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Subject[RESEND PATCH 1/4] ARM: msm: Remove pen_release usage
Date
pen_release is no longer required as the synchronization
is now managed by generic arm code.
This is done as suggested in https://lkml.org/lkml/2013/6/4/184

Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>
---
arch/arm/mach-msm/Makefile | 2 +-
arch/arm/mach-msm/headsmp.S | 39 ---------------------------------------
arch/arm/mach-msm/hotplug.c | 31 ++++---------------------------
arch/arm/mach-msm/platsmp.c | 35 +++--------------------------------
4 files changed, 8 insertions(+), 99 deletions(-)
delete mode 100644 arch/arm/mach-msm/headsmp.S

diff --git a/arch/arm/mach-msm/Makefile b/arch/arm/mach-msm/Makefile
index 80e3b15..14e22f9 100644
--- a/arch/arm/mach-msm/Makefile
+++ b/arch/arm/mach-msm/Makefile
@@ -20,7 +20,7 @@ obj-$(CONFIG_MSM_SCM) += scm.o scm-boot.o
CFLAGS_scm.o :=$(call as-instr,.arch_extension sec,-DREQUIRES_SEC=1)

obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o
-obj-$(CONFIG_SMP) += headsmp.o platsmp.o
+obj-$(CONFIG_SMP) += platsmp.o

obj-$(CONFIG_MACH_TROUT) += board-trout.o board-trout-gpio.o board-trout-mmc.o devices-msm7x00.o
obj-$(CONFIG_MACH_TROUT) += board-trout.o board-trout-gpio.o board-trout-mmc.o board-trout-panel.o devices-msm7x00.o
diff --git a/arch/arm/mach-msm/headsmp.S b/arch/arm/mach-msm/headsmp.S
deleted file mode 100644
index 6c62c3f..0000000
--- a/arch/arm/mach-msm/headsmp.S
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
- * linux/arch/arm/mach-realview/headsmp.S
- *
- * Copyright (c) 2003 ARM Limited
- * All Rights Reserved
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#include <linux/linkage.h>
-#include <linux/init.h>
-
-/*
- * MSM specific entry point for secondary CPUs. This provides
- * a "holding pen" into which all secondary cores are held until we're
- * ready for them to initialise.
- */
-ENTRY(msm_secondary_startup)
- mrc p15, 0, r0, c0, c0, 5
- and r0, r0, #15
- adr r4, 1f
- ldmia r4, {r5, r6}
- sub r4, r4, r5
- add r6, r6, r4
-pen: ldr r7, [r6]
- cmp r7, r0
- bne pen
-
- /*
- * we've been released from the holding pen: secondary_stack
- * should now contain the SVC stack for this core
- */
- b secondary_startup
-ENDPROC(msm_secondary_startup)
-
- .align
-1: .long .
- .long pen_release
diff --git a/arch/arm/mach-msm/hotplug.c b/arch/arm/mach-msm/hotplug.c
index 326a872..cea80fc 100644
--- a/arch/arm/mach-msm/hotplug.c
+++ b/arch/arm/mach-msm/hotplug.c
@@ -24,33 +24,10 @@ static inline void cpu_leave_lowpower(void)

static inline void platform_do_lowpower(unsigned int cpu)
{
- /* Just enter wfi for now. TODO: Properly shut off the cpu. */
- for (;;) {
- /*
- * here's the WFI
- */
- asm("wfi"
- :
- :
- : "memory", "cc");
-
- if (pen_release == cpu_logical_map(cpu)) {
- /*
- * OK, proper wakeup, we're done
- */
- break;
- }
-
- /*
- * getting here, means that we have come out of WFI without
- * having been woken up - this shouldn't happen
- *
- * The trouble is, letting people know about this is not really
- * possible, since we are currently running incoherently, and
- * therefore cannot safely call printk() or anything else
- */
- pr_debug("CPU%u: spurious wakeup call\n", cpu);
- }
+ asm("wfi"
+ :
+ :
+ : "memory", "cc");
}

/*
diff --git a/arch/arm/mach-msm/platsmp.c b/arch/arm/mach-msm/platsmp.c
index 3f06edc..5b481db 100644
--- a/arch/arm/mach-msm/platsmp.c
+++ b/arch/arm/mach-msm/platsmp.c
@@ -28,7 +28,7 @@
#define SCSS_CPU1CORE_RESET 0xD80
#define SCSS_DBG_STATUS_CORE_PWRDUP 0xE64

-extern void msm_secondary_startup(void);
+extern void secondary_startup(void);

static DEFINE_SPINLOCK(boot_lock);

@@ -41,13 +41,6 @@ static inline int get_core_count(void)
static void msm_secondary_init(unsigned int cpu)
{
/*
- * let the primary processor know we're out of the
- * pen, then head off into the C entry point
- */
- pen_release = -1;
- smp_wmb();
-
- /*
* Synchronise with the boot thread.
*/
spin_lock(&boot_lock);
@@ -57,7 +50,7 @@ static void msm_secondary_init(unsigned int cpu)
static void prepare_cold_cpu(unsigned int cpu)
{
int ret;
- ret = scm_set_boot_addr(virt_to_phys(msm_secondary_startup),
+ ret = scm_set_boot_addr(virt_to_phys(secondary_startup),
SCM_FLAG_COLDBOOT_CPU1);
if (ret == 0) {
void __iomem *sc1_base_ptr;
@@ -75,7 +68,6 @@ static void prepare_cold_cpu(unsigned int cpu)

static int msm_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
- unsigned long timeout;
static int cold_boot_done;

/* Only need to bring cpu out of reset this way once */
@@ -91,40 +83,19 @@ static int msm_boot_secondary(unsigned int cpu, struct task_struct *idle)
spin_lock(&boot_lock);

/*
- * The secondary processor is waiting to be released from
- * the holding pen - release it, then wait for it to flag
- * that it has been released by resetting pen_release.
- *
- * Note that "pen_release" is the hardware CPU ID, whereas
- * "cpu" is Linux's internal ID.
- */
- pen_release = cpu_logical_map(cpu);
- __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
- outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
-
- /*
* Send the secondary CPU a soft interrupt, thereby causing
* the boot monitor to read the system wide flags register,
* and branch to the address found there.
*/
arch_send_wakeup_ipi_mask(cpumask_of(cpu));

- timeout = jiffies + (1 * HZ);
- while (time_before(jiffies, timeout)) {
- smp_rmb();
- if (pen_release == -1)
- break;
-
- udelay(10);
- }
-
/*
* now the secondary core is starting up let it run its
* calibrations, then wait for it to finish
*/
spin_unlock(&boot_lock);

- return pen_release != -1 ? -ENOSYS : 0;
+ return 0;
}

/*
--
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