| Message ID | 20200407072517.671521-1-joel@jms.id.au (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | aspeed: Add boot stub for smp booting | expand |
On Tue, 7 Apr 2020 at 07:25, Joel Stanley <joel@jms.id.au> wrote: > > This is a boot stub that is similar to the code u-boot runs, allowing > the kernel to boot the secondary CPU. > > u-boot works as follows: > > 1. Initialises the SMP mailbox area in the SCU at 0x1e6e2180 with default values > > 2. Copies a stub named 'mailbox_insn' from flash to the SCU, just above the > mailbox area > > 3. Sets AST_SMP_MBOX_FIELD_READY to a magic value to indicate the > secondary can begin execution from the stub > > 4. The stub waits until the AST_SMP_MBOX_FIELD_GOSIGN register is set to > a magic value > > 5. Jumps to the address in AST_SMP_MBOX_FIELD_ENTRY, starting Linux > > Linux indicates it is ready by writing the address of its entrypoint > function to AST_SMP_MBOX_FIELD_ENTRY and the 'go' magic number to > AST_SMP_MBOX_FIELD_GOSIGN. The secondary CPU sees this at step 4 and > breaks out of it's loop. > > To be compatible, a fixed qemu stub is loaded into the mailbox area. As > qemu can ensure the stub is loaded before execution starts, we do not > need to emulate the AST_SMP_MBOX_FIELD_READY behaviour of u-boot. The > secondary CPU's program counter points to the beginning of the stub, > allowing qemu to start secondaries at step four. > > Reboot behaviour is preserved by resetting AST_SMP_MBOX_FIELD_GOSIGN > when the secondaries are reset. > > This is only configured when the system is booted with -kernel and qemu > does not execute u-boot first. > > Signed-off-by: Joel Stanley <joel@jms.id.au> > --- > hw/arm/aspeed.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 65 insertions(+) > > diff --git a/hw/arm/aspeed.c b/hw/arm/aspeed.c > index a6a2102a93cb..bc4386cc6174 100644 > --- a/hw/arm/aspeed.c > +++ b/hw/arm/aspeed.c > @@ -116,6 +116,58 @@ static const MemoryRegionOps max_ram_ops = { > .endianness = DEVICE_NATIVE_ENDIAN, > }; > > +#define AST_SMP_MAILBOX_BASE 0x1e6e2180 > +#define AST_SMP_MBOX_FIELD_ENTRY (AST_SMP_MAILBOX_BASE + 0x0) > +#define AST_SMP_MBOX_FIELD_GOSIGN (AST_SMP_MAILBOX_BASE + 0x4) > +#define AST_SMP_MBOX_FIELD_READY (AST_SMP_MAILBOX_BASE + 0x8) > +#define AST_SMP_MBOX_FIELD_POLLINSN (AST_SMP_MAILBOX_BASE + 0xc) > +#define AST_SMP_MBOX_CODE (AST_SMP_MAILBOX_BASE + 0x10) > +#define AST_SMP_MBOX_GOSIGN 0xabbaab00 > + > +static void aspeed_write_smpboot(ARMCPU *cpu, > + const struct arm_boot_info *info) > +{ > + static const uint32_t poll_mailbox_ready[] = { > + /* > + * r2 = per-cpu go sign value > + * r1 = AST_SMP_MBOX_FIELD_ENTRY > + * r0 = AST_SMP_MBOX_FIELD_GOSIGN > + */ > + 0xee100fb0, /* mrc p15, 0, r0, c0, c0, 5 */ > + 0xe21000ff, /* ands r0, r0, #255 */ > + 0xe59f201c, /* ldr r2, [pc, #28] */ > + 0xe1822000, /* orr r2, r2, r0 */ > + > + 0xe59f1018, /* ldr r1, [pc, #24] */ > + 0xe59f0018, /* ldr r0, [pc, #24] */ > + > + 0xe320f002, /* wfe */ > + 0xe5904000, /* ldr r4, [r0] */ > + 0xe1520004, /* cmp r2, r4 */ > + 0x1afffffb, /* bne <wfe> */ > + 0xe591f000, /* ldr pc, [r1] */ > + AST_SMP_MBOX_GOSIGN, > + AST_SMP_MBOX_FIELD_ENTRY, > + AST_SMP_MBOX_FIELD_GOSIGN, > + }; > + > + rom_add_blob_fixed("aspeed.smpboot", poll_mailbox_ready, > + sizeof(poll_mailbox_ready), > + info->smp_loader_start); > +} > + > +static void aspeed_reset_secondary(ARMCPU *cpu, > + const struct arm_boot_info *info) > +{ > + AddressSpace *as = arm_boot_address_space(cpu, info); > + CPUState *cs = CPU(cpu); > + > + /* info->smp_bootreg_addr */ > + address_space_stl_notdirty(as, AST_SMP_MBOX_FIELD_GOSIGN, 0, > + MEMTXATTRS_UNSPECIFIED, NULL); > + cpu_set_pc(cs, info->smp_loader_start); > +} > + > #define FIRMWARE_ADDR 0x0 > > static void write_boot_rom(DriveInfo *dinfo, hwaddr addr, size_t rom_size, > @@ -270,6 +322,19 @@ static void aspeed_machine_init(MachineState *machine) > } > } > > + if (machine->kernel_filename) { I just realised this shouldn't be executed on non-ast2600 platforms. We could test for the number of CPUs like this: if (machine->kernel_filename && aspeed_board_binfo.nb_cpus > 1) { > + /* With no u-boot we must set up a boot stub for the secondary CPU */ > + MemoryRegion *smpboot = g_new(MemoryRegion, 1); > + memory_region_init_ram(smpboot, OBJECT(bmc), "aspeed.smpboot", > + 0x80, &error_abort); > + memory_region_add_subregion(get_system_memory(), > + AST_SMP_MAILBOX_BASE, smpboot); > + > + aspeed_board_binfo.write_secondary_boot = aspeed_write_smpboot; > + aspeed_board_binfo.secondary_cpu_reset_hook = aspeed_reset_secondary; > + aspeed_board_binfo.smp_loader_start = AST_SMP_MBOX_CODE; > + } > + > aspeed_board_binfo.ram_size = ram_size; > aspeed_board_binfo.loader_start = sc->memmap[ASPEED_SDRAM]; > aspeed_board_binfo.nb_cpus = bmc->soc.num_cpus; > -- > 2.25.1 >
On 4/7/20 9:38 AM, Joel Stanley wrote: > On Tue, 7 Apr 2020 at 07:25, Joel Stanley <joel@jms.id.au> wrote: >> >> This is a boot stub that is similar to the code u-boot runs, allowing >> the kernel to boot the secondary CPU. >> >> u-boot works as follows: >> >> 1. Initialises the SMP mailbox area in the SCU at 0x1e6e2180 with default values >> >> 2. Copies a stub named 'mailbox_insn' from flash to the SCU, just above the >> mailbox area >> >> 3. Sets AST_SMP_MBOX_FIELD_READY to a magic value to indicate the >> secondary can begin execution from the stub >> >> 4. The stub waits until the AST_SMP_MBOX_FIELD_GOSIGN register is set to >> a magic value >> >> 5. Jumps to the address in AST_SMP_MBOX_FIELD_ENTRY, starting Linux >> >> Linux indicates it is ready by writing the address of its entrypoint >> function to AST_SMP_MBOX_FIELD_ENTRY and the 'go' magic number to >> AST_SMP_MBOX_FIELD_GOSIGN. The secondary CPU sees this at step 4 and >> breaks out of it's loop. >> >> To be compatible, a fixed qemu stub is loaded into the mailbox area. As >> qemu can ensure the stub is loaded before execution starts, we do not >> need to emulate the AST_SMP_MBOX_FIELD_READY behaviour of u-boot. The >> secondary CPU's program counter points to the beginning of the stub, >> allowing qemu to start secondaries at step four. >> >> Reboot behaviour is preserved by resetting AST_SMP_MBOX_FIELD_GOSIGN >> when the secondaries are reset. >> >> This is only configured when the system is booted with -kernel and qemu >> does not execute u-boot first. >> >> Signed-off-by: Joel Stanley <joel@jms.id.au> >> --- >> hw/arm/aspeed.