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@xxxxxx> for identifying one of the
problem patches, Koen Kooi <k.kooi@xxxxxxxxxxxxxxxxxx> for testing a
previous version of this patch, and Dirk Behme
<dirk.behme@xxxxxxxxxxxxxx> for review of a previous version.
Signed-off-by: Paul Walmsley <paul@xxxxxxxxx>
---
arch/arm/mach-omap2/clock.c | 34 +++++++++++++++++++++++++++++----
arch/arm/mach-omap2/cm-regbits-34xx.h | 4 +++-
2 files changed, 33 insertions(+), 5 deletions(-)
diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c
index 57e3217..343477b 100644
--- 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
--- 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)
--
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