[POWERPC] cell: add shadow registers for pmd_reg

Many of the registers in the performance monitoring unit are write-only.
We need to save a "shadow" copy when we write to those registers so we
can retrieve the values if we need them later.

The new cbe_pmd_shadow_regs structure is added to the cbe_regs_map structure
so we have the appropriate per-node copies of these shadow values.

Signed-off-by: Kevin Corry <kevcorry@us.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 52 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/cell/cbe_regs.c b/arch/powerpc/platforms/cell/cbe_regs.c
index 5e3e0e925e4e..5a91b75c2f01 100644
--- a/arch/powerpc/platforms/cell/cbe_regs.c
+++ b/arch/powerpc/platforms/cell/cbe_regs.c
@@ -30,6 +30,7 @@ static struct cbe_regs_map
         struct cbe_pmd_regs __iomem *pmd_regs;
         struct cbe_iic_regs __iomem *iic_regs;
         struct cbe_mic_tm_regs __iomem *mic_tm_regs;
+        struct cbe_pmd_shadow_regs pmd_shadow_regs;
 } cbe_regs_maps[MAX_CBE];
 static int cbe_regs_map_count;
 
@@ -80,6 +81,22 @@ struct cbe_pmd_regs __iomem *cbe_get_cpu_pmd_regs(int cpu)
 }
 EXPORT_SYMBOL_GPL(cbe_get_cpu_pmd_regs);
 
+struct cbe_pmd_shadow_regs *cbe_get_pmd_shadow_regs(struct device_node *np)
+{
+        struct cbe_regs_map *map = cbe_find_map(np);
+        if (map == NULL)
+                return NULL;
+        return &map->pmd_shadow_regs;
+}
+
+struct cbe_pmd_shadow_regs *cbe_get_cpu_pmd_shadow_regs(int cpu)
+{
+        struct cbe_regs_map *map = cbe_thread_map[cpu].regs;
+        if (map == NULL)
+                return NULL;
+        return &map->pmd_shadow_regs;
+}
+
 struct cbe_iic_regs __iomem *cbe_get_iic_regs(struct device_node *np)
 {
         struct cbe_regs_map *map = cbe_find_map(np);
diff --git a/arch/powerpc/platforms/cell/cbe_regs.h b/arch/powerpc/platforms/cell/cbe_regs.h
index 02bdbc1cd6e7..d352f110ef9c 100644
--- a/arch/powerpc/platforms/cell/cbe_regs.h
+++ b/arch/powerpc/platforms/cell/cbe_regs.h
@@ -121,6 +121,41 @@ extern struct cbe_pmd_regs __iomem *cbe_get_pmd_regs(struct device_node *np);
 extern struct cbe_pmd_regs __iomem *cbe_get_cpu_pmd_regs(int cpu);
 
 /*
+ * PMU shadow registers
+ *
+ * Many of the registers in the performance monitoring unit are write-only,
+ * so we need to save a copy of what we write to those registers.
+ *
+ * The actual data counters are read/write. However, writing to the counters
+ * only takes effect if the PMU is enabled. Otherwise the value is stored in
+ * a hardware latch until the next time the PMU is enabled. So we save a copy
+ * of the counter values if we need to read them back while the PMU is
+ * disabled. The counter_value_in_latch field is a bitmap indicating which
+ * counters currently have a value waiting to be written.
+ */
+
+#define NR_PHYS_CTRS    4
+#define NR_CTRS         (NR_PHYS_CTRS * 2)
+
+struct cbe_pmd_shadow_regs {
+        u32 group_control;
+        u32 debug_bus_control;
+        u32 trace_address;
+        u32 ext_tr_timer;
+        u32 pm_status;
+        u32 pm_control;
+        u32 pm_interval;
+        u32 pm_start_stop;
+        u32 pm07_control[NR_CTRS];
+
+        u32 pm_ctr[NR_PHYS_CTRS];
+        u32 counter_value_in_latch;
+};
+
+extern struct cbe_pmd_shadow_regs *cbe_get_pmd_shadow_regs(struct device_node *np);
+extern struct cbe_pmd_shadow_regs *cbe_get_cpu_pmd_shadow_regs(int cpu);
+
+/*
  *
  * IIC unit register definitions
  *