[PATCH 1/2] ARM: SH-Mobile: sh73a0: Secondary CPUs handle own SCU flags
Bastian Hecht
hechtb at gmail.com
Thu Dec 6 07:08:38 EST 2012
From: Bastian Hecht <hechtb at gmail.com>
When booting secondary CPUs we have used the main CPU to set up the
Snoop Control Unit flags of these CPUs. It is a cleaner approach
if every CPU takes care of its own flags. We avoid the need for
locking and the program logic is more concise. With this patch the file
headsmp-sh73a0.S is added that contains a startup vector for secondary CPUs
that sets up its own SCU flags.
Further in sh73a0_smp_prepare_cpus() we can rely on the generic ARM helper
scu_power_mode(). This is possible as we don't cross borders anymore (every
CPU handles its own flags) and need no locking. So we can throw out the
needless function modify_scu_cpu_psr().
Signed-off-by: Bastian Hecht <hechtb+renesas at gmail.com>
---
arch/arm/mach-shmobile/Makefile | 2 +-
arch/arm/mach-shmobile/headsmp-sh73a0.S | 50 ++++++++++++++++++++++++++
arch/arm/mach-shmobile/include/mach/common.h | 1 +
arch/arm/mach-shmobile/smp-sh73a0.c | 30 +++-------------
4 files changed, 56 insertions(+), 27 deletions(-)
create mode 100644 arch/arm/mach-shmobile/headsmp-sh73a0.S
diff --git a/arch/arm/mach-shmobile/Makefile b/arch/arm/mach-shmobile/Makefile
index fe2c97c..a7beb61 100644
--- a/arch/arm/mach-shmobile/Makefile
+++ b/arch/arm/mach-shmobile/Makefile
@@ -17,7 +17,7 @@ obj-$(CONFIG_ARCH_EMEV2) += setup-emev2.o clock-emev2.o
# SMP objects
smp-y := platsmp.o headsmp.o
smp-$(CONFIG_HOTPLUG_CPU) += hotplug.o
-smp-$(CONFIG_ARCH_SH73A0) += smp-sh73a0.o
+smp-$(CONFIG_ARCH_SH73A0) += smp-sh73a0.o headsmp-sh73a0.o
smp-$(CONFIG_ARCH_R8A7779) += smp-r8a7779.o
smp-$(CONFIG_ARCH_EMEV2) += smp-emev2.o
diff --git a/arch/arm/mach-shmobile/headsmp-sh73a0.S b/arch/arm/mach-shmobile/headsmp-sh73a0.S
new file mode 100644
index 0000000..bec4c0d
--- /dev/null
+++ b/arch/arm/mach-shmobile/headsmp-sh73a0.S
@@ -0,0 +1,50 @@
+/*
+ * SMP support for SoC sh73a0
+ *
+ * Copyright (C) 2012 Bastian Hecht
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR /PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/memory.h>
+
+ __CPUINIT
+/*
+ * Reset vector for secondary CPUs.
+ *
+ * First we turn on L1 cache coherency for our CPU. Then we jump to
+ * shmobile_invalidate_start that invalidates the cache and hands over control
+ * to the common ARM startup code.
+ * This function will be mapped to address 0 by the SBAR register.
+ * A normal branch is out of range here so we need a long jump. We jump to
+ * the physical address as the MMU is still turned off.
+ */
+ .align 12
+ENTRY(sh73a0_secondary_vector)
+ mrc p15, 0, r0, c0, c0, 5 @ read MIPDR
+ and r0, r0, #3 @ mask out cpu ID
+ lsl r0, r0, #3 @ we will shift by cpu_id * 8 bits
+ mov r1, #0xf0000000 @ SCU base address
+ ldr r2, [r1, #8] @ SCU Power Status Register
+ mov r3, #3
+ bic r2, r2, r3, lsl r0 @ Clear bits of our CPU (Run Mode)
+ str r2, [r1, #8] @ write back
+
+ ldr pc, 1f
+1: .long shmobile_invalidate_start - PAGE_OFFSET + PLAT_PHYS_OFFSET
+ENDPROC(sh73a0_secondary_vector)
diff --git a/arch/arm/mach-shmobile/include/mach/common.h b/arch/arm/mach-shmobile/include/mach/common.h
index d47e215..f2e2c29 100644
--- a/arch/arm/mach-shmobile/include/mach/common.h
+++ b/arch/arm/mach-shmobile/include/mach/common.h
@@ -54,6 +54,7 @@ extern void sh73a0_add_early_devices(void);
extern void sh73a0_add_standard_devices(void);
extern void sh73a0_clock_init(void);
extern void sh73a0_pinmux_init(void);
+extern void sh73a0_secondary_vector(void);
extern struct clk sh73a0_extal1_clk;
extern struct clk sh73a0_extal2_clk;
extern struct clk sh73a0_extcki_clk;
diff --git a/arch/arm/mach-shmobile/smp-sh73a0.c b/arch/arm/mach-shmobile/smp-sh73a0.c
index 624f00f..5e36f5d 100644
--- a/arch/arm/mach-shmobile/smp-sh73a0.c
+++ b/arch/arm/mach-shmobile/smp-sh73a0.c
@@ -41,9 +41,6 @@ static void __iomem *scu_base_addr(void)
return (void __iomem *)0xf0000000;
}
-static DEFINE_SPINLOCK(scu_lock);
-static unsigned long tmp;
-
#ifdef CONFIG_HAVE_ARM_TWD
static DEFINE_TWD_LOCAL_TIMER(twd_local_timer, 0xf0000600, 29);
void __init sh73a0_register_twd(void)
@@ -52,20 +49,6 @@ void __init sh73a0_register_twd(void)
}
#endif
-static void modify_scu_cpu_psr(unsigned long set, unsigned long clr)
-{
- void __iomem *scu_base = scu_base_addr();
-
- spin_lock(&scu_lock);
- tmp = __raw_readl(scu_base + 8);
- tmp &= ~clr;
- tmp |= set;
- spin_unlock(&scu_lock);
-
- /* disable cache coherency after releasing the lock */
- __raw_writel(tmp, scu_base + 8);
-}
-
static unsigned int __init sh73a0_get_core_count(void)
{
void __iomem *scu_base = scu_base_addr();
@@ -82,9 +65,6 @@ static int __cpuinit sh73a0_boot_secondary(unsigned int cpu, struct task_struct
{
cpu = cpu_logical_map(cpu);
- /* enable cache coherency */
- modify_scu_cpu_psr(0, 3 << (cpu * 8));
-
if (((__raw_readl(PSTR) >> (4 * cpu)) & 3) == 3)
__raw_writel(1 << cpu, WUPCR); /* wake up */
else
@@ -95,16 +75,14 @@ static int __cpuinit sh73a0_boot_secondary(unsigned int cpu, struct task_struct
static void __init sh73a0_smp_prepare_cpus(unsigned int max_cpus)
{
- int cpu = cpu_logical_map(0);
-
scu_enable(scu_base_addr());
- /* Map the reset vector (in headsmp.S) */
+ /* Map the reset vector (in headsmp-sh73a0.S) */
__raw_writel(0, APARMBAREA); /* 4k */
- __raw_writel(__pa(shmobile_secondary_vector), SBAR);
+ __raw_writel(__pa(sh73a0_secondary_vector), SBAR);
- /* enable cache coherency on CPU0 */
- modify_scu_cpu_psr(0, 3 << (cpu * 8));
+ /* enable cache coherency on booting CPU */
+ scu_power_mode(scu_base_addr(), SCU_PM_NORMAL);
}
static void __init sh73a0_smp_init_cpus(void)
--
1.7.9.5
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