ARM: OMAP: Add write memory barriers to OMAP2 clock code

After adjusting clock parameters, OMAP2 CPUs need a memory
barrier to make sure the changes go into effect immediately.
Otherwise bad things will happen if we try to access the
peripheral whose clock is just being enabled.

Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c
index 82643a211008..302d5a796340 100644
--- a/arch/arm/mach-omap2/clock.c
+++ b/arch/arm/mach-omap2/clock.c
@@ -135,6 +135,7 @@ static int _omap2_clk_enable(struct clk * clk)
         regval32 = __raw_readl(clk->enable_reg);
         regval32 |= (1 << clk->enable_bit);
         __raw_writel(regval32, clk->enable_reg);
+        wmb();
 
         return 0;
 }
@@ -168,6 +169,7 @@ static void _omap2_clk_disable(struct clk *clk)
         regval32 = __raw_readl(clk->enable_reg);
         regval32 &= ~(1 << clk->enable_bit);
         __raw_writel(regval32, clk->enable_reg);
+        wmb();
 }
 
 static int omap2_clk_enable(struct clk *clk)
@@ -697,12 +699,14 @@ static int omap2_clk_set_rate(struct clk *clk, unsigned long rate)
                 reg_val = __raw_readl(reg);
                 reg_val &= ~(field_mask << div_off);
                 reg_val |= (field_val << div_off);
-
                 __raw_writel(reg_val, reg);
+                wmb();
                 clk->rate = clk->parent->rate / field_val;
 
-                if (clk->flags & DELAYED_APP)
+                if (clk->flags & DELAYED_APP) {
                         __raw_writel(0x1, (void __iomem *)&PRCM_CLKCFG_CTRL);
+                        wmb();
+                }
                 ret = 0;
         } else if (clk->set_rate != 0)
                 ret = clk->set_rate(clk, rate);
@@ -838,10 +842,12 @@ static int omap2_clk_set_parent(struct clk *clk, struct clk *new_parent)
                 reg_val = __raw_readl(reg) & ~(field_mask << src_off);
                 reg_val |= (field_val << src_off);
                 __raw_writel(reg_val, reg);
+                wmb();
 
-                if (clk->flags & DELAYED_APP)
+                if (clk->flags & DELAYED_APP) {
                         __raw_writel(0x1, (void __iomem *)&PRCM_CLKCFG_CTRL);
-
+                        wmb();
+                }
                 if (clk->usecount > 0)
                         _omap2_clk_enable(clk);