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 65 insertions(+) >> >> diff --git a/hw/arm/aspeed.c b/hw/arm/aspeed.c >> index a6a2102a93cb..bc4386cc6174 100644 >> --- a/hw/arm/aspeed.c >> +++ b/hw/arm/aspeed.c >> @@ -116,6 +116,58 @@ static const MemoryRegionOps max_ram_ops = { >> .endianness = DEVICE_NATIVE_ENDIAN, >> }; >> >> +#define AST_SMP_MAILBOX_BASE 0x1e6e2180 >> +#define AST_SMP_MBOX_FIELD_ENTRY (AST_SMP_MAILBOX_BASE + 0x0) >> +#define AST_SMP_MBOX_FIELD_GOSIGN (AST_SMP_MAILBOX_BASE + 0x4) >> +#define AST_SMP_MBOX_FIELD_READY (AST_SMP_MAILBOX_BASE + 0x8) >> +#define AST_SMP_MBOX_FIELD_POLLINSN (AST_SMP_MAILBOX_BASE + 0xc) >> +#define AST_SMP_MBOX_CODE (AST_SMP_MAILBOX_BASE + 0x10) >> +#define AST_SMP_MBOX_GOSIGN 0xabbaab00 >> + >> +static void aspeed_write_smpboot(ARMCPU *cpu, >> + const struct arm_boot_info *info) >> +{ >> + static const uint32_t poll_mailbox_ready[] = { >> + /* >> + * r2 = per-cpu go sign value >> + * r1 = AST_SMP_MBOX_FIELD_ENTRY >> + * r0 = AST_SMP_MBOX_FIELD_GOSIGN >> + */ >> + 0xee100fb0, /* mrc p15, 0, r0, c0, c0, 5 */ >> + 0xe21000ff, /* ands r0, r0, #255 */ >> + 0xe59f201c, /* ldr r2, [pc, #28] */ >> + 0xe1822000, /* orr r2, r2, r0 */ >> + >> + 0xe59f1018, /* ldr r1, [pc, #24] */ >> + 0xe59f0018, /* ldr r0, [pc, #24] */ >> + >> + 0xe320f002, /* wfe */ >> + 0xe5904000, /* ldr r4, [r0] */ >> + 0xe1520004, /* cmp r2, r4 */ >> + 0x1afffffb, /* bne <wfe> */ >> + 0xe591f000, /* ldr pc, [r1] */ >> + AST_SMP_MBOX_GOSIGN, >> + AST_SMP_MBOX_FIELD_ENTRY, >> + AST_SMP_MBOX_FIELD_GOSIGN, >> + }; >> + >> + rom_add_blob_fixed("aspeed.smpboot", poll_mailbox_ready, >> + sizeof(poll_mailbox_ready), >> + info->smp_loader_start); >> +} >> + >> +static void aspeed_reset_secondary(ARMCPU *cpu, >> + const struct arm_boot_info *info) >> +{ >> + AddressSpace *as = arm_boot_address_space(cpu, info); >> + CPUState *cs = CPU(cpu); >> + >> + /* info->smp_bootreg_addr */ >> + address_space_stl_notdirty(as, AST_SMP_MBOX_FIELD_GOSIGN, 0, >> + MEMTXATTRS_UNSPECIFIED, NULL); >> + cpu_set_pc(cs, info->smp_loader_start); >> +} >> + >> #define FIRMWARE_ADDR 0x0 >> >> static void write_boot_rom(DriveInfo *dinfo, hwaddr addr, size_t rom_size, >> @@ -270,6 +322,19 @@ static void aspeed_machine_init(MachineState *machine) >> } >> } >> >> + if (machine->kernel_filename) { > > I just realised this shouldn't be executed on non-ast2600 platforms. > We could test for the number of CPUs like this: > > if (machine->kernel_filename && aspeed_board_binfo.nb_cpus > 1) { if (!strcmp(amc->soc_name, "ast2600")) { ? > >> + /* With no u-boot we must set up a boot stub for the secondary CPU */ >> + MemoryRegion *smpboot = g_new(MemoryRegion, 1); >> + memory_region_init_ram(smpboot, OBJECT(bmc), "aspeed.smpboot", >> + 0x80, &error_abort); >> + memory_region_add_subregion(get_system_memory(), >> + AST_SMP_MAILBOX_BASE, smpboot); >> + >> + aspeed_board_binfo.write_secondary_boot = aspeed_write_smpboot; >> + aspeed_board_binfo.secondary_cpu_reset_hook = aspeed_reset_secondary; >> + aspeed_board_binfo.smp_loader_start = AST_SMP_MBOX_CODE; >> + } >> + >> aspeed_board_binfo.ram_size = ram_size; >> aspeed_board_binfo.loader_start = sc->memmap[ASPEED_SDRAM]; >> aspeed_board_binfo.nb_cpus = bmc->soc.num_cpus; >> -- >> 2.25.1 >> >
On 4/7/20 10:19 AM, Philippe Mathieu-Daudé wrote: > > > On 4/7/20 9:38 AM, Joel Stanley wrote: >> On Tue, 7 Apr 2020 at 07:25, Joel Stanley <joel@jms.id.au> wrote: >>> >>> This is a boot stub that is similar to the code u-boot runs, allowing >>> the kernel to boot the secondary CPU. >>> >>> u-boot works as follows: >>> >>> 1. Initialises the SMP mailbox area in the SCU at 0x1e6e2180 with default values >>> >>> 2. Copies a stub named 'mailbox_insn' from flash to the SCU, just above the >>> mailbox area >>> >>> 3. Sets AST_SMP_MBOX_FIELD_READY to a magic value to indicate the >>> secondary can begin execution from the stub >>> >>> 4. The stub waits until the AST_SMP_MBOX_FIELD_GOSIGN register is set to >>> a magic value >>> >>> 5. Jumps to the address in AST_SMP_MBOX_FIELD_ENTRY, starting Linux >>> >>> Linux indicates it is ready by writing the address of its entrypoint >>> function to AST_SMP_MBOX_FIELD_ENTRY and the 'go' magic number to >>> AST_SMP_MBOX_FIELD_GOSIGN. The secondary CPU sees this at step 4 and >>> breaks out of it's loop. >>> >>> To be compatible, a fixed qemu stub is loaded into the mailbox area. As >>> qemu can ensure the stub is loaded before execution starts, we do not >>> need to emulate the AST_SMP_MBOX_FIELD_READY behaviour of u-boot. The >>> secondary CPU's program counter points to the beginning of the stub, >>> allowing qemu to start secondaries at step four. >>> >>> Reboot behaviour is preserved by resetting AST_SMP_MBOX_FIELD_GOSIGN >>> when the secondaries are reset. >>> >>> This is only configured when the system is booted with -kernel and qemu >>> does not execute u-boot first. >>> >>> Signed-off-by: Joel Stanley <joel@jms.id.au> >>> --- >>> hw/arm/aspeed.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 65 insertions(+) >>> >>> diff --git a/hw/arm/aspeed.c b/hw/arm/aspeed.c >>> index a6a2102a93cb..bc4386cc6174 100644 >>> --- a/hw/arm/aspeed.c >>> +++ b/hw/arm/aspeed.c >>> @@ -116,6 +116,58 @@ static const MemoryRegionOps max_ram_ops = { >>> .endianness = DEVICE_NATIVE_ENDIAN, >>> }; >>> >>> +#define AST_SMP_MAILBOX_BASE 0x1e6e2180 >>> +#define AST_SMP_MBOX_FIELD_ENTRY (AST_SMP_MAILBOX_BASE + 0x0) >>> +#define AST_SMP_MBOX_FIELD_GOSIGN (AST_SMP_MAILBOX_BASE + 0x4) >>> +#define AST_SMP_MBOX_FIELD_READY (AST_SMP_MAILBOX_BASE + 0x8) >>> +#define AST_SMP_MBOX_FIELD_POLLINSN (AST_SMP_MAILBOX_BASE + 0xc) >>> +#define AST_SMP_MBOX_CODE (AST_SMP_MAILBOX_BASE + 0x10) >>> +#define AST_SMP_MBOX_GOSIGN 0xabbaab00 >>> + >>> +static void aspeed_write_smpboot(ARMCPU *cpu, >>> + const struct arm_boot_info *info) >>> +{ >>> + static const uint32_t poll_mailbox_ready[] = { >>> + /* >>> + * r2 = per-cpu go sign value >>> + * r1 = AST_SMP_MBOX_FIELD_ENTRY >>> + * r0 = AST_SMP_MBOX_FIELD_GOSIGN >>> + */ >>> + 0xee100fb0, /* mrc p15, 0, r0, c0, c0, 5 */ >>> + 0xe21000ff, /* ands r0, r0, #255 */ >>> + 0xe59f201c, /* ldr r2, [pc, #28] */ >>> + 0xe1822000, /* orr r2, r2, r0 */ >>> + >>> + 0xe59f1018, /* ldr r1, [pc, #24] */ >>> + 0xe59f0018, /* ldr r0, [pc, #24] */ >>> + >>> + 0xe320f002, /* wfe */ >>> + 0xe5904000, /* ldr r4, [r0] */ >>> + 0xe1520004, /* cmp r2, r4 */ >>> + 0x1afffffb, /* bne <wfe> */ >>> + 0xe591f000, /* ldr pc, [r1] */ >>> + AST_SMP_MBOX_GOSIGN, >>> + AST_SMP_MBOX_FIELD_ENTRY, >>> + AST_SMP_MBOX_FIELD_GOSIGN, >>> + }; >>> + >>> + rom_add_blob_fixed("aspeed.smpboot", poll_mailbox_ready, >>> + sizeof(poll_mailbox_ready), >>> + info->smp_loader_start); >>> +} >>> + >>> +static void aspeed_reset_secondary(ARMCPU *cpu, >>> + const struct arm_boot_info *info) >>> +{ >>> + AddressSpace *as = arm_boot_address_space(cpu, info); >>> + CPUState *cs = CPU(cpu); >>> + >>> + /* info->smp_bootreg_addr */ >>> + address_space_stl_notdirty(as, AST_SMP_MBOX_FIELD_GOSIGN, 0, >>> + MEMTXATTRS_UNSPECIFIED, NULL); >>> + cpu_set_pc(cs, info->smp_loader_start); >>> +} >>> + >>> #define FIRMWARE_ADDR 0x0 >>> >>> static void write_boot_rom(DriveInfo *dinfo, hwaddr addr, size_t rom_size, >>> @@ -270,6 +322,19 @@ static void aspeed_machine