ENGR00155981: MX6: Fix crash caused by cpufreq during suspend/resume

Random crashes occur in CPUFREQ code when resuming from suspend.
The root cause is due to freeing and allocating of common data structure
(frequency table) shared among all the CPUs.
Fix the code by ensuring that the common data structure is only
created and deleted once.

Signed-off-by: Ranjani Vaidyanathan <ra5478@freescale.com>

diff --git a/arch/arm/plat-mxc/cpufreq.c b/arch/arm/plat-mxc/cpufreq.c
index 88cfaa63f8eae66b343952f813800733dc0e1ebf..bb2a6c8c99003f770b56123b6b70f86c45db7b7a 100755 (executable)
--- a/arch/arm/plat-mxc/cpufreq.c
+++ b/arch/arm/plat-mxc/cpufreq.c
@@ -207,28 +207,29 @@ static int __devinit mxc_cpufreq_init(struct cpufreq_policy *policy)
        cpu_freq_khz_min = cpu_op_tbl[0].cpu_rate / 1000;
        cpu_freq_khz_max = cpu_op_tbl[0].cpu_rate / 1000;
 
-       imx_freq_table = kmalloc(
-               sizeof(struct cpufreq_frequency_table) * (cpu_op_nr + 1),
-                       GFP_KERNEL);
-       if (!imx_freq_table) {
-               ret = -ENOMEM;
-               goto err1;
-       }
-
-       for (i = 0; i < cpu_op_nr; i++) {
-               imx_freq_table[i].index = i;
-               imx_freq_table[i].frequency = cpu_op_tbl[i].cpu_rate / 1000;
+       if (imx_freq_table == NULL) {
+               imx_freq_table = kmalloc(
+                       sizeof(struct cpufreq_frequency_table) * (cpu_op_nr + 1),
+                               GFP_KERNEL);
+               if (!imx_freq_table) {
+                       ret = -ENOMEM;
+                       goto err1;
+               }
 
-               if ((cpu_op_tbl[i].cpu_rate / 1000) < cpu_freq_khz_min)
-                       cpu_freq_khz_min = cpu_op_tbl[i].cpu_rate / 1000;
+               for (i = 0; i < cpu_op_nr; i++) {
+                       imx_freq_table[i].index = i;
+                       imx_freq_table[i].frequency = cpu_op_tbl[i].cpu_rate / 1000;
 
-               if ((cpu_op_tbl[i].cpu_rate / 1000) > cpu_freq_khz_max)
-                       cpu_freq_khz_max = cpu_op_tbl[i].cpu_rate / 1000;
-       }
+                       if ((cpu_op_tbl[i].cpu_rate / 1000) < cpu_freq_khz_min)
+                               cpu_freq_khz_min = cpu_op_tbl[i].cpu_rate / 1000;
 
-       imx_freq_table[i].index = i;
-       imx_freq_table[i].frequency = CPUFREQ_TABLE_END;
+                       if ((cpu_op_tbl[i].cpu_rate / 1000) > cpu_freq_khz_max)
+                               cpu_freq_khz_max = cpu_op_tbl[i].cpu_rate / 1000;
+               }
 
+               imx_freq_table[i].index = i;
+               imx_freq_table[i].frequency = CPUFREQ_TABLE_END;
+       }
        policy->cur = clk_get_rate(cpu_clk) / 1000;
        policy->min = policy->cpuinfo.min_freq = cpu_freq_khz_min;
        policy->max = policy->cpuinfo.max_freq = cpu_freq_khz_max;
@@ -265,9 +266,11 @@ static int mxc_cpufreq_exit(struct cpufreq_policy *policy)
 {
        cpufreq_frequency_table_put_attr(policy->cpu);
 
-       set_cpu_freq(cpu_freq_khz_max * 1000);
-       clk_put(cpu_clk);
-       kfree(imx_freq_table);
+       if (policy->cpu == 0) {
+               set_cpu_freq(cpu_freq_khz_max * 1000);
+               clk_put(cpu_clk);
+               kfree(imx_freq_table);
+       }
        return 0;
 }