clocksource: sh_cmt: 32-bit control register support

Add support for CMT hardware with 32-bit control and counter
registers, as found on r8a73a4 and r8a7790. To use the CMT
with 32-bit hardware a second I/O memory resource needs to
point out the CMSTR register and it needs to be 32 bit wide.

Signed-off-by: Magnus Damm <damm@opensource.se>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

1 files changed, 36 insertions, 14 deletions

diff --git a/drivers/clocksource/sh_cmt.c b/drivers/clocksource/sh_cmt.c
index 08d0c418c94a..0965e9848b3d 100644
--- a/drivers/clocksource/sh_cmt.c
+++ b/drivers/clocksource/sh_cmt.c
@@ -37,6 +37,7 @@
 
 struct sh_cmt_priv {
         void __iomem *mapbase;
+        void __iomem *mapbase_str;
         struct clk *clk;
         unsigned long width; /* 16 or 32 bit version of hardware block */
         unsigned long overflow_bit;
@@ -79,6 +80,12 @@ struct sh_cmt_priv {
  * CMCSR 0xffca0060 16-bit
  * CMCNT 0xffca0064 32-bit
  * CMCOR 0xffca0068 32-bit
+ *
+ * "32-bit counter and 32-bit control" as found on r8a73a4 and r8a7790:
+ * CMSTR 0xffca0500 32-bit
+ * CMCSR 0xffca0510 32-bit
+ * CMCNT 0xffca0514 32-bit
+ * CMCOR 0xffca0518 32-bit
  */
 
 static unsigned long sh_cmt_read16(void __iomem *base, unsigned long offs)
@@ -109,9 +116,7 @@ static void sh_cmt_write32(void __iomem *base, unsigned long offs,
 
 static inline unsigned long sh_cmt_read_cmstr(struct sh_cmt_priv *p)
 {
-        struct sh_timer_config *cfg = p->pdev->dev.platform_data;
-
-        return p->read_control(p->mapbase - cfg->channel_offset, 0);
+        return p->read_control(p->mapbase_str, 0);
 }
 
 static inline unsigned long sh_cmt_read_cmcsr(struct sh_cmt_priv *p)
@@ -127,9 +132,7 @@ static inline unsigned long sh_cmt_read_cmcnt(struct sh_cmt_priv *p)
 static inline void sh_cmt_write_cmstr(struct sh_cmt_priv *p,
                                       unsigned long value)
 {
-        struct sh_timer_config *cfg = p->pdev->dev.platform_data;
-
-        p->write_control(p->mapbase - cfg->channel_offset, 0, value);
+        p->write_control(p->mapbase_str, 0, value);
 }
 
 static inline void sh_cmt_write_cmcsr(struct sh_cmt_priv *p,
@@ -676,7 +679,7 @@ static int sh_cmt_register(struct sh_cmt_priv *p, char *name,
 static int sh_cmt_setup(struct sh_cmt_priv *p, struct platform_device *pdev)
 {
         struct sh_timer_config *cfg = pdev->dev.platform_data;
-        struct resource *res;
+        struct resource *res, *res2;
         int irq, ret;
         ret = -ENXIO;
 
@@ -694,6 +697,9 @@ static int sh_cmt_setup(struct sh_cmt_priv *p, struct platform_device *pdev)
                 goto err0;
         }
 
+        /* optional resource for the shared timer start/stop register */
+        res2 = platform_get_resource(p->pdev, IORESOURCE_MEM, 1);
+
         irq = platform_get_irq(p->pdev, 0);
         if (irq < 0) {
                 dev_err(&p->pdev->dev, "failed to get irq\n");
@@ -707,6 +713,15 @@ static int sh_cmt_setup(struct sh_cmt_priv *p, struct platform_device *pdev)
                 goto err0;
         }
 
+        /* map second resource for CMSTR */
+        p->mapbase_str = ioremap_nocache(res2 ? res2->start :
+                                         res->start - cfg->channel_offset,
+                                         res2 ? resource_size(res2) : 2);
+        if (p->mapbase_str == NULL) {
+                dev_err(&p->pdev->dev, "failed to remap I/O second memory\n");
+                goto err1;
+        }
+
         /* request irq using setup_irq() (too early for request_irq()) */
         p->irqaction.name = dev_name(&p->pdev->dev);
         p->irqaction.handler = sh_cmt_interrupt;
@@ -719,11 +734,17 @@ static int sh_cmt_setup(struct sh_cmt_priv *p, struct platform_device *pdev)
         if (IS_ERR(p->clk)) {
                 dev_err(&p->pdev->dev, "cannot get clock\n");
                 ret = PTR_ERR(p->clk);
-                goto err1;
+                goto err2;
         }
 
-        p->read_control = sh_cmt_read16;
-        p->write_control = sh_cmt_write16;
+        if (res2 && (resource_size(res2) == 4)) {
+                /* assume both CMSTR and CMCSR to be 32-bit */
+                p->read_control = sh_cmt_read32;
+                p->write_control = sh_cmt_write32;
+        } else {
+                p->read_control = sh_cmt_read16;
+                p->write_control = sh_cmt_write16;
+        }
 
         if (resource_size(res) == 6) {
                 p->width = 16;
@@ -752,22 +773,23 @@ static int sh_cmt_setup(struct sh_cmt_priv *p, struct platform_device *pdev)
                               cfg->clocksource_rating);
         if (ret) {
                 dev_err(&p->pdev->dev, "registration failed\n");
-                goto err2;
+                goto err3;
         }
         p->cs_enabled = false;
 
         ret = setup_irq(irq, &p->irqaction);
         if (ret) {
                 dev_err(&p->pdev->dev, "failed to request irq %d\n", irq);
-                goto err2;
+                goto err3;
         }
 
         platform_set_drvdata(pdev, p);
 
         return 0;
-err2:
+err3:
         clk_put(p->clk);
-
+err2:
+        iounmap(p->mapbase_str);
 err1:
         iounmap(p->mapbase);
 err0: