ARM: mxs: Use a proper timeout mechanism

Introduce a function for checking the busy bits of CLKCTRL register that
uses a proper timeout mechanism.

Remove parts of code that use busy loops and replace them with the
mxs_clkctrl_timeout() function.

Tested on a mx28evk by performing audio playback.

Suggested-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

diff --git a/arch/arm/mach-mxs/clock-mx23.c b/arch/arm/mach-mxs/clock-mx23.c
index e12e112..293958b 100644 (file)
--- a/arch/arm/mach-mxs/clock-mx23.c
+++ b/arch/arm/mach-mxs/clock-mx23.c
@@ -223,7 +223,6 @@ static int cpu_clk_set_rate(struct clk *clk, unsigned long rate)
 {
        u32 reg, bm_busy, div_max, d, f, div, frac;
        unsigned long diff, parent_rate, calc_rate;
-       int i;
 
        parent_rate = clk_get_rate(clk->parent);
 
@@ -275,14 +274,7 @@ static int cpu_clk_set_rate(struct clk *clk, unsigned long rate)
        reg |= div << BP_CLKCTRL_CPU_DIV_CPU;
        __raw_writel(reg, CLKCTRL_BASE_ADDR + HW_CLKCTRL_CPU);
 
-       for (i = 10000; i; i--)
-               if (!(__raw_readl(CLKCTRL_BASE_ADDR +
-                                       HW_CLKCTRL_CPU) & bm_busy))
-                       break;
-       if (!i) {
-               pr_err("%s: divider writing timeout\n", __func__);
-               return -ETIMEDOUT;
-       }
+       mxs_clkctrl_timeout(HW_CLKCTRL_CPU, bm_busy);
 
        return 0;
 }
@@ -292,7 +284,6 @@ static int name##_set_rate(struct clk *clk, unsigned long rate)             \
 {                                                                      \
        u32 reg, div_max, div;                                          \
        unsigned long parent_rate;                                      \
-       int i;                                                          \
                                                                        \
        parent_rate = clk_get_rate(clk->parent);                        \
        div_max = BM_CLKCTRL_##dr##_DIV >> BP_CLKCTRL_##dr##_DIV;       \
@@ -310,15 +301,7 @@ static int name##_set_rate(struct clk *clk, unsigned long rate)            \
        }                                                               \
        __raw_writel(reg, CLKCTRL_BASE_ADDR + HW_CLKCTRL_##dr);         \
                                                                        \
-       for (i = 10000; i; i--)                                         \
-               if (!(__raw_readl(CLKCTRL_BASE_ADDR +                   \
-                       HW_CLKCTRL_##dr) & BM_CLKCTRL_##dr##_BUSY))     \
-                       break;                                          \
-       if (!i) {                                                       \
-               pr_err("%s: divider writing timeout\n", __func__);      \
-               return -ETIMEDOUT;                                      \
-       }                                                               \
-                                                                       \
+       mxs_clkctrl_timeout(HW_CLKCTRL_##dr, BM_CLKCTRL_##dr##_BUSY);   \
        return 0;                                                       \
 }
 
@@ -461,7 +444,7 @@ static struct clk_lookup lookups[] = {
 static int clk_misc_init(void)
 {
        u32 reg;
-       int i;
+       int ret;
 
        /* Fix up parent per register setting */
        reg = __raw_readl(CLKCTRL_BASE_ADDR + HW_CLKCTRL_CLKSEQ);
@@ -510,14 +493,7 @@ static int clk_misc_init(void)
        reg |= 3 << BP_CLKCTRL_HBUS_DIV;
        __raw_writel(reg, CLKCTRL_BASE_ADDR + HW_CLKCTRL_HBUS);
 
-       for (i = 10000; i; i--)
-               if (!(__raw_readl(CLKCTRL_BASE_ADDR +
-                       HW_CLKCTRL_HBUS) & BM_CLKCTRL_HBUS_BUSY))
-                       break;
-       if (!i) {
-               pr_err("%s: divider writing timeout\n", __func__);
-               return -ETIMEDOUT;
-       }
+       ret = mxs_clkctrl_timeout(HW_CLKCTRL_HBUS, BM_CLKCTRL_HBUS_BUSY);
 
