OMAP3 clock: fix omap2_clk_wait_ready() for OMAP3430ES2+ DSS

On OMAP3430ES2, DSS has both an initiator standby CM_IDLEST bit, and a
target idle CM_IDLEST bit.  This is a departure from previous silicon,
which only had an initiator standby bit.

This means we need to test the target idle bit after enabling
dss1_alwon_fclk.  Previous clock code has done the wrong thing since ES2
came out: it's either tested the wrong bit, causing

    Clock dss1_alwon_fck failed to enable in 100000 tries

messages, or not tested anything at all, causing crashes during DISPC
initialization with:

    Unhandled fault: external abort on non-linefetch (0x1028)

This patch modifies omap2_clk_wait_ready() to wait for the DSS to become
accessible after dss1_alwon_fclk, dss_l3_iclk, and dss_l4_iclk are enabled.

Thanks to Anand Gadiyar <gadiyar@ti.com> for identifying one of the
problem patches, Koen Kooi <k.kooi@student.utwente.nl> for testing a
previous version of this patch, and Dirk Behme
<dirk.behme@googlemail.com> for review of a previous version.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c
index 57e3217..343477b 100644 (file)
--- a/arch/arm/mach-omap2/clock.c
+++ b/arch/arm/mach-omap2/clock.c
@@ -246,11 +246,27 @@ static void omap2_clk_wait_ready(struct clk *clk)
        }
 
        /* REVISIT: What are the appropriate exclusions for 34XX? */
-       /* OMAP3: ignore DSS-mod clocks */
        if (cpu_is_omap34xx() &&
-           (prcm_mod == OMAP34XX_CM_REGADDR(OMAP3430_DSS_MOD, 0) ||
-            (prcm_mod == OMAP34XX_CM_REGADDR(CORE_MOD, 0) &&
-             clk->enable_bit == OMAP3430_EN_SSI_SHIFT)))
+           prcm_mod == OMAP34XX_CM_REGADDR(OMAP3430_DSS_MOD, 0)) {
+
+               /* 3430ES1 DSS has no target idlest bits */
+               if (is_sil_rev_equal_to(OMAP3430_REV_ES1_0))
+                       return;
+
+               /*
+                * For 3430ES2+ DSS, only wait once (dss1_alwon_fclk,
+                * dss_l3_iclk, dss_l4_iclk) are enabled
+                */
+               if (clk->enable_bit != OMAP3430_EN_DSS1_SHIFT)
+                       return;
+
+       }
+
+       /* REVISIT: SSI has a target idlest bit on OMAP3 */
+       /* REVISIT: This could accidentally exclude other clocks also */
+       if (cpu_is_omap34xx() &&
+           prcm_mod == OMAP34XX_CM_REGADDR(CORE_MOD, 0) &&
+           clk->enable_bit == OMAP3430_EN_SSI_SHIFT)
                return;
 
        /* Check if both functional and interface clocks
@@ -258,6 +274,16 @@ static void omap2_clk_wait_ready(struct clk *clk)
        bit = 1 << clk->enable_bit;
        if (!(__raw_readl((void __iomem *)other_reg) & bit))
                return;
+
+       /*
+        * OMAP3430ES2 DSS target idlest bit is at a different shift than
+        * the corresponding {I,F}CLKEN bits
+        */
+       if (cpu_is_omap34xx() &&
+           prcm_mod == OMAP34XX_CM_REGADDR(OMAP3430_DSS_MOD, 0) &&
+           clk->enable_bit == OMAP3430_EN_DSS1_SHIFT)
+               bit = OMAP3430ES2_ST_DSS_IDLE;
+
        st_reg = ((other_reg & ~0xf0) | 0x20); /* CM_IDLEST* */
 
        omap2_wait_clock_ready((void __iomem *)st_reg, bit, clk->name);

diff --git a/arch/arm/mach-omap2/cm-regbits-34xx.h b/arch/arm/mach-omap2/cm-regbits-34xx.h
index 6ec66f4..946c552 100644 (file)
--- a/arch/arm/mach-omap2/cm-regbits-34xx.h
+++ b/arch/arm/mach-omap2/cm-regbits-34xx.h
@@ -500,7 +500,9 @@
 #define OMAP3430_CM_ICLKEN_DSS_EN_DSS_SHIFT            0
 
 /* CM_IDLEST_DSS */
-#define OMAP3430_ST_DSS                                        (1 << 0)
+#define OMAP3430ES2_ST_DSS_IDLE                                (1 << 1)
+#define OMAP3430ES2_ST_DSS_STDBY                       (1 << 0)
+#define OMAP3430ES1_ST_DSS                             (1 << 0)
 
 /* CM_AUTOIDLE_DSS */
 #define OMAP3430_AUTO_DSS                              (1 << 0)