sh: Derive calibrate_delay lpj from clk fwk.

All CPUs must have a sensible cpu_clk definition these days, which we can
safely use for deriving the preset loops_per_jiffy. The only odd one out
is SH-5, which hasn't been hammered in to the framework yet.

Based on the ST patch.

Signed-off-by: Francesco Virlinzi <francesco.virlinzi@st.com>
Signed-off-by: Carl Shaw <carl.shaw@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/arch/sh/kernel/setup.c b/arch/sh/kernel/setup.c
index fc098c8af052..267b344099c0 100644
--- a/arch/sh/kernel/setup.c
+++ b/arch/sh/kernel/setup.c
@@ -27,6 +27,8 @@
 #include <linux/debugfs.h>
 #include <linux/crash_dump.h>
 #include <linux/mmzone.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
 #include <asm/uaccess.h>
 #include <asm/io.h>
 #include <asm/page.h>
@@ -180,6 +182,24 @@ static inline void __init reserve_crashkernel(void)
 {}
 #endif
 
+#ifndef CONFIG_GENERIC_CALIBRATE_DELAY
+void __cpuinit calibrate_delay(void)
+{
+        struct clk *clk = clk_get(NULL, "cpu_clk");
+
+        if (IS_ERR(clk))
+                panic("Need a sane CPU clock definition!");
+
+        loops_per_jiffy = (clk_get_rate(clk) >> 1) / HZ;
+
+        printk(KERN_INFO "Calibrating delay loop (skipped)... "
+                         "%lu.%02lu BogoMIPS PRESET (lpj=%lu)\n",
+                         loops_per_jiffy/(500000/HZ),
+                         (loops_per_jiffy/(5000/HZ)) % 100,
+                         loops_per_jiffy);
+}
+#endif
+
 void __init __add_active_range(unsigned int nid, unsigned long start_pfn,
                                                 unsigned long end_pfn)
 {