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