Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6

[linux.git] / arch / arm / mach-imx / cpufreq.c

diff --git a/arch/arm/mach-imx/cpufreq.c b/arch/arm/mach-imx/cpufreq.c
index ac5f99895660fa3cf5ab3d4a374329d48bd7946a..7e70e0b0b9890a1757a65f21f7ba2b1df468ff38 100644 (file)
--- a/arch/arm/mach-imx/cpufreq.c
+++ b/arch/arm/mach-imx/cpufreq.c
@@ -50,6 +50,7 @@
 #define CR_920T_ASYNC_MODE     0xC0000000
 
 static u32 mpctl0_at_boot;
+static u32 bclk_div_at_boot;
 
 static void imx_set_async_mode(void)
 {
@@ -82,13 +83,13 @@ static void imx_set_mpctl0(u32 mpctl0)
  * imx_compute_mpctl - compute new PLL parameters
  * @new_mpctl: pointer to location assigned by new PLL control register value
  * @cur_mpctl: current PLL control register parameters
+ * @f_ref:     reference source frequency Hz
  * @freq:      required frequency in Hz
  * @relation:  is one of %CPUFREQ_RELATION_L (supremum)
  *             and %CPUFREQ_RELATION_H (infimum)
  */
-long imx_compute_mpctl(u32 *new_mpctl, u32 cur_mpctl, unsigned long freq, int relation)
+long imx_compute_mpctl(u32 *new_mpctl, u32 cur_mpctl, u32 f_ref, unsigned long freq, int relation)
 {
-        u32 f_ref = (CSCR & CSCR_SYSTEM_SEL) ? 16000000 : (CLK32 * 512);
         u32 mfi;
         u32 mfn;
         u32 mfd;
@@ -182,7 +183,18 @@ static int imx_set_target(struct cpufreq_policy *policy,
        unsigned long flags;
        long freq;
        long sysclk;
-       unsigned int bclk_div = 1;
+       unsigned int bclk_div = bclk_div_at_boot;
+
+       /*
+        * Some governors do not respects CPU and policy lower limits
+        * which leads to bad things (division by zero etc), ensure
+        * that such things do not happen.
+        */
+       if(target_freq < policy->cpuinfo.min_freq)
+               target_freq = policy->cpuinfo.min_freq;
+
+       if(target_freq < policy->min)
+               target_freq = policy->min;
 
        freq = target_freq * 1000;
 
@@ -191,8 +203,8 @@ static int imx_set_target(struct cpufreq_policy *policy,
 
        sysclk = imx_get_system_clk();
 
-       if (freq > sysclk + 1000000) {
-               freq = imx_compute_mpctl(&mpctl0, mpctl0_at_boot, freq, relation);
+       if (freq > sysclk / bclk_div_at_boot + 1000000) {
+               freq = imx_compute_mpctl(&mpctl0, mpctl0_at_boot, CLK32 * 512, freq, relation);
                if (freq < 0) {
                        printk(KERN_WARNING "imx: target frequency %ld Hz cannot be set\n", freq);
                        return -EINVAL;
@@ -206,6 +218,8 @@ static int imx_set_target(struct cpufreq_policy *policy,
 
                        if(bclk_div > 16)
                                bclk_div = 16;
+                       if(bclk_div < bclk_div_at_boot)
+                               bclk_div = bclk_div_at_boot;
                }
                freq = (sysclk + bclk_div / 2) / bclk_div;
        }
@@ -258,7 +272,8 @@ static int __init imx_cpufreq_driver_init(struct cpufreq_policy *policy)
        policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
        policy->cpuinfo.min_freq = 8000;
        policy->cpuinfo.max_freq = 200000;
-       policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+        /* Manual states, that PLL stabilizes in two CLK32 periods */
+       policy->cpuinfo.transition_latency = 4 * 1000000000LL / CLK32;
        return 0;
 }
 
@@ -273,7 +288,7 @@ static struct cpufreq_driver imx_driver = {
 
 static int __init imx_cpufreq_init(void)
 {
-
+       bclk_div_at_boot = __mfld2val(CSCR_BCLK_DIV, CSCR) + 1;
        mpctl0_at_boot = 0;
 
        if((CSCR & CSCR_MPEN) &&