From: Aaron Sierra asierra@xes-inc.com
Some OSes require that secondary cores not be initialized when they are booted (eg VxWorks). By default when U-Boot is compiled with the CONFIG_MP option all secondary cores are brought out of reset and held in spinloops. Setting the "mp_holdoff" environment variable to 'yes' or '1' will cause U-Boot to leave secondary cores in their default state.
Signed-off-by: Aaron Sierra asierra@xes-inc.com Signed-off-by: Peter Tyser ptyser@xes-inc.com --- Changes since v1: - Update 'enable-method' in dtb appropriately - Don't set cpu-release-addr if spin-table isn't used - Add hold_cores_in_reset() function with more intelligent mp_holdoff environment variable checking
Changes since v2: - Fixed enable-method inconsistency pointed out by Scott
arch/powerpc/cpu/mpc85xx/fdt.c | 22 +++++++++++++++++++--- arch/powerpc/cpu/mpc85xx/mp.c | 31 +++++++++++++++++++++++++++++++ arch/powerpc/cpu/mpc85xx/mp.h | 1 + 3 files changed, 51 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/cpu/mpc85xx/fdt.c b/arch/powerpc/cpu/mpc85xx/fdt.c index 4540364..dee6e9b 100644 --- a/arch/powerpc/cpu/mpc85xx/fdt.c +++ b/arch/powerpc/cpu/mpc85xx/fdt.c @@ -48,6 +48,7 @@ void ft_fixup_cpu(void *blob, u64 memory_limit) ulong spin_tbl_addr = get_spin_phys_addr(); u32 bootpg = determine_mp_bootpg(); u32 id = get_my_id(); + const char *enable_method;
off = fdt_node_offset_by_prop_value(blob, -1, "device_type", "cpu", 4); while (off != -FDT_ERR_NOTFOUND) { @@ -63,10 +64,25 @@ void ft_fixup_cpu(void *blob, u64 memory_limit) fdt_setprop_string(blob, off, "status", "disabled"); } + + if (hold_cores_in_reset(0)) { +#ifdef CONFIG_FSL_CORENET + /* Cores held in reset, use BRR to release */ + enable_method = "fsl,brr-holdoff"; +#else + /* Cores held in reset, use EEBPCR to release */ + enable_method = "fsl,eebpcr-holdoff"; +#endif + } else { + /* Cores out of reset and in a spin-loop */ + enable_method = "spin-table"; + + fdt_setprop(blob, off, "cpu-release-addr", + &val, sizeof(val)); + } + fdt_setprop_string(blob, off, "enable-method", - "spin-table"); - fdt_setprop(blob, off, "cpu-release-addr", - &val, sizeof(val)); + enable_method); } else { printf ("cpu NULL\n"); } diff --git a/arch/powerpc/cpu/mpc85xx/mp.c b/arch/powerpc/cpu/mpc85xx/mp.c index 603baef..a019b1b 100644 --- a/arch/powerpc/cpu/mpc85xx/mp.c +++ b/arch/powerpc/cpu/mpc85xx/mp.c @@ -36,6 +36,27 @@ u32 get_my_id() return mfspr(SPRN_PIR); }
+/* + * Determine if U-Boot should keep secondary cores in reset, or let them out + * of reset and hold them in a spinloop + */ +int hold_cores_in_reset(int verbose) +{ + const char *s = getenv("mp_holdoff"); + + /* Default to no, overriden by 'y', 'yes', 'Y', 'Yes', or '1' */ + if (s && (*s == 'y' || *s == 'Y' || *s == '1')) { + if (verbose) { + puts("Secondary cores are being held in reset.\n"); + puts("See 'mp_holdoff' environment variable\n"); + } + + return 1; + } + + return 0; +} + int cpu_reset(int nr) { volatile ccsr_pic_t *pic = (void *)(CONFIG_SYS_MPC8xxx_PIC_ADDR); @@ -51,6 +72,9 @@ int cpu_status(int nr) { u32 *table, id = get_my_id();
+ if (hold_cores_in_reset(1)) + return 0; + if (nr == id) { table = (u32 *)get_spin_virt_addr(); printf("table base @ 0x%p\n", table); @@ -133,6 +157,9 @@ int cpu_release(int nr, int argc, char * const argv[]) u32 i, val, *table = (u32 *)get_spin_virt_addr() + nr * NUM_BOOT_ENTRY; u64 boot_addr;
+ if (hold_cores_in_reset(1)) + return 0; + if (nr == get_my_id()) { printf("Invalid to release the boot core.\n\n"); return 1; @@ -353,6 +380,10 @@ void setup_mp(void) ulong fixup = (ulong)&__secondary_start_page; u32 bootpg = determine_mp_bootpg();
+ /* Some OSes expect secondary cores to be held in reset */ + if (hold_cores_in_reset(0)) + return; + /* Store the bootpg's SDRAM address for use by secondary CPU cores */ __bootpg_addr = bootpg;
diff --git a/arch/powerpc/cpu/mpc85xx/mp.h b/arch/powerpc/cpu/mpc85xx/mp.h index 3422cc1..87bac37 100644 --- a/arch/powerpc/cpu/mpc85xx/mp.h +++ b/arch/powerpc/cpu/mpc85xx/mp.h @@ -6,6 +6,7 @@ ulong get_spin_phys_addr(void); ulong get_spin_virt_addr(void); u32 get_my_id(void); +int hold_cores_in_reset(int verbose);
#define BOOT_ENTRY_ADDR_UPPER 0 #define BOOT_ENTRY_ADDR_LOWER 1