From 9398729313b826469fede3acda5fedd1eb21cb3e Mon Sep 17 00:00:00 2001 From: Thomas Petazzoni 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 Acked-by: Arnd Bergmann Signed-off-by: Jason Cooper --- 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) {