powerpc/85xx: implement hardware timebase sync

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>

2 files changed, 84 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/fsl_guts.h b/arch/powerpc/include/asm/fsl_guts.h
index aa4c488589ce..dd5ba2c22771 100644
--- a/arch/powerpc/include/asm/fsl_guts.h
+++ b/arch/powerpc/include/asm/fsl_guts.h
@@ -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 */
diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c
index 4827709996ce..7ed52a604a13 100644
--- a/arch/powerpc/platforms/85xx/smp.c
+++ b/arch/powerpc/platforms/85xx/smp.c
@@ -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