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--- a/arch/mips/ralink/mt7621.c
+++ b/arch/mips/ralink/mt7621.c
@@ -7,6 +7,7 @@
#include <linux/kernel.h>
#include <linux/init.h>
+#include <linux/jiffies.h>
#include <asm/mipsregs.h>
#include <asm/smp-ops.h>
@@ -14,6 +15,7 @@
#include <asm/mach-ralink/ralink_regs.h>
#include <asm/mach-ralink/mt7621.h>
#include <asm/mips-boards/launch.h>
+#include <asm/delay.h>
#include <pinmux.h>
@@ -175,6 +177,58 @@ bool plat_cpu_core_present(int core)
return true;
}
+#define LPS_PREC 8
+/*
+* Re-calibration lpj(loop-per-jiffy).
+* (derived from kernel/calibrate.c)
+*/
+static int udelay_recal(void)
+{
+ unsigned int i, lpj = 0;
+ unsigned long ticks, loopbit;
+ int lps_precision = LPS_PREC;
+
+ lpj = (1<<12);
+
+ while ((lpj <<= 1) != 0) {
+ /* wait for "start of" clock tick */
+ ticks = jiffies;
+ while (ticks == jiffies)
+ /* nothing */;
+
+ /* Go .. */
+ ticks = jiffies;
+ __delay(lpj);
+ ticks = jiffies - ticks;
+ if (ticks)
+ break;
+ }
+
+ /*
+ * Do a binary approximation to get lpj set to
+ * equal one clock (up to lps_precision bits)
+ */
+ lpj >>= 1;
+ loopbit = lpj;
+ while (lps_precision-- && (loopbit >>= 1)) {
+ lpj |= loopbit;
+ ticks = jiffies;
+ while (ticks == jiffies)
+ /* nothing */;
+ ticks = jiffies;
+ __delay(lpj);
+ if (jiffies != ticks) /* longer than 1 tick */
+ lpj &= ~loopbit;
+ }
+ printk(KERN_INFO "%d CPUs re-calibrate udelay(lpj = %d)\n", NR_CPUS, lpj);
+
+ for(i=0; i< NR_CPUS; i++)
+ cpu_data[i].udelay_val = lpj;
+
+ return 0;
+}
+device_initcall(udelay_recal);
+
void prom_soc_init(struct ralink_soc_info *soc_info)
{
void __iomem *sysc = (void __iomem *) KSEG1ADDR(MT7621_SYSC_BASE);
--- a/arch/mips/ralink/Kconfig
+++ b/arch/mips/ralink/Kconfig
@@ -58,6 +58,7 @@ choice
select CLKSRC_MIPS_GIC
select HAVE_PCI if PCI_MT7621
select WEAK_REORDERING_BEYOND_LLSC
+ select GENERIC_CLOCKEVENTS_BROADCAST
endchoice
choice
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