linux/arch/mips/loongson/loongson-3/smp.h
Huacai Chen 300459d558 MIPS: Loongson 3: Add Loongson-3 SMP support
IPI registers of Loongson-3 include IPI_SET, IPI_CLEAR, IPI_STATUS,
IPI_EN and IPI_MAILBOX_BUF. Each bit of IPI_STATUS indicate a type of
IPI and IPI_EN indicate whether the IPI is enabled. The sender write 1
to IPI_SET bits generate IPIs in IPI_STATUS, and receiver write 1 to
bits of IPI_CLEAR to clear IPIs. IPI_MAILBOX_BUF are used to deliver
more information about IPIs.

Why we change code in arch/mips/loongson/common/setup.c?

If without this change, when SMP configured, system cannot boot since
it hang at printk() in cgroup_init_early(). The root cause is:

console_trylock()
  \-->down_trylock(&console_sem)
    \-->raw_spin_unlock_irqrestore(&sem->lock, flags)
      \-->_raw_spin_unlock_irqrestore()(SMP/UP have different versions)
        \-->__raw_spin_unlock_irqrestore()  (following is the SMP case)
          \-->do_raw_spin_unlock()
            \-->arch_spin_unlock()
              \-->nudge_writes()
                \-->mb()
                  \-->wbflush()
                    \-->__wbflush()

In previous code __wbflush() is initialized in plat_mem_setup(), but
cgroup_init_early() is called before plat_mem_setup(). Therefore, In
this patch we make changes to avoid boot failure.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Hongliang Tao <taohl@lemote.com>
Signed-off-by: Hua Yan <yanh@lemote.com>
Tested-by: Alex Smith <alex.smith@imgtec.com>
Reviewed-by: Alex Smith <alex.smith@imgtec.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/6638
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-03-31 18:17:12 +02:00

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C

#ifndef __LOONGSON_SMP_H_
#define __LOONGSON_SMP_H_
/* for Loongson-3A smp support */
/* 4 groups(nodes) in maximum in numa case */
#define SMP_CORE_GROUP0_BASE 0x900000003ff01000
#define SMP_CORE_GROUP1_BASE 0x900010003ff01000
#define SMP_CORE_GROUP2_BASE 0x900020003ff01000
#define SMP_CORE_GROUP3_BASE 0x900030003ff01000
/* 4 cores in each group(node) */
#define SMP_CORE0_OFFSET 0x000
#define SMP_CORE1_OFFSET 0x100
#define SMP_CORE2_OFFSET 0x200
#define SMP_CORE3_OFFSET 0x300
/* ipi registers offsets */
#define STATUS0 0x00
#define EN0 0x04
#define SET0 0x08
#define CLEAR0 0x0c
#define STATUS1 0x10
#define MASK1 0x14
#define SET1 0x18
#define CLEAR1 0x1c
#define BUF 0x20
#endif