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From 9398729313b826469fede3acda5fedd1eb21cb3e Mon Sep 17 00:00:00 2001
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Date: Wed, 5 Jun 2013 09:04:54 +0200
Subject: [PATCH 024/203] arm: mvebu: remove dependency of SMP init on static
I/O mapping
The ->smp_init_cpus() function is called very early during boot, at a
point where dynamic I/O mappings are not yet possible. However, in the
Armada 370/XP implementation of this function, we have to get the
number of CPUs. We used to do that by accessing a hardware register,
which requires relying on a static I/O mapping set up by
->map_io(). Not only this requires hardcoding a virtual address, but
it also prevents us from removing the static I/O mapping.
So this commit changes the way used to get the number of CPUs: we now
use the Device Tree, which is a representation of the hardware, and
provides us the number of available CPUs. This is also more accurate,
because it potentially allows to boot the Linux kernel on only a
number of CPUs given by the Device Tree, instead of unconditionally on
all CPUs.
As a consequence, the coherency_get_cpu_count() function becomes no
longer used, so we remove it.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
---
arch/arm/mach-mvebu/coherency.c | 12 ------------
arch/arm/mach-mvebu/coherency.h | 4 ----
arch/arm/mach-mvebu/common.h | 2 ++
arch/arm/mach-mvebu/platsmp.c | 10 +++++++++-
4 files changed, 11 insertions(+), 17 deletions(-)
--- a/arch/arm/mach-mvebu/coherency.c
+++ b/arch/arm/mach-mvebu/coherency.c
@@ -47,18 +47,6 @@ static struct of_device_id of_coherency_
{ /* end of list */ },
};
-#ifdef CONFIG_SMP
-int coherency_get_cpu_count(void)
-{
- int reg, cnt;
-
- reg = readl(coherency_base + COHERENCY_FABRIC_CFG_OFFSET);
- cnt = (reg & 0xF) + 1;
-
- return cnt;
-}
-#endif
-
/* Function defined in coherency_ll.S */
int ll_set_cpu_coherent(void __iomem *base_addr, unsigned int hw_cpu_id);
--- a/arch/arm/mach-mvebu/coherency.h
+++ b/arch/arm/mach-mvebu/coherency.h
@@ -14,10 +14,6 @@
#ifndef __MACH_370_XP_COHERENCY_H
#define __MACH_370_XP_COHERENCY_H
-#ifdef CONFIG_SMP
-int coherency_get_cpu_count(void);
-#endif
-
int set_cpu_coherent(int cpu_id, int smp_group_id);
int coherency_init(void);
--- a/arch/arm/mach-mvebu/common.h
+++ b/arch/arm/mach-mvebu/common.h
@@ -15,6 +15,8 @@
#ifndef __ARCH_MVEBU_COMMON_H
#define __ARCH_MVEBU_COMMON_H
+#define ARMADA_XP_MAX_CPUS 4
+
void mvebu_restart(char mode, const char *cmd);
void armada_370_xp_init_irq(void);
--- a/arch/arm/mach-mvebu/platsmp.c
+++ b/arch/arm/mach-mvebu/platsmp.c
@@ -88,8 +88,16 @@ static int __cpuinit armada_xp_boot_seco
static void __init armada_xp_smp_init_cpus(void)
{
+ struct device_node *np;
unsigned int i, ncores;
- ncores = coherency_get_cpu_count();
+
+ np = of_find_node_by_name(NULL, "cpus");
+ if (!np)
+ panic("No 'cpus' node found\n");
+
+ ncores = of_get_child_count(np);
+ if (ncores == 0 || ncores > ARMADA_XP_MAX_CPUS)
+ panic("Invalid number of CPUs in DT\n");
/* Limit possible CPUs to defconfig */
if (ncores > nr_cpu_ids) {
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