[PATCH v2] ARM: OMAP3: PM: fix I/O wakeup and I/O chain clock control detection

On Thu, 6 Oct 2011, Russell King - ARM Linux wrote:

On Thu, Oct 06, 2011 at 01:47:22PM -0600, Paul Walmsley wrote:

quoted

+	if ((omap_rev() == OMAP3430_REV_ES3_1 ||
+	     omap_rev() == OMAP3430_REV_ES3_1_2) ||
+	    cpu_is_omap3630())
+		omap_features |= OMAP3_HAS_IO_CHAIN_CTRL;

	(a || b) || c === a || b || c

IOW, no need for the additional parens.

Thanks; patch updated.

quoted

diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index 7255d9b..a6156bd 100644
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c

@@ -99,31 +99,28 @@ static void omap3_enable_io_chain(void)
 {
 	int timeout = 0;
 
-	if (omap_rev() >= OMAP3430_REV_ES3_1) {
-		omap2_prm_set_mod_reg_bits(OMAP3430_EN_IO_CHAIN_MASK, WKUP_MOD,
-				     PM_WKEN);
-		/* Do a readback to assure write has been done */
-		omap2_prm_read_mod_reg(WKUP_MOD, PM_WKEN);
-
-		while (!(omap2_prm_read_mod_reg(WKUP_MOD, PM_WKEN) &
-			 OMAP3430_ST_IO_CHAIN_MASK)) {
-			timeout++;
-			if (timeout > 1000) {
-				printk(KERN_ERR "Wake up daisy chain "
-				       "activation failed.\n");
-				return;
-			}
-			omap2_prm_set_mod_reg_bits(OMAP3430_ST_IO_CHAIN_MASK,
-					     WKUP_MOD, PM_WKEN);
+	omap2_prm_set_mod_reg_bits(OMAP3430_EN_IO_CHAIN_MASK, WKUP_MOD,
+				   PM_WKEN);
+	/* Do a readback to assure write has been done */
+	omap2_prm_read_mod_reg(WKUP_MOD, PM_WKEN);
+
+	while (!(omap2_prm_read_mod_reg(WKUP_MOD, PM_WKEN) &
+		 OMAP3430_ST_IO_CHAIN_MASK)) {
+		timeout++;
+		if (timeout > 1000) {
+			printk(KERN_ERR "Wake up daisy chain "
+			       "activation failed.\n");
+			return;
 		}
+		omap2_prm_set_mod_reg_bits(OMAP3430_ST_IO_CHAIN_MASK,
+					   WKUP_MOD, PM_WKEN);
 	}

This should've been caught before.  Two things:

1. Do you know how long it takes this to time out?

No, I don't; and I doubt the original author did either.

Really there should be at least a udelay(1) in that code; since as it 
stands right now, there's at least a partial CPU/interconnect/high 
frequency oscillator speed dependency in that loop.

But this patch was intended to be a minimal fix, avoiding code changes 
that are unrelated to the I/O chain feature detection change.  Those lines 
just showed up due to the indentation level change...
 

2. Don't wrap error printks, it prevents them being grepped for.

Thanks; patch updated.


- Paul