[U-Boot-Users] [PATCH] Set Rev 2.x 86xx PIC in mixed mode.

[Jon Loeliger]

From: Haiying Wang <haiying.wang at freescale.com>

Prevent false interrupt from hanging Linux as MSR[EE] is set
to enable interrupts by changing the PIC out of the default
pass through mode into mixed mode.

Signed-off-by: Haiying Wang <haiying.wang at freescale.com>
Signed-off-by: Jon Loeliger <jdl at freescale.com>
---
 cpu/mpc86xx/interrupts.c     |   20 ++++++++++++++++++++
 include/asm-ppc/immap_86xx.h |    2 ++
 2 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/cpu/mpc86xx/interrupts.c b/cpu/mpc86xx/interrupts.c
index 1df6cdc..49820bb 100644
--- a/cpu/mpc86xx/interrupts.c
+++ b/cpu/mpc86xx/interrupts.c
@@ -80,6 +80,26 @@ int interrupt_init(void)
 {
 	int ret;
 
+	/*
+	 * The IRQ0 on Rev 2 is pulled high (low in Rev 1.x) to
+	 * implement PEX10 errata.  As INT is active high, it
+	 * will cause core to take 0x500 interrupt.
+	 *
+	 * Due to the PIC's default pass through mode, as soon
+	 * as interrupts are enabled (MSR[EE] = 1), an interrupt
+	 * will be taken and u-boot will hang.  This is due to a
+	 * hardware change (per an errata fix) on new revisions
+	 * of the board with Rev 2.x parts.
+	 *
+	 * Setting the PIC to mixed mode prevents the hang.
+	 */
+	if ((get_svr() & 0xf0) == 0x20) {
+		volatile immap_t *immr = (immap_t *)CFG_IMMR;
+		immr->im_pic.gcr = MPC86xx_PICGCR_RST;
+		while (immr->im_pic.gcr & MPC86xx_PICGCR_RST);
+		immr->im_pic.gcr = MPC86xx_PICGCR_MODE;
+	}
+
 	/* call cpu specific function from $(CPU)/interrupts.c */
 	ret = interrupt_init_cpu(&decrementer_count);
 
diff --git a/include/asm-ppc/immap_86xx.h b/include/asm-ppc/immap_86xx.h
index a5552c4..0e3fc34 100644
--- a/include/asm-ppc/immap_86xx.h
+++ b/include/asm-ppc/immap_86xx.h
@@ -721,6 +721,8 @@ typedef struct ccsr_pic {
 	uint	frr;		/* 0x41000 - Feature Reporting Register */
 	char	res10[28];
 	uint	gcr;		/* 0x41020 - Global Configuration Register */
+#define MPC86xx_PICGCR_RST	0x80000000
+#define MPC86xx_PICGCR_MODE	0x20000000
 	char	res11[92];
 	uint	vir;		/* 0x41080 - Vendor Identification Register */
 	char	res12[12];
-- 
1.4.2.3