        /* Gate off cpu clock in WFI for power saving */
        __raw_writel(BM_CLKCTRL_CPU_INTERRUPT_WAIT,
@@ -532,7 +508,7 @@ static int clk_misc_init(void)
        reg |= 30 << BP_CLKCTRL_FRAC_IOFRAC;
        __raw_writel(reg, CLKCTRL_BASE_ADDR + HW_CLKCTRL_FRAC);
 
-       return 0;
+       return ret;
 }
 
 int __init mx23_clocks_init(void)

diff --git a/arch/arm/mach-mxs/clock-mx28.c b/arch/arm/mach-mxs/clock-mx28.c
index 54d82a4..22ad12f 100644 (file)
--- a/arch/arm/mach-mxs/clock-mx28.c
+++ b/arch/arm/mach-mxs/clock-mx28.c
@@ -322,7 +322,6 @@ static int name##_set_rate(struct clk *clk, unsigned long rate)             \
 {                                                                      \
        u32 reg, bm_busy, div_max, d, f, div, frac;                     \
        unsigned long diff, parent_rate, calc_rate;                     \
-       int i;                                                          \
                                                                        \
        div_max = BM_CLKCTRL_##dr##_DIV >> BP_CLKCTRL_##dr##_DIV;       \
        bm_busy = BM_CLKCTRL_##dr##_BUSY;                               \
@@ -396,16 +395,7 @@ static int name##_set_rate(struct clk *clk, unsigned long rate)            \
        }                                                               \
        __raw_writel(reg, CLKCTRL_BASE_ADDR + HW_CLKCTRL_##dr);         \
                                                                        \
-       for (i = 10000; i; i--)                                         \
-               if (!(__raw_readl(CLKCTRL_BASE_ADDR +                   \
-                       HW_CLKCTRL_##dr) & bm_busy))                    \
-                       break;                                          \
-       if (!i) {                                                       \
-               pr_err("%s: divider writing timeout\n", __func__);      \
-               return -ETIMEDOUT;                                      \
-       }                                                               \
-                                                                       \
-       return 0;                                                       \
+       return mxs_clkctrl_timeout(HW_CLKCTRL_##dr, bm_busy);           \
 }
 
 _CLK_SET_RATE(cpu_clk, CPU, FRAC0, CPU)
@@ -421,7 +411,6 @@ static int name##_set_rate(struct clk *clk, unsigned long rate)             \
 {                                                                      \
        u32 reg, div_max, div;                                          \
        unsigned long parent_rate;                                      \
-       int i;                                                          \
                                                                        \
        parent_rate = clk_get_rate(clk->parent);                        \
        div_max = BM_CLKCTRL_##dr##_DIV >> BP_CLKCTRL_##dr##_DIV;       \
@@ -439,16 +428,7 @@ static int name##_set_rate(struct clk *clk, unsigned long rate)            \
        }                                                               \
        __raw_writel(reg, CLKCTRL_BASE_ADDR + HW_CLKCTRL_##dr);         \
                                                                        \
-       for (i = 10000; i; i--)                                         \
-               if (!(__raw_readl(CLKCTRL_BASE_ADDR +                   \
-                       HW_CLKCTRL_##dr) & BM_CLKCTRL_##dr##_BUSY))     \
-                       break;                                          \
-       if (!i) {                                                       \
-               pr_err("%s: divider writing timeout\n", __func__);      \
-               return -ETIMEDOUT;                                      \
-       }                                                               \
-                                                                       \
-       return 0;                                                       \
+       return mxs_clkctrl_timeout(HW_CLKCTRL_##dr, BM_CLKCTRL_##dr##_BUSY);\
 }
 
 _CLK_SET_RATE1(xbus_clk, XBUS)
@@ -461,7 +441,6 @@ static int name##_set_rate(struct clk *clk, unsigned long rate)             \
        u32 reg;                                                        \
        u64 lrate;                                                      \
        unsigned long parent_rate;                                      \
-       int i;                                                          \
                                                                        \
        parent_rate = clk_get_rate(clk->parent);                        \
        if (rate > parent_rate)                                         \
@@ -483,16 +462,7 @@ static int name##_set_rate(struct clk *clk, unsigned long rate)            \
        }                                                               \
        __raw_writel(reg, CLKCTRL_BASE_ADDR + HW_CLKCTRL_##rs);         \
                                                                        \
-       for (i = 10000; i; i--)                                         \
-               if (!(__raw_readl(CLKCTRL_BASE_ADDR +                   \
-                       HW_CLKCTRL_##rs) & BM_CLKCTRL_##rs##_BUSY))     \
-                       break;                                          \
-       if (!i) {                                                       \
-               pr_err("%s: divider writing timeout\n", __func__);      \
-               return -ETIMEDOUT;                                      \
-       }                                                               \
-                                                                       \
-       return 0;                                                       \
+       return mxs_clkctrl_timeout(HW_CLKCTRL_##rs, BM_CLKCTRL_##rs##_BUSY);\
 }
 
 _CLK_SET_RATE_SAIF(saif0_clk, SAIF0)
@@ -682,7 +652,7 @@ static struct clk_lookup lookups[] = {
 static int clk_misc_init(void)
 {
        u32 reg;
-       int i;
+       int ret;
 
        /* Fix up parent per register setting */
        reg = __raw_readl(CLKCTRL_BASE_ADDR + HW_CLKCTRL_CLKSEQ);
@@ -762,14 +732,7 @@ static int clk_misc_init(void)
        reg |= 3 << BP_CLKCTRL_HBUS_DIV;
        __raw_writel(reg, CLKCTRL_BASE_ADDR + HW_CLKCTRL_HBUS);
 
-       for (i = 10000; i; i--)
-               if (!(__raw_readl(CLKCTRL_BASE_ADDR +
-                       HW_CLKCTRL_HBUS) & BM_CLKCTRL_HBUS_ASM_BUSY))
-                       break;
-       if (!i) {
-               pr_err("%s: divider writing timeout\n", __func__);
-               return -ETIMEDOUT;
-       }
+       ret = mxs_clkctrl_timeout(HW_CLKCTRL_HBUS, BM_CLKCTRL_HBUS_ASM_BUSY);
 
        /* Gate off cpu clock in WFI for power saving */
        __raw_writel(BM_CLKCTRL_CPU_INTERRUPT_WAIT,
@@ -796,7 +759,7 @@ static int clk_misc_init(void)
        reg |= 30 << BP_CLKCTRL_FRAC0_IO0FRAC;
        __raw_writel(reg, CLKCTRL_BASE_ADDR + HW_CLKCTRL_FRAC0);
 
-       return 0;
+       return ret;
 }
 
 int __init mx28_clocks_init(void)

diff --git a/arch/arm/mach-mxs/include/mach/common.h b/arch/arm/mach-mxs/include/mach/common.h
index e1237ab..c50c3ea 100644 (file)
--- a/arch/arm/mach-mxs/include/mach/common.h
+++ b/arch/arm/mach-mxs/include/mach/common.h
@@ -31,4 +31,6 @@ extern void mx28_init_irq(void);
 
 extern void icoll_init_irq(void);
 
+extern int mxs_clkctrl_timeout(unsigned int reg_offset, unsigned int mask);
+
 #endif /* __MACH_MXS_COMMON_H__ */

diff --git a/arch/arm/mach-mxs/system.c b/arch/arm/mach-mxs/system.c
index 54f91ad..7aa5ac5 100644 (file)
--- a/arch/arm/mach-mxs/system.c
+++ b/arch/arm/mach-mxs/system.c
@@ -37,6 +37,8 @@
 #define MXS_MODULE_CLKGATE             (1 << 30)
 #define MXS_MODULE_SFTRST              (1 << 31)
 
+#define CLKCTRL_TIMEOUT                10      /* 10 ms */
+
 static void __iomem *mxs_clkctrl_reset_addr;
 
 /*
@@ -137,3 +139,17 @@ error:
        return -ETIMEDOUT;
 }
 EXPORT_SYMBOL(mxs_reset_block);
+
+int mxs_clkctrl_timeout(unsigned int reg_offset, unsigned int mask)
+{
+       unsigned long timeout = jiffies + msecs_to_jiffies(CLKCTRL_TIMEOUT);
+       while (readl_relaxed(MXS_IO_ADDRESS(MXS_CLKCTRL_BASE_ADDR)
+                                               + reg_offset) & mask) {
+               if (time_after(jiffies, timeout)) {
+                       pr_err("Timeout at CLKCTRL + 0x%x\n", reg_offset);
+                       return -ETIMEDOUT;
+               }
+       }
+
+       return 0;
+}