c7ca224299
For a long time the mt7621 uses a fixed cpu clock which causes a problem if the cpu frequency is not 880MHz. This patch fixes the cpu clock calculation and adds the cpu/bus clkdev which will be used in dts. Signed-off-by: Weijie Gao <hackpascal@gmail.com>
87 lines
1.9 KiB
Diff
87 lines
1.9 KiB
Diff
--- a/arch/mips/ralink/mt7621.c
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+++ b/arch/mips/ralink/mt7621.c
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@@ -9,6 +9,7 @@
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#include <linux/kernel.h>
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#include <linux/init.h>
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+#include <linux/jiffies.h>
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#include <asm/mipsregs.h>
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#include <asm/smp-ops.h>
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@@ -16,6 +16,7 @@
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#include <asm/mach-ralink/ralink_regs.h>
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#include <asm/mach-ralink/mt7621.h>
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#include <asm/mips-boards/launch.h>
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+#include <asm/delay.h>
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#include <pinmux.h>
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@@ -177,6 +178,58 @@ bool plat_cpu_core_present(int core)
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return true;
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}
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+#define LPS_PREC 8
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+/*
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+* Re-calibration lpj(loop-per-jiffy).
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+* (derived from kernel/calibrate.c)
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+*/
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+static int udelay_recal(void)
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+{
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+ unsigned int i, lpj = 0;
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+ unsigned long ticks, loopbit;
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+ int lps_precision = LPS_PREC;
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+
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+ lpj = (1<<12);
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+
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+ while ((lpj <<= 1) != 0) {
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+ /* wait for "start of" clock tick */
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+ ticks = jiffies;
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+ while (ticks == jiffies)
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+ /* nothing */;
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+
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+ /* Go .. */
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+ ticks = jiffies;
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+ __delay(lpj);
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+ ticks = jiffies - ticks;
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+ if (ticks)
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+ break;
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+ }
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+
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+ /*
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+ * Do a binary approximation to get lpj set to
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+ * equal one clock (up to lps_precision bits)
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+ */
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+ lpj >>= 1;
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+ loopbit = lpj;
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+ while (lps_precision-- && (loopbit >>= 1)) {
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+ lpj |= loopbit;
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+ ticks = jiffies;
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+ while (ticks == jiffies)
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+ /* nothing */;
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+ ticks = jiffies;
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+ __delay(lpj);
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+ if (jiffies != ticks) /* longer than 1 tick */
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+ lpj &= ~loopbit;
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+ }
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+ printk(KERN_INFO "%d CPUs re-calibrate udelay(lpj = %d)\n", NR_CPUS, lpj);
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+
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+ for(i=0; i< NR_CPUS; i++)
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+ cpu_data[i].udelay_val = lpj;
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+
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+ return 0;
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+}
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+device_initcall(udelay_recal);
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+
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void prom_soc_init(struct ralink_soc_info *soc_info)
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{
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void __iomem *sysc = (void __iomem *) KSEG1ADDR(MT7621_SYSC_BASE);
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--- a/arch/mips/ralink/Kconfig
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+++ b/arch/mips/ralink/Kconfig
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@@ -58,6 +58,7 @@ choice
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select CLKSRC_MIPS_GIC
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select HW_HAS_PCI
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select WEAK_REORDERING_BEYOND_LLSC
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+ select GENERIC_CLOCKEVENTS_BROADCAST
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endchoice
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choice
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