ARM: shmobile: R-Car: Improve documentation

Add more SYSC register documentation.
Use definitions instead of hardcoded numbers.
Comment important operations.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

diff --git a/arch/arm/mach-shmobile/pm-rcar.c b/arch/arm/mach-shmobile/pm-rcar.c
index 00022ee56f80dc3075e59a6a93e05acb09a38c80..56ea82a851cb96f72e83a99aef1c82bd3bdc907e 100644 (file)
--- a/arch/arm/mach-shmobile/pm-rcar.c
+++ b/arch/arm/mach-shmobile/pm-rcar.c
@@ -15,21 +15,35 @@
 #include <asm/io.h>
 #include "pm-rcar.h"
 
-/* SYSC */
-#define SYSCSR 0x00
-#define SYSCISR 0x04
-#define SYSCISCR 0x08
+/* SYSC Common */
+#define SYSCSR                 0x00    /* SYSC Status Register */
+#define SYSCISR                        0x04    /* Interrupt Status Register */
+#define SYSCISCR               0x08    /* Interrupt Status Clear Register */
+#define SYSCIER                        0x0c    /* Interrupt Enable Register */
+#define SYSCIMR                        0x10    /* Interrupt Mask Register */
 
-#define PWRSR_OFFS 0x00
-#define PWROFFCR_OFFS 0x04
-#define PWRONCR_OFFS 0x0c
-#define PWRER_OFFS 0x14
+/* SYSC Status Register */
+#define SYSCSR_PONENB          1       /* Ready for power resume requests */
+#define SYSCSR_POFFENB         0       /* Ready for power shutoff requests */
 
-#define SYSCSR_RETRIES 100
-#define SYSCSR_DELAY_US 1
+/*
+ * Power Control Register Offsets inside the register block for each domain
+ * Note: The "CR" registers for ARM cores exist on H1 only
+ *       Use WFI to power off, CPG/APMU to resume ARM cores on R-Car Gen2
+ */
+#define PWRSR_OFFS             0x00    /* Power Status Register */
+#define PWROFFCR_OFFS          0x04    /* Power Shutoff Control Register */
+#define PWROFFSR_OFFS          0x08    /* Power Shutoff Status Register */
+#define PWRONCR_OFFS           0x0c    /* Power Resume Control Register */
+#define PWRONSR_OFFS           0x10    /* Power Resume Status Register */
+#define PWRER_OFFS             0x14    /* Power Shutoff/Resume Error */
+
+
+#define SYSCSR_RETRIES         100
+#define SYSCSR_DELAY_US                1
 
-#define SYSCISR_RETRIES 1000
-#define SYSCISR_DELAY_US 1
+#define SYSCISR_RETRIES                1000
+#define SYSCISR_DELAY_US       1
 
 static void __iomem *rcar_sysc_base;
 static DEFINE_SPINLOCK(rcar_sysc_lock); /* SMP CPUs + I/O devices */
@@ -39,6 +53,7 @@ static int rcar_sysc_pwr_on_off(struct rcar_sysc_ch *sysc_ch,
 {
        int k;
 
+       /* Wait until SYSC is ready to accept a power request */
        for (k = 0; k < SYSCSR_RETRIES; k++) {
                if (ioread32(rcar_sysc_base + SYSCSR) & (1 << sr_bit))
                        break;
@@ -48,6 +63,7 @@ static int rcar_sysc_pwr_on_off(struct rcar_sysc_ch *sysc_ch,
        if (k == SYSCSR_RETRIES)
                return -EAGAIN;
 
+       /* Submit power shutoff or power resume request */
        iowrite32(1 << sysc_ch->chan_bit,
                  rcar_sysc_base + sysc_ch->chan_offs + reg_offs);
 
@@ -56,12 +72,12 @@ static int rcar_sysc_pwr_on_off(struct rcar_sysc_ch *sysc_ch,
 
 static int rcar_sysc_pwr_off(struct rcar_sysc_ch *sysc_ch)
 {
-       return rcar_sysc_pwr_on_off(sysc_ch, 0, PWROFFCR_OFFS);
+       return rcar_sysc_pwr_on_off(sysc_ch, SYSCSR_POFFENB, PWROFFCR_OFFS);
 }
 
 static int rcar_sysc_pwr_on(struct rcar_sysc_ch *sysc_ch)
 {
-       return rcar_sysc_pwr_on_off(sysc_ch, 1, PWRONCR_OFFS);
+       return rcar_sysc_pwr_on_off(sysc_ch, SYSCSR_PONENB, PWRONCR_OFFS);
 }
 
 static int rcar_sysc_update(struct rcar_sysc_ch *sysc_ch,
@@ -78,6 +94,7 @@ static int rcar_sysc_update(struct rcar_sysc_ch *sysc_ch,
 
        iowrite32(isr_mask, rcar_sysc_base + SYSCISCR);
 
+       /* Submit power shutoff or resume request until it was accepted */
        do {
                ret = on_off_fn(sysc_ch);
                if (ret)
@@ -87,6 +104,7 @@ static int rcar_sysc_update(struct rcar_sysc_ch *sysc_ch,
                                  sysc_ch->chan_offs + PWRER_OFFS);
        } while (status & chan_mask);
 
+       /* Wait until the power shutoff or resume request has completed * */
        for (k = 0; k < SYSCISR_RETRIES; k++) {
                if (ioread32(rcar_sysc_base + SYSCISR) & isr_mask)
                        break;