With SBI v0.2 HSM extension, only a single hart need to boot and
enter operating system. The booting hart can bring up secondary
harts one by one afterwards.

For U-Boot running in SPL, SMP can be turned on, while in U-Boot
proper, SMP can be optionally turned off if using SBI v0.2 HSM.

Introduce a new SPL_SMP Kconfig option to support this.

Signed-off-by: Bin Meng <bmeng...@gmail.com>
Reviewed-by: Atish Patra <atish.pa...@wdc.com>
---

Changes in v2: None

 arch/riscv/Kconfig                   | 13 ++++++++++++-
 arch/riscv/cpu/start.S               | 14 +++++++-------
 arch/riscv/include/asm/global_data.h |  2 +-
 arch/riscv/lib/Makefile              |  2 +-
 arch/riscv/lib/spl.c                 |  2 +-
 common/spl/spl_opensbi.c             |  2 +-
 6 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 3061bf8..5ef6849 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -200,10 +200,21 @@ config SMP
          machine. If you say Y here, U-Boot will run on many, but not
          all, single processor machines.
 
+config SPL_SMP
+       bool "Symmetric Multi-Processing in SPL"
+       depends on SPL && SPL_RISCV_MMODE
+       default y
+       help
+         This enables support for systems with more than one CPU in SPL.
+         If you say N here, U-Boot SPL will run on single and multiprocessor
+         machines, but will use only one CPU of a multiprocessor
+         machine. If you say Y here, U-Boot SPL will run on many, but not
+         all, single processor machines.
+
 config NR_CPUS
        int "Maximum number of CPUs (2-32)"
        range 2 32
-       depends on SMP
+       depends on SMP || SPL_SMP
        default 8
        help
          On multiprocessor machines, U-Boot sets up a stack for each CPU.
diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S
index ecf0482..fce0982 100644
--- a/arch/riscv/cpu/start.S
+++ b/arch/riscv/cpu/start.S
@@ -53,7 +53,7 @@ _start:
        /* mask all interrupts */
        csrw    MODE_PREFIX(ie), zero
 
-#ifdef CONFIG_SMP
+#if CONFIG_IS_ENABLED(SMP)
        /* check if hart is within range */
        /* tp: hart id */
        li      t0, CONFIG_NR_CPUS
@@ -91,7 +91,7 @@ call_board_init_f_0:
        mv      gp, a0
 
        /* setup stack */
-#ifdef CONFIG_SMP
+#if CONFIG_IS_ENABLED(SMP)
        /* tp: hart id */
        slli    t0, tp, CONFIG_STACK_SIZE_SHIFT
        sub     sp, a0, t0
@@ -182,7 +182,7 @@ spl_stack_gd_setup:
        mv      s0, a0
 
        /* setup stack on main hart */
-#ifdef CONFIG_SMP
+#if CONFIG_IS_ENABLED(SMP)
        /* tp: hart id */
        slli    t0, tp, CONFIG_STACK_SIZE_SHIFT
        sub     sp, s0, t0
@@ -231,7 +231,7 @@ relocate_code:
  *Set up the stack
  */
 stack_setup:
-#ifdef CONFIG_SMP
+#if CONFIG_IS_ENABLED(SMP)
        /* tp: hart id */
        slli    t0, tp, CONFIG_STACK_SIZE_SHIFT
        sub     sp, s2, t0
@@ -326,7 +326,7 @@ clbss_l:
        blt     t0, t1, clbss_l
 
 relocate_secondary_harts:
-#ifdef CONFIG_SMP
+#if CONFIG_IS_ENABLED(SMP)
        /* send relocation IPI */
        la      t0, secondary_hart_relocate
        add     a0, t0, t6
@@ -370,7 +370,7 @@ call_board_init_r:
  */
        jr      t4                      /* jump to board_init_r() */
 
-#ifdef CONFIG_SMP
+#if CONFIG_IS_ENABLED(SMP)
 hart_out_of_bounds_loop:
        /* Harts in this loop are out of bounds, increase CONFIG_NR_CPUS. */
        wfi
@@ -393,7 +393,7 @@ secondary_hart_relocate:
 secondary_hart_loop:
        wfi
 
-#ifdef CONFIG_SMP
+#if CONFIG_IS_ENABLED(SMP)
        csrr    t0, MODE_PREFIX(ip)
 #if CONFIG_IS_ENABLED(RISCV_MMODE)
        andi    t0, t0, MIE_MSIE
diff --git a/arch/riscv/include/asm/global_data.h 
b/arch/riscv/include/asm/global_data.h
index b74bd7e..72fb4b4 100644
--- a/arch/riscv/include/asm/global_data.h
+++ b/arch/riscv/include/asm/global_data.h
@@ -24,7 +24,7 @@ struct arch_global_data {
 #ifdef CONFIG_ANDES_PLMT
        void __iomem *plmt;     /* plmt base address */
 #endif
-#ifdef CONFIG_SMP
+#if CONFIG_IS_ENABLED(SMP)
        struct ipi_data ipi[CONFIG_NR_CPUS];
 #endif
 #ifndef CONFIG_XIP
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index adadbf4..bd7b2c4 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -22,7 +22,7 @@ endif
 obj-y  += interrupts.o
 obj-y  += reset.o
 obj-y   += setjmp.o
-obj-$(CONFIG_SMP) += smp.o
+obj-$(CONFIG_$(SPL_)SMP) += smp.o
 obj-$(CONFIG_SPL_BUILD)        += spl.o
 
 # For building EFI apps
diff --git a/arch/riscv/lib/spl.c b/arch/riscv/lib/spl.c
index ae07bbe..4ca038b 100644
--- a/arch/riscv/lib/spl.c
+++ b/arch/riscv/lib/spl.c
@@ -41,7 +41,7 @@ void __noreturn jump_to_image_no_args(struct spl_image_info 
*spl_image)
        invalidate_icache_all();
 
        debug("image entry point: 0x%lX\n", spl_image->entry_point);
-#ifdef CONFIG_SMP
+#ifdef CONFIG_SPL_SMP
        ret = smp_call_function(spl_image->entry_point, (ulong)fdt_blob, 0, 0);
        if (ret)
                hang();
diff --git a/common/spl/spl_opensbi.c b/common/spl/spl_opensbi.c
index a136073..3519c34 100644
--- a/common/spl/spl_opensbi.c
+++ b/common/spl/spl_opensbi.c
@@ -76,7 +76,7 @@ void spl_invoke_opensbi(struct spl_image_info *spl_image)
        opensbi_entry = (void (*)(ulong, ulong, ulong))spl_image->entry_point;
        invalidate_icache_all();
 
-#ifdef CONFIG_SMP
+#ifdef CONFIG_SPL_SMP
        /*
         * Start OpenSBI on all secondary harts and wait for acknowledgment.
         *
-- 
2.7.4

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