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Remove EL2/EL1 GICv3 register updates 

From Linux 3.17 onwards, the mainline kernel has support for GICv3
systems and if EL3 exists, it only needs to initialise ICC_SRE_EL3.SRE
and ICC_SRE_EL3.Enable to 1. Hence, this patch removes the redundant
updates of ICC_SRE_EL2 and ICC_PMR_EL1.

NOTE: For partner software's which enter kernel in EL1,
ICC_SRE_EL2.Enable and ICC_SRE_EL2.SRE bit needs to be set to 1
in EL2 before jumping to linux.

Change-Id: I09ed47869351b08a3b034735f532bc677eaa6917
This commit is contained in:
Vikram Kanigiri 2015-06-26 10:13:22 +01:00
parent 468f808cb8
commit 889fce4259
1 changed files with 2 additions and 28 deletions
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30
drivers/arm/gic/arm_gic.c
View File

@ -62,7 +62,7 @@ static unsigned int g_num_irqs;
******************************************************************************/
static void gicv3_cpuif_setup(void)
{
unsigned int scr_val, val;
unsigned int val;
uintptr_t base;
/*
@ -93,35 +93,9 @@ static void gicv3_cpuif_setup(void)
while (val & WAKER_CA)
val = gicr_read_waker(base);
/*
* We need to set SCR_EL3.NS in order to see GICv3 non-secure state.
* Restore SCR_EL3.NS again before exit.
*/
scr_val = read_scr();
write_scr(scr_val | SCR_NS_BIT);
isb(); /* ensure NS=1 takes effect before accessing ICC_SRE_EL2 */
/*
* By default EL2 and NS-EL1 software should be able to enable GICv3
* System register access without any configuration at EL3. But it turns
* out that GICC PMR as set in GICv2 mode does not affect GICv3 mode. So
* we need to set it here again. In order to do that we need to enable
* register access. We leave it enabled as it should be fine and might
* prevent problems with later software trying to access GIC System
* Registers.
*/
val = read_icc_sre_el3();
write_icc_sre_el3(val | ICC_SRE_EN | ICC_SRE_SRE);
val = read_icc_sre_el2();
write_icc_sre_el2(val | ICC_SRE_EN | ICC_SRE_SRE);
write_icc_pmr_el1(GIC_PRI_MASK);
isb(); /* commit ICC_* changes before setting NS=0 */
/* Restore SCR_EL3 */
write_scr(scr_val);
isb(); /* ensure NS=0 takes effect immediately */
isb();
}
/*******************************************************************************