Patch "ARM: AM33xx: PRM: Remove am33xx_pwrdm_read_prev_pwrst function" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

ARM: AM33xx: PRM: Remove am33xx_pwrdm_read_prev_pwrst function

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm-am33xx-prm-remove-am33xx_pwrdm_read_prev_pwrst-function.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Keerthy <[email protected]>
Date: Fri, 10 Nov 2017 16:56:52 +0530
Subject: ARM: AM33xx: PRM: Remove am33xx_pwrdm_read_prev_pwrst function

From: Keerthy <[email protected]>

[ Upstream commit b6d6af7226465b6d11eac09d0be2ab78a4a9eb62 ]

Referring TRM Am335X series:
http://www.ti.com/lit/ug/spruh73p/spruh73p.pdf

The LastPowerStateEntered bitfield is present only for PM_CEFUSE domain. This is not present in any of the other power domains. Hence remove the generic am33xx_pwrdm_read_prev_pwrst hook which wrongly reads the reserved bit fields for all the other power domains.

Reading the reserved bits leads to wrongly interpreting the low power transitions for various power domains that do not have the LastPowerStateEntered field. The pm debug counters values are wrong currently as we are incrementing them based on the reserved bits.

---
 arch/arm/mach-omap2/prm33xx.c |   12 ------------
 1 file changed, 12 deletions(-)

@@ -176,17 +176,6 @@ static int am33xx_pwrdm_read_pwrst(struc
 	return v;
 }
 
-static int am33xx_pwrdm_read_prev_pwrst(struct powerdomain *pwrdm)
-{
-	u32 v;
-
-	v = am33xx_prm_read_reg(pwrdm->prcm_offs, pwrdm->pwrstst_offs);
-	v &= AM33XX_LASTPOWERSTATEENTERED_MASK;
-	v >>= AM33XX_LASTPOWERSTATEENTERED_SHIFT;
-
-	return v;
-}
-
 static int am33xx_pwrdm_set_lowpwrstchange(struct powerdomain *pwrdm)
 {
 	am33xx_prm_rmw_reg_bits(AM33XX_LOWPOWERSTATECHANGE_MASK,

@@ -357,7 +346,6 @@ struct pwrdm_ops am33xx_pwrdm_operations
 	.pwrdm_set_next_pwrst		= am33xx_pwrdm_set_next_pwrst,
 	.pwrdm_read_next_pwrst		= am33xx_pwrdm_read_next_pwrst,
 	.pwrdm_read_pwrst		= am33xx_pwrdm_read_pwrst,
-	.pwrdm_read_prev_pwrst		= am33xx_pwrdm_read_prev_pwrst,
 	.pwrdm_set_logic_retst		= am33xx_pwrdm_set_logic_retst,
 	.pwrdm_read_logic_pwrst		= am33xx_pwrdm_read_logic_pwrst,
 	.pwrdm_read_logic_retst		= am33xx_pwrdm_read_logic_retst,

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/arm-am33xx-prm-remove-am33xx_pwrdm_read_prev_pwrst-function.patch