ARM: shmobile: Set clock frequency in HZ from OF nodes

shmobile_init_delay() looks for OF "clock-frequency" to determine
the delay which is set by calling shmobile_setup_delay().

Unfortunately this seems to be incorrect in detail as
"clock-frequency" node values are in HZ whereas the frequency
argument to shmobile_setup_delay() is in MHz.

Provide a variant of shmobile_setup_delay() that accepts HZ to
correct this problem.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
(cherry picked from commit f492b81777c93b33afe892b424e022022b5bc297)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

diff --git a/arch/arm/mach-shmobile/timer.c b/arch/arm/mach-shmobile/timer.c
index ccecde9..68bc0b8 100644 (file)
--- a/arch/arm/mach-shmobile/timer.c
+++ b/arch/arm/mach-shmobile/timer.c
@@ -23,6 +23,23 @@
 #include <linux/delay.h>
 #include <linux/of_address.h>
 
+void __init shmobile_setup_delay_hz(unsigned int max_cpu_core_hz,
+                                   unsigned int mult, unsigned int div)
+{
+       /* calculate a worst-case loops-per-jiffy value
+        * based on maximum cpu core hz setting and the
+        * __delay() implementation in arch/arm/lib/delay.S
+        *
+        * this will result in a longer delay than expected
+        * when the cpu core runs on lower frequencies.
+        */
+
+       unsigned int value = HZ * div / mult;
+
+       if (!preset_lpj)
+               preset_lpj = max_cpu_core_hz / value;
+}
+
 void __init shmobile_setup_delay(unsigned int max_cpu_core_mhz,
                                 unsigned int mult, unsigned int div)
 {
@@ -58,12 +75,12 @@ void __init shmobile_init_delay(void)
 
        if (max_freq) {
                if (of_find_compatible_node(NULL, NULL, "arm,cortex-a8"))
-                       shmobile_setup_delay(max_freq, 1, 3);
+                       shmobile_setup_delay_hz(max_freq, 1, 3);
                else if (of_find_compatible_node(NULL, NULL, "arm,cortex-a9"))
-                       shmobile_setup_delay(max_freq, 1, 3);
+                       shmobile_setup_delay_hz(max_freq, 1, 3);
                else if (of_find_compatible_node(NULL, NULL, "arm,cortex-a15"))
                        if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER))
-                               shmobile_setup_delay(max_freq, 2, 4);
+                               shmobile_setup_delay_hz(max_freq, 2, 4);
        }
 }