powerpc/85xx: implement hardware timebase sync
authorZhao Chenhui <chenhui.zhao@freescale.com>
Fri, 20 Jul 2012 12:42:35 +0000 (20:42 +0800)
committerKumar Gala <galak@kernel.crashing.org>
Wed, 12 Sep 2012 19:57:08 +0000 (14:57 -0500)
Do hardware timebase sync. Firstly, stop all timebases, and transfer the
timebase value of the boot core to the other core. Finally, start all
timebases.

Only apply to dual-core chips, such as MPC8572, P2020, etc.

Signed-off-by: Zhao Chenhui <chenhui.zhao@freescale.com>
Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
arch/powerpc/include/asm/fsl_guts.h
arch/powerpc/platforms/85xx/smp.c

index aa4c488..dd5ba2c 100644 (file)
@@ -48,6 +48,8 @@ struct ccsr_guts {
         __be32  dmuxcr;                /* 0x.0068 - DMA Mux Control Register */
         u8     res06c[0x70 - 0x6c];
        __be32  devdisr;        /* 0x.0070 - Device Disable Control */
+#define CCSR_GUTS_DEVDISR_TB1  0x00001000
+#define CCSR_GUTS_DEVDISR_TB0  0x00004000
        __be32  devdisr2;       /* 0x.0074 - Device Disable Control 2 */
        u8      res078[0x7c - 0x78];
        __be32  pmjcr;          /* 0x.007c - 4 Power Management Jog Control Register */
index 4827709..7ed52a6 100644 (file)
@@ -25,6 +25,7 @@
 #include <asm/mpic.h>
 #include <asm/cacheflush.h>
 #include <asm/dbell.h>
+#include <asm/fsl_guts.h>
 
 #include <sysdev/fsl_soc.h>
 #include <sysdev/mpic.h>
@@ -41,6 +42,64 @@ struct epapr_spin_table {
        u32     pir;
 };
 
+static struct ccsr_guts __iomem *guts;
+static u64 timebase;
+static int tb_req;
+static int tb_valid;
+
+static void mpc85xx_timebase_freeze(int freeze)
+{
+       uint32_t mask;
+
+       mask = CCSR_GUTS_DEVDISR_TB0 | CCSR_GUTS_DEVDISR_TB1;
+       if (freeze)
+               setbits32(&guts->devdisr, mask);
+       else
+               clrbits32(&guts->devdisr, mask);
+
+       in_be32(&guts->devdisr);
+}
+
+static void mpc85xx_give_timebase(void)
+{
+       unsigned long flags;
+
+       local_irq_save(flags);
+
+       while (!tb_req)
+               barrier();
+       tb_req = 0;
+
+       mpc85xx_timebase_freeze(1);
+       timebase = get_tb();
+       mb();
+       tb_valid = 1;
+
+       while (tb_valid)
+               barrier();
+
+       mpc85xx_timebase_freeze(0);
+
+       local_irq_restore(flags);
+}
+
+static void mpc85xx_take_timebase(void)
+{
+       unsigned long flags;
+
+       local_irq_save(flags);
+
+       tb_req = 1;
+       while (!tb_valid)
+               barrier();
+
+       set_tb(timebase >> 32, timebase & 0xffffffff);
+       isync();
+       tb_valid = 0;
+
+       local_irq_restore(flags);
+}
+
 static int __init
 smp_85xx_kick_cpu(int nr)
 {
@@ -228,6 +287,16 @@ smp_85xx_setup_cpu(int cpu_nr)
                doorbell_setup_this_cpu();
 }
 
+static const struct of_device_id mpc85xx_smp_guts_ids[] = {
+       { .compatible = "fsl,mpc8572-guts", },
+       { .compatible = "fsl,p1020-guts", },
+       { .compatible = "fsl,p1021-guts", },
+       { .compatible = "fsl,p1022-guts", },
+       { .compatible = "fsl,p1023-guts", },
+       { .compatible = "fsl,p2020-guts", },
+       {},
+};
+
 void __init mpc85xx_smp_init(void)
 {
        struct device_node *np;
@@ -249,6 +318,19 @@ void __init mpc85xx_smp_init(void)
                smp_85xx_ops.cause_ipi = doorbell_cause_ipi;
        }
 
+       np = of_find_matching_node(NULL, mpc85xx_smp_guts_ids);
+       if (np) {
+               guts = of_iomap(np, 0);
+               of_node_put(np);
+               if (!guts) {
+                       pr_err("%s: Could not map guts node address\n",
+                                                               __func__);
+                       return;
+               }
+               smp_85xx_ops.give_timebase = mpc85xx_give_timebase;
+               smp_85xx_ops.take_timebase = mpc85xx_take_timebase;
+       }
+
        smp_ops = &smp_85xx_ops;
 
 #ifdef CONFIG_KEXEC