MIPS: smp-cps: rework core/VPE initialisation

When hotplug and/or a powered down idle state are supported cases will
arise where a non-zero VPE must be brought online without VPE 0, and it
where multiple VPEs must be onlined simultaneously. This patch prepares
for that by:

  - Splitting struct boot_config into core & VPE boot config structures,
    allocated one per core or VPE respectively. This allows for multiple
    VPEs to be onlined simultaneously without clobbering each others
    configuration.

  - Indicating which VPEs should be online within a core at any given
    time using a bitmap. This allows multiple VPEs to be brought online
    simultaneously and also indicates to VPE 0 whether it should halt
    after starting any non-zero VPEs that should be online within the
    core. For example if all VPEs within a core are offlined via hotplug
    and the user onlines the second VPE within that core:

      1) The core will be powered up.

      2) VPE 0 will run from the BEV (ie. mips_cps_core_entry) to
         initialise the core.

      3) VPE 0 will start VPE 1 because its bit is set in the cores
         bitmap.

      4) VPE 0 will halt itself because its bit is clear in the cores
         bitmap.

  - Moving the core & VPE initialisation to assembly code which does not
    make any use of the stack. This is because if a non-zero VPE is to
    be brought online in a powered down core then when VPE 0 of that
    core runs it may not have a valid stack, and even if it did then
    it's messy to run through parts of generic kernel code on VPE 0
    before starting the correct VPE.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/arch/mips/include/asm/smp-cps.h b/arch/mips/include/asm/smp-cps.h
index d60d1a2180d1..d49279e92eb5 100644
--- a/arch/mips/include/asm/smp-cps.h
+++ b/arch/mips/include/asm/smp-cps.h
@@ -13,17 +13,23 @@
 
 #ifndef __ASSEMBLY__
 
-struct boot_config {
-	unsigned int core;
-	unsigned int vpe;
+struct vpe_boot_config {
 	unsigned long pc;
 	unsigned long sp;
 	unsigned long gp;
 };
 
-extern struct boot_config mips_cps_bootcfg;
+struct core_boot_config {
+	atomic_t vpe_mask;
+	struct vpe_boot_config *vpe_config;
+};
+
+extern struct core_boot_config *mips_cps_core_bootcfg;
 
 extern void mips_cps_core_entry(void);
+extern void mips_cps_core_init(void);
+
+extern struct vpe_boot_config *mips_cps_boot_vpes(void);
 
 #else /* __ASSEMBLY__ */