The method to detect the number of CPU cores on Cortex-A9 MPCore and
Cortex-A15 MPCore is different. On Cortex-A9 MPCore we can get this
information from the Snoop Control Unit(SCU). On Cortex-A15 MPCore we
have to read it from the system coprocessor(CP15), because the SCU on
Cortex-A15 MPCore does not have software readable registers. This
patch selects the correct method at runtime based on the CPU ID.
Signed-off-by: Hiroshi Doyu <hd...@nvidia.com>
---
arch/arm/mach-tegra/platsmp.c | 31 ++++++++++++++++++++++++++++---
1 file changed, 28 insertions(+), 3 deletions(-)
diff --git a/arch/arm/mach-tegra/platsmp.c b/arch/arm/mach-tegra/platsmp.c
index 1b926df..68e76ef 100644
--- a/arch/arm/mach-tegra/platsmp.c
+++ b/arch/arm/mach-tegra/platsmp.c
@@ -23,6 +23,7 @@
#include <asm/hardware/gic.h>
#include <asm/mach-types.h>
#include <asm/smp_scu.h>
+#include <asm/cputype.h>
#include <mach/powergate.h>
@@ -34,9 +35,13 @@
#include "common.h"
#include "iomap.h"
+#define CPU_MASK 0xff0ffff0
+#define CPU_CORTEX_A9 0x410fc090
+#define CPU_CORTEX_A15 0x410fc0f0
+
extern void tegra_secondary_startup(void);
-static void __iomem *scu_base = IO_ADDRESS(TEGRA_ARM_PERIF_BASE);
+static void __iomem *scu_base;
#define EVP_CPU_RESET_VECTOR \
(IO_ADDRESS(TEGRA_EXCEPTION_VECTORS_BASE) + 0x100)
@@ -149,7 +154,26 @@ done:
*/
static void __init tegra_smp_init_cpus(void)
{
- unsigned int i, ncores = scu_get_core_count(scu_base);
+ unsigned int i, cpu_id, ncores;
+ u32 l2ctlr;
+ phys_addr_t pa;
+
+ cpu_id = read_cpuid(CPUID_ID) & CPU_MASK;
+ switch (cpu_id) {
+ case CPU_CORTEX_A15:
+ asm("mrc p15, 1, %0, c9, c0, 2\n" : "=r" (l2ctlr));
+ ncores = ((l2ctlr >> 24) & 3) + 1;
+ break;
+ case CPU_CORTEX_A9:
+ /* Get SCU physical base */
+ asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (pa));
+ scu_base = IO_ADDRESS(pa);
+ ncores = scu_get_core_count(scu_base);
+ break;
+ default:
+ BUG();
+ break;
+ }
if (ncores > nr_cpu_ids) {
pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
@@ -166,7 +190,8 @@ static void __init tegra_smp_init_cpus(void)
static void __init tegra_smp_prepare_cpus(unsigned int max_cpus)
{
tegra_cpu_reset_handler_init();
- scu_enable(scu_base);
+ if (scu_base)
+ scu_enable(scu_base);
}
struct smp_operations tegra_smp_ops __initdata = {
--
1.7.9.5
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