ARM: 7280/1: mmc: mmci: Cache MMCICLOCK and MMCIPOWER register

Instead of reading a register value everytime we need to
apply a new value for it, maintain a cached copy for it.
This also means we are able to skip writes that are not
needed.

Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 29 insertions, 12 deletions

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 1f8832699cdf..f36d8b8c891f 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -121,6 +121,28 @@ static struct variant_data variant_ux500v2 = {
 /*
  * This must be called with host->lock held
  */
+static void mmci_write_clkreg(struct mmci_host *host, u32 clk)
+{
+        if (host->clk_reg != clk) {
+                host->clk_reg = clk;
+                writel(clk, host->base + MMCICLOCK);
+        }
+}
+
+/*
+ * This must be called with host->lock held
+ */
+static void mmci_write_pwrreg(struct mmci_host *host, u32 pwr)
+{
+        if (host->pwr_reg != pwr) {
+                host->pwr_reg = pwr;
+                writel(pwr, host->base + MMCIPOWER);
+        }
+}
+
+/*
+ * This must be called with host->lock held
+ */
 static void mmci_set_clkreg(struct mmci_host *host, unsigned int desired)
 {
         struct variant_data *variant = host->variant;
@@ -165,7 +187,7 @@ static void mmci_set_clkreg(struct mmci_host *host, unsigned int desired)
         if (host->mmc->ios.bus_width == MMC_BUS_WIDTH_8)
                 clk |= MCI_ST_8BIT_BUS;
 
-        writel(clk, host->base + MMCICLOCK);
+        mmci_write_clkreg(host, clk);
 }
 
 static void
@@ -846,14 +868,13 @@ static int mmci_pio_write(struct mmci_host *host, char *buffer, unsigned int rem
                  */
                 if (variant->sdio &&
                     mmc_card_sdio(host->mmc->card)) {
+                        u32 clk;
                         if (count < 8)
-                                writel(readl(host->base + MMCICLOCK) &
-                                        ~variant->clkreg_enable,
-                                        host->base + MMCICLOCK);
+                                clk = host->clk_reg & ~variant->clkreg_enable;
                         else
-                                writel(readl(host->base + MMCICLOCK) |
-                                        variant->clkreg_enable,
-                                        host->base + MMCICLOCK);
+                                clk = host->clk_reg | variant->clkreg_enable;
+
+                        mmci_write_clkreg(host, clk);
                 }
 
                 /*
@@ -1114,11 +1135,7 @@ static void mmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
         spin_lock_irqsave(&host->lock, flags);
 
         mmci_set_clkreg(host, ios->clock);
-
-        if (host->pwr != pwr) {
-                host->pwr = pwr;
-                writel(pwr, host->base + MMCIPOWER);
-        }
+        mmci_write_pwrreg(host, pwr);
 
         spin_unlock_irqrestore(&host->lock, flags);