[PATCH] ARM: OMAP AM3517/05: hwmod data: block WFI when EMAC active

[Paul Walmsley]

On Sun, 30 Dec 2012, Paul Walmsley wrote:

> However, for some reason, we don't have an EMAC hwmod -- probably some 
> bug in the data -- so set the flag on the MDIO hwmod data instead.

Mark and I discussed this in private E-mail.  Looks like I managed to 
confuse AM33xx and AM3517 :-(  Here's the updated patch.


- Paul


From: Paul Walmsley <paul at pwsan.com>
Date: Sun, 30 Dec 2012 10:36:36 -0700
Subject: [PATCH] ARM: OMAP AM3517/05: hwmod data: block WFI when EMAC active

According to Mark Greer, on OMAP AM3517/3505 chips, the EMAC is unable
to wake the ARM up from WFI:

    http://www.spinics.net/lists/arm-kernel/msg174734.html

Further troubleshooting was unable to narrow the problem down.  So we
don't have much choice other than to block WFI when the EMAC is active
with the HWMOD_BLOCK_WFI flag.

Based on Mark's original patch.  We're removing the omap_device-based
pm_lats code, so a different approach was needed.

This second version contains some corrections thanks to Mark's review.

Signed-off-by: Paul Walmsley <paul at pwsan.com>
Cc: Mark A. Greer <mgreer at animalcreek.com>
---
 arch/arm/mach-omap2/omap_hwmod_3xxx_data.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
index 8bb2628..7af28b7 100644
--- a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
@@ -3493,7 +3493,13 @@ static struct omap_hwmod am35xx_emac_hwmod = {
 	.name		= "davinci_emac",
 	.mpu_irqs	= am35xx_emac_mpu_irqs,
 	.class		= &am35xx_emac_class,
-	.flags		= HWMOD_NO_IDLEST,
+	/*
+	 * According to Mark Greer, the MPU will not return from WFI
+	 * when the EMAC signals an interrupt.  We're missing an EMAC
+	 * hwmod for some reason, so add the flag to the MDIO instead.
+	 * http://www.spinics.net/lists/arm-kernel/msg174734.html
+	 */
+	.flags		= (HWMOD_NO_IDLEST | HWMOD_BLOCK_WFI),
 };
 
 /* l3_core -> davinci emac interface */
-- 
1.7.10.4