* [PATCH v2 1/2] ARM: shmobile: wait for MSTP clock status to toggle, when enabling it
@ 2013-06-13 8:58 Guennadi Liakhovetski
2013-06-13 16:39 ` Laurent Pinchart
0 siblings, 1 reply; 2+ messages in thread
From: Guennadi Liakhovetski @ 2013-06-13 8:58 UTC (permalink / raw)
To: linux-sh
On r-/sh-mobile SoCs MSTP clocks are used by the runtime PM to dynamically
enable and disable peripheral clocks. To make sure the clock has really
started we have to read back its status register until it confirms success.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
---
v2:
1. removed "const" reom read accessors to fix compiler warnings
2. added a "(void __iomem *)" cast, as suggested by Laurent
drivers/sh/clk/cpg.c | 38 ++++++++++++++++++++++++++++++++++++++
include/linux/sh_clk.h | 29 +++++++++++++++++------------
2 files changed, 55 insertions(+), 12 deletions(-)
diff --git a/drivers/sh/clk/cpg.c b/drivers/sh/clk/cpg.c
index 1ebe67c..87de622 100644
--- a/drivers/sh/clk/cpg.c
+++ b/drivers/sh/clk/cpg.c
@@ -36,9 +36,47 @@ static void sh_clk_write(int value, struct clk *clk)
iowrite32(value, clk->mapped_reg);
}
+static unsigned int r8(void __iomem *addr)
+{
+ return ioread8(addr);
+}
+
+static unsigned int r16(void __iomem *addr)
+{
+ return ioread16(addr);
+}
+
+static unsigned int r32(void __iomem *addr)
+{
+ return ioread32(addr);
+}
+
static int sh_clk_mstp_enable(struct clk *clk)
{
sh_clk_write(sh_clk_read(clk) & ~(1 << clk->enable_bit), clk);
+ if (clk->status_reg) {
+ unsigned int (*read)(void __iomem *addr);
+ int i;
+ void __iomem *mapped_status = (phys_addr_t)clk->status_reg -
+ (phys_addr_t)clk->enable_reg + clk->mapped_reg;
+
+ if (clk->flags & CLK_ENABLE_REG_8BIT)
+ read = r8;
+ else if (clk->flags & CLK_ENABLE_REG_16BIT)
+ read = r16;
+ else
+ read = r32;
+
+ for (i = 1000;
+ (read(mapped_status) & (1 << clk->enable_bit)) && i;
+ i--)
+ cpu_relax();
+ if (!i) {
+ pr_err("cpg: failed to enable %p[%d]\n",
+ clk->enable_reg, clk->enable_bit);
+ return -ETIMEDOUT;
+ }
+ }
return 0;
}
diff --git a/include/linux/sh_clk.h b/include/linux/sh_clk.h
index 60c7239..affc8d8 100644
--- a/include/linux/sh_clk.h
+++ b/include/linux/sh_clk.h
@@ -52,6 +52,7 @@ struct clk {
unsigned long flags;
void __iomem *enable_reg;
+ void __iomem *status_reg;
unsigned int enable_bit;
void __iomem *mapped_reg;
@@ -116,22 +117,26 @@ long clk_round_parent(struct clk *clk, unsigned long target,
unsigned long *best_freq, unsigned long *parent_freq,
unsigned int div_min, unsigned int div_max);
-#define SH_CLK_MSTP(_parent, _enable_reg, _enable_bit, _flags) \
-{ \
- .parent = _parent, \
- .enable_reg = (void __iomem *)_enable_reg, \
- .enable_bit = _enable_bit, \
- .flags = _flags, \
+#define SH_CLK_MSTP(_parent, _enable_reg, _enable_bit, _status_reg, _flags) \
+{ \
+ .parent = _parent, \
+ .enable_reg = (void __iomem *)_enable_reg, \
+ .enable_bit = _enable_bit, \
+ .status_reg = (void __iomem *)_status_reg, \
+ .flags = _flags, \
}
-#define SH_CLK_MSTP32(_p, _r, _b, _f) \
- SH_CLK_MSTP(_p, _r, _b, _f | CLK_ENABLE_REG_32BIT)
+#define SH_CLK_MSTP32(_p, _r, _b, _f) \
+ SH_CLK_MSTP(_p, _r, _b, 0, _f | CLK_ENABLE_REG_32BIT)
-#define SH_CLK_MSTP16(_p, _r, _b, _f) \
- SH_CLK_MSTP(_p, _r, _b, _f | CLK_ENABLE_REG_16BIT)
+#define SH_CLK_MSTP32_STS(_p, _r, _b, _s, _f) \
+ SH_CLK_MSTP(_p, _r, _b, _s, _f | CLK_ENABLE_REG_32BIT)
-#define SH_CLK_MSTP8(_p, _r, _b, _f) \
- SH_CLK_MSTP(_p, _r, _b, _f | CLK_ENABLE_REG_8BIT)
+#define SH_CLK_MSTP16(_p, _r, _b, _f) \
+ SH_CLK_MSTP(_p, _r, _b, 0, _f | CLK_ENABLE_REG_16BIT)
+
+#define SH_CLK_MSTP8(_p, _r, _b, _f) \
+ SH_CLK_MSTP(_p, _r, _b, 0, _f | CLK_ENABLE_REG_8BIT)
int sh_clk_mstp_register(struct clk *clks, int nr);
--
1.7.2.5
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH v2 1/2] ARM: shmobile: wait for MSTP clock status to toggle, when enabling it
2013-06-13 8:58 [PATCH v2 1/2] ARM: shmobile: wait for MSTP clock status to toggle, when enabling it Guennadi Liakhovetski
@ 2013-06-13 16:39 ` Laurent Pinchart
0 siblings, 0 replies; 2+ messages in thread
From: Laurent Pinchart @ 2013-06-13 16:39 UTC (permalink / raw)
To: linux-sh
Hi Guennadi,
Thanks for the patch.
On Thursday 13 June 2013 10:58:41 Guennadi Liakhovetski wrote:
> On r-/sh-mobile SoCs MSTP clocks are used by the runtime PM to dynamically
> enable and disable peripheral clocks. To make sure the clock has really
> started we have to read back its status register until it confirms success.
>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
> ---
>
> v2:
> 1. removed "const" reom read accessors to fix compiler warnings
> 2. added a "(void __iomem *)" cast, as suggested by Laurent
After a quick review I'm wondering if it wouldn't make more sense to drop the
cast and change the status_reg field type to phys_addr_t. The enable_reg field
should probably be changed accordingly as well.
> drivers/sh/clk/cpg.c | 38 ++++++++++++++++++++++++++++++++++++++
> include/linux/sh_clk.h | 29 +++++++++++++++++------------
> 2 files changed, 55 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/sh/clk/cpg.c b/drivers/sh/clk/cpg.c
> index 1ebe67c..87de622 100644
> --- a/drivers/sh/clk/cpg.c
> +++ b/drivers/sh/clk/cpg.c
> @@ -36,9 +36,47 @@ static void sh_clk_write(int value, struct clk *clk)
> iowrite32(value, clk->mapped_reg);
> }
>
> +static unsigned int r8(void __iomem *addr)
> +{
> + return ioread8(addr);
> +}
> +
> +static unsigned int r16(void __iomem *addr)
> +{
> + return ioread16(addr);
> +}
> +
> +static unsigned int r32(void __iomem *addr)
> +{
> + return ioread32(addr);
> +}
> +
> static int sh_clk_mstp_enable(struct clk *clk)
> {
> sh_clk_write(sh_clk_read(clk) & ~(1 << clk->enable_bit), clk);
> + if (clk->status_reg) {
> + unsigned int (*read)(void __iomem *addr);
> + int i;
> + void __iomem *mapped_status = (phys_addr_t)clk->status_reg -
> + (phys_addr_t)clk->enable_reg + clk->mapped_reg;
> +
> + if (clk->flags & CLK_ENABLE_REG_8BIT)
> + read = r8;
> + else if (clk->flags & CLK_ENABLE_REG_16BIT)
> + read = r16;
> + else
> + read = r32;
> +
> + for (i = 1000;
> + (read(mapped_status) & (1 << clk->enable_bit)) && i;
> + i--)
> + cpu_relax();
> + if (!i) {
> + pr_err("cpg: failed to enable %p[%d]\n",
> + clk->enable_reg, clk->enable_bit);
> + return -ETIMEDOUT;
> + }
> + }
> return 0;
> }
>
> diff --git a/include/linux/sh_clk.h b/include/linux/sh_clk.h
> index 60c7239..affc8d8 100644
> --- a/include/linux/sh_clk.h
> +++ b/include/linux/sh_clk.h
> @@ -52,6 +52,7 @@ struct clk {
> unsigned long flags;
>
> void __iomem *enable_reg;
> + void __iomem *status_reg;
> unsigned int enable_bit;
> void __iomem *mapped_reg;
>
> @@ -116,22 +117,26 @@ long clk_round_parent(struct clk *clk, unsigned long
> target, unsigned long *best_freq, unsigned long *parent_freq,
> unsigned int div_min, unsigned int div_max);
>
> -#define SH_CLK_MSTP(_parent, _enable_reg, _enable_bit, _flags) \
> -{ \
> - .parent = _parent, \
> - .enable_reg = (void __iomem *)_enable_reg, \
> - .enable_bit = _enable_bit, \
> - .flags = _flags, \
> +#define SH_CLK_MSTP(_parent, _enable_reg, _enable_bit, _status_reg,
> _flags) \ +{ \
> + .parent = _parent, \
> + .enable_reg = (void __iomem *)_enable_reg, \
> + .enable_bit = _enable_bit, \
> + .status_reg = (void __iomem *)_status_reg, \
> + .flags = _flags, \
> }
>
> -#define SH_CLK_MSTP32(_p, _r, _b, _f) \
> - SH_CLK_MSTP(_p, _r, _b, _f | CLK_ENABLE_REG_32BIT)
> +#define SH_CLK_MSTP32(_p, _r, _b, _f) \
> + SH_CLK_MSTP(_p, _r, _b, 0, _f | CLK_ENABLE_REG_32BIT)
>
> -#define SH_CLK_MSTP16(_p, _r, _b, _f) \
> - SH_CLK_MSTP(_p, _r, _b, _f | CLK_ENABLE_REG_16BIT)
> +#define SH_CLK_MSTP32_STS(_p, _r, _b, _s, _f) \
> + SH_CLK_MSTP(_p, _r, _b, _s, _f | CLK_ENABLE_REG_32BIT)
>
> -#define SH_CLK_MSTP8(_p, _r, _b, _f) \
> - SH_CLK_MSTP(_p, _r, _b, _f | CLK_ENABLE_REG_8BIT)
> +#define SH_CLK_MSTP16(_p, _r, _b, _f) \
> + SH_CLK_MSTP(_p, _r, _b, 0, _f | CLK_ENABLE_REG_16BIT)
> +
> +#define SH_CLK_MSTP8(_p, _r, _b, _f) \
> + SH_CLK_MSTP(_p, _r, _b, 0, _f | CLK_ENABLE_REG_8BIT)
>
> int sh_clk_mstp_register(struct clk *clks, int nr);
--
Regards,
Laurent Pinchart
^ permalink raw reply [flat|nested] 2+ messages in thread
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2013-06-13 8:58 [PATCH v2 1/2] ARM: shmobile: wait for MSTP clock status to toggle, when enabling it Guennadi Liakhovetski
2013-06-13 16:39 ` Laurent Pinchart
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