[ARM] S3C64XX: Add ARM clock

Add ARM clock to provide 'arm' from the APLL to the ARM core.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>

2 files changed, 76 insertions, 2 deletions

diff --git a/arch/arm/plat-s3c64xx/include/plat/s3c6400.h b/arch/arm/plat-s3c64xx/include/plat/s3c6400.h
index e12296666d46..11f2e1e119b0 100644
--- a/arch/arm/plat-s3c64xx/include/plat/s3c6400.h
+++ b/arch/arm/plat-s3c64xx/include/plat/s3c6400.h
@@ -15,7 +15,7 @@
 /* Common init code for S3C6400 related SoCs */
 
 extern void s3c6400_common_init_uarts(struct s3c2410_uartcfg *cfg, int no);
-extern void s3c6400_register_clocks(void);
+extern void s3c6400_register_clocks(unsigned armclk_divlimit);
 extern void s3c6400_setup_clocks(void);
 
 #ifdef CONFIG_CPU_S3C6400
diff --git a/arch/arm/plat-s3c64xx/s3c6400-clock.c b/arch/arm/plat-s3c64xx/s3c6400-clock.c
index 96fa9ea4d5bc..1debc1f9f987 100644
--- a/arch/arm/plat-s3c64xx/s3c6400-clock.c
+++ b/arch/arm/plat-s3c64xx/s3c6400-clock.c
@@ -133,6 +133,65 @@ static struct clksrc_clk clk_mout_mpll = {
         .sources        = &clk_src_mpll,
 };
 
+static unsigned int armclk_mask;
+
+static unsigned long s3c64xx_clk_arm_get_rate(struct clk *clk)
+{
+        unsigned long rate = clk_get_rate(clk->parent);
+        u32 clkdiv;
+
+        /* divisor mask starts at bit0, so no need to shift */
+        clkdiv = __raw_readl(S3C_CLK_DIV0) & armclk_mask;
+
+        return rate / (clkdiv + 1);
+}
+
+static unsigned long s3c64xx_clk_arm_round_rate(struct clk *clk,
+                                                unsigned long rate)
+{
+        unsigned long parent = clk_get_rate(clk->parent);
+        u32 div;
+
+        if (parent < rate)
+                return rate;
+
+        div = (parent / rate) - 1;
+        if (div > armclk_mask)
+                div = armclk_mask;
+
+        return parent / (div + 1);
+}
+
+static int s3c64xx_clk_arm_set_rate(struct clk *clk, unsigned long rate)
+{
+        unsigned long parent = clk_get_rate(clk->parent);
+        u32 div;
+        u32 val;
+
+        if (rate < parent / (armclk_mask + 1))
+                return -EINVAL;
+
+        rate = clk_round_rate(clk, rate);
+        div = clk_get_rate(clk->parent) / rate;
+
+        val = __raw_readl(S3C_CLK_DIV0);
+        val &= armclk_mask;
+        val |= (div - 1);
+        __raw_writel(val, S3C_CLK_DIV0);
+
+        return 0;
+
+}
+
+static struct clk clk_arm = {
+        .name           = "armclk",
+        .id             = -1,
+        .parent         = &clk_mout_apll.clk,
+        .get_rate       = s3c64xx_clk_arm_get_rate,
+        .set_rate       = s3c64xx_clk_arm_set_rate,
+        .round_rate     = s3c64xx_clk_arm_round_rate,
+};
+
 static unsigned long s3c64xx_clk_doutmpll_get_rate(struct clk *clk)
 {
         unsigned long rate = clk_get_rate(clk->parent);
@@ -665,14 +724,29 @@ static struct clk *clks[] __initdata = {
         &clk_audio1.clk,
         &clk_irda.clk,
         &clk_camif.clk,
+        &clk_arm,
 };
 
-void __init s3c6400_register_clocks(void)
+/**
+ * s3c6400_register_clocks - register clocks for s3c6400 and above
+ * @armclk_divlimit: Divisor mask for ARMCLK
+ *
+ * Register the clocks for the S3C6400 and above SoC range, such
+ * as ARMCLK and the clocks which have divider chains attached.
+ *
+ * This call does not setup the clocks, which is left to the
+ * s3c6400_setup_clocks() call which may be needed by the cpufreq
+ * or resume code to re-set the clocks if the bootloader has changed
+ * them.
+ */
+void __init s3c6400_register_clocks(unsigned armclk_divlimit)
 {
         struct clk *clkp;
         int ret;
         int ptr;
 
+        armclk_mask = armclk_divlimit;
+
         for (ptr = 0; ptr < ARRAY_SIZE(clks); ptr++) {
                 clkp = clks[ptr];
                 ret = s3c24xx_register_clock(clkp);