clock)
--
-- Pierre Ossman
Linux kernel, MMC maintainer http://www.kernel.org
rdesktop, core developer http://www.rdesktop.org
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