85xx: Introduce determine_mp_bootpg() helper.

Match determine_mp_bootpg() that was added for 86xx.  We need this to
address a bug introduced in v2009.03 with 86xx MP booting.  We have to
make sure to reserve the region of memory used for the MP bootpg() so
other u-boot code doesn't use it.

Also added a comment about how cpu_reset() is dealing w/an errata on
early 85xx MP HW.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

cpu/mpc85xx/fdt.c

@@ -39,13 +39,8 @@ void ft_fixup_cpu(void *blob, u64 memory_limit)
 {
 	int off;
 	ulong spin_tbl_addr = get_spin_addr();
-	u32 bootpg, id = get_my_id();
-
-	/* if we have 4G or more of memory, put the boot page at 4Gb-4k */
-	if ((u64)gd->ram_size > 0xfffff000)
-		bootpg = 0xfffff000;
-	else
-		bootpg = gd->ram_size - 4096;
+	u32 bootpg = determine_mp_bootpg();
+	u32 id = get_my_id();
 
 	off = fdt_node_offset_by_prop_value(blob, -1, "device_type", "cpu", 4);
 	while (off != -FDT_ERR_NOTFOUND) {

cpu/mpc85xx/mp.c

@@ -38,6 +38,7 @@ int cpu_reset(int nr)
 {
 	volatile ccsr_pic_t *pic = (void *)(CONFIG_SYS_MPC85xx_PIC_ADDR);
 	out_be32(&pic->pir, 1 << nr);
+	/* the dummy read works around an errata on early 85xx MP PICs */
 	(void)in_be32(&pic->pir);
 	out_be32(&pic->pir, 0x0);
 
@@ -112,6 +113,15 @@ int cpu_release(int nr, int argc, char *argv[])
 	return 0;
 }
 
+u32 determine_mp_bootpg(void)
+{
+	/* if we have 4G or more of memory, put the boot page at 4Gb-4k */
+	if ((u64)gd->ram_size > 0xfffff000)
+		return (0xfffff000);
+
+	return (gd->ram_size - 4096);
+}
+
 ulong get_spin_addr(void)
 {
 	extern ulong __secondary_start_page;
@@ -188,13 +198,7 @@ static void pq3_mp_up(unsigned long bootpg)
 
 void cpu_mp_lmb_reserve(struct lmb *lmb)
 {
-	u32 bootpg;
-
-	/* if we have 4G or more of memory, put the boot page at 4Gb-4k */
-	if ((u64)gd->ram_size > 0xfffff000)
-		bootpg = 0xfffff000;
-	else
-		bootpg = gd->ram_size - 4096;
+	u32 bootpg = determine_mp_bootpg();
 
 	lmb_reserve(lmb, bootpg, 4096);
 }
@@ -203,13 +207,7 @@ void setup_mp(void)
 {
 	extern ulong __secondary_start_page;
 	ulong fixup = (ulong)&__secondary_start_page;
-	u32 bootpg;
-
-	/* if we have 4G or more of memory, put the boot page at 4Gb-4k */
-	if ((u64)gd->ram_size > 0xfffff000)
-		bootpg = 0xfffff000;
-	else
-		bootpg = gd->ram_size - 4096;
+	u32 bootpg = determine_mp_bootpg();
 
 	memcpy((void *)bootpg, (void *)fixup, 4096);
 	flush_cache(bootpg, 4096);

cpu/mpc85xx/mp.h

@@ -1,10 +1,10 @@
 #ifndef __MPC85XX_MP_H_
 #define __MPC85XX_MP_H_
 
+#include <asm/mp.h>
+
 ulong get_spin_addr(void);
-void setup_mp(void);
 u32 get_my_id(void);
-void cpu_mp_lmb_reserve(struct lmb *lmb);
 
 #define BOOT_ENTRY_ADDR_UPPER	0
 #define BOOT_ENTRY_ADDR_LOWER	1