GIC-600: Fix power up sequence
Arm's GIC-600 features a Power Register (GICR_PWRR),
which needs to be programmed to enable redistributor
operation. Section 3.6.1 in the GIC-600 TRM describes
the power-up and power-down sequence in pseudo code,
which deviates from the current TF-A implementation
in drivers/arm/gic/v3/gic600.c.
For powering on a redistributor, the pseudo code suggests
to loop over the whole sequence (check for transition,
write request bit) instead of just looping over the
ready bit read as TF-A does in gic600_pwr_on().
This patch fixes GIC-600 power up sequence according
to the TRM.
Change-Id: I445c480e96ba356b69a2d8e5308ffe6c0a97f45b
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
diff --git a/drivers/arm/gic/v3/gic600.c b/drivers/arm/gic/v3/gic600.c
index 9cb2ab2..59652da 100644
--- a/drivers/arm/gic/v3/gic600.c
+++ b/drivers/arm/gic/v3/gic600.c
@@ -1,14 +1,14 @@
/*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2019, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
/*
- * Driver for GIC600-specific features. This driver only overrides APIs that are
- * different to those generic ones in GICv3 driver.
+ * Driver for GIC-600 specific features. This driver only overrides
+ * APIs that are different to those generic ones in GICv3 driver.
*
- * GIC600 supports independently power-gating redistributor interface.
+ * GIC-600 supports independently power-gating redistributor interface.
*/
#include <assert.h>
@@ -18,22 +18,28 @@
#include "gicv3_private.h"
-/* GIC600-specific register offsets */
+/* GIC-600 specific register offsets */
#define GICR_PWRR 0x24
/* GICR_PWRR fields */
#define PWRR_RDPD_SHIFT 0
+#define PWRR_RDAG_SHIFT 1
#define PWRR_RDGPD_SHIFT 2
#define PWRR_RDGPO_SHIFT 3
+#define PWRR_RDPD (1 << PWRR_RDPD_SHIFT)
+#define PWRR_RDAG (1 << PWRR_RDAG_SHIFT)
#define PWRR_RDGPD (1 << PWRR_RDGPD_SHIFT)
#define PWRR_RDGPO (1 << PWRR_RDGPO_SHIFT)
-/* Values to write to GICR_PWRR register to power redistributor */
+/*
+ * Values to write to GICR_PWRR register to power redistributor
+ * for operating through the core (GICR_PWRR.RDAG = 0)
+ */
#define PWRR_ON (0 << PWRR_RDPD_SHIFT)
#define PWRR_OFF (1 << PWRR_RDPD_SHIFT)
-/* GIC600-specific accessor functions */
+/* GIC-600 specific accessor functions */
static void gicr_write_pwrr(uintptr_t base, unsigned int val)
{
mmio_write_32(base + GICR_PWRR, val);
@@ -44,39 +50,46 @@
return mmio_read_32(base + GICR_PWRR);
}
-static int gicr_group_powering_down(uint32_t pwrr)
+static void gicr_wait_group_not_in_transit(uintptr_t base)
{
- /*
- * Whether the redistributor group power down operation is in transit:
- * i.e. it's intending to, but not finished yet.
- */
- return ((pwrr & PWRR_RDGPD) && !(pwrr & PWRR_RDGPO));
+ /* Check group not transitioning: RDGPD == RDGPO */
+ while (((gicr_read_pwrr(base) & PWRR_RDGPD) >> PWRR_RDGPD_SHIFT) !=
+ ((gicr_read_pwrr(base) & PWRR_RDGPO) >> PWRR_RDGPO_SHIFT))
+ ;
}
static void gic600_pwr_on(uintptr_t base)
{
- /* Power on redistributor */
- gicr_write_pwrr(base, PWRR_ON);
+ do { /* Wait until group not transitioning */
+ gicr_wait_group_not_in_transit(base);
- /* Wait until the power on state is reflected */
- while (gicr_read_pwrr(base) & PWRR_RDGPO)
- ;
+ /* Power on redistributor */
+ gicr_write_pwrr(base, PWRR_ON);
+
+ /*
+ * Wait until the power on state is reflected.
+ * If RDPD == 0 then powered on.
+ */
+ } while ((gicr_read_pwrr(base) & PWRR_RDPD) != PWRR_ON);
}
static void gic600_pwr_off(uintptr_t base)
{
+ /* Wait until group not transitioning */
+ gicr_wait_group_not_in_transit(base);
+
/* Power off redistributor */
gicr_write_pwrr(base, PWRR_OFF);
/*
* If this is the last man, turning this redistributor frame off will
- * result in the group itself being powered off. In that case, wait as
- * long as it's in transition, or has aborted the transition altogether
- * for any reason.
+ * result in the group itself being powered off and RDGPD = 1.
+ * In that case, wait as long as it's in transition, or has aborted
+ * the transition altogether for any reason.
*/
- if (gicr_read_pwrr(base) & PWRR_RDGPD) {
- while (gicr_group_powering_down(gicr_read_pwrr(base)))
- ;
+ if ((gicr_read_pwrr(base) & PWRR_RDGPD) != 0) {
+ /* Wait until group not transitioning */
+ gicr_wait_group_not_in_transit(base);
}
}
@@ -91,7 +104,7 @@
}
/*
- * Power off GIC600 redistributor
+ * Power off GIC-600 redistributor
*/
void gicv3_rdistif_off(unsigned int proc_num)
{
@@ -109,7 +122,7 @@
}
/*
- * Power on GIC600 redistributor
+ * Power on GIC-600 redistributor
*/
void gicv3_rdistif_on(unsigned int proc_num)
{