Blackfin arch: rewrite get_sclk()/get_vco()
[linux-2.6.git] / arch / blackfin / kernel / setup.c
index 20d04a1bc86154d6c3a16ce69126cc3981b0cecd..b2a811347b655070472857cac98e6f782c692a78 100644 (file)
@@ -956,17 +956,18 @@ static int __init early_init_clkin_hz(char *buf)
 early_param("clkin_hz=", early_init_clkin_hz);
 
 /* Get the voltage input multiplier */
-static u_long cached_vco_pll_ctl, cached_vco;
 static u_long get_vco(void)
 {
-       u_long msel;
+       static u_long cached_vco;
+       u_long msel, pll_ctl;
 
-       u_long pll_ctl = bfin_read_PLL_CTL();
-       if (pll_ctl == cached_vco_pll_ctl)
+       /* The assumption here is that VCO never changes at runtime.
+        * If, someday, we support that, then we'll have to change this.
+        */
+       if (cached_vco)
                return cached_vco;
-       else
-               cached_vco_pll_ctl = pll_ctl;
 
+       pll_ctl = bfin_read_PLL_CTL();
        msel = (pll_ctl >> 9) & 0x3F;
        if (0 == msel)
                msel = 64;
@@ -978,9 +979,9 @@ static u_long get_vco(void)
 }
 
 /* Get the Core clock */
-static u_long cached_cclk_pll_div, cached_cclk;
 u_long get_cclk(void)
 {
+       static u_long cached_cclk_pll_div, cached_cclk;
        u_long csel, ssel;
 
        if (bfin_read_PLL_STAT() & 0x1)
@@ -1003,21 +1004,21 @@ u_long get_cclk(void)
 EXPORT_SYMBOL(get_cclk);
 
 /* Get the System clock */
-static u_long cached_sclk_pll_div, cached_sclk;
 u_long get_sclk(void)
 {
+       static u_long cached_sclk;
        u_long ssel;
 
+       /* The assumption here is that SCLK never changes at runtime.
+        * If, someday, we support that, then we'll have to change this.
+        */
+       if (cached_sclk)
+               return cached_sclk;
+
        if (bfin_read_PLL_STAT() & 0x1)
                return get_clkin_hz();
 
-       ssel = bfin_read_PLL_DIV();
-       if (ssel == cached_sclk_pll_div)
-               return cached_sclk;
-       else
-               cached_sclk_pll_div = ssel;
-
-       ssel &= 0xf;
+       ssel = bfin_read_PLL_DIV() & 0xf;
        if (0 == ssel) {
                printk(KERN_WARNING "Invalid System Clock\n");
                ssel = 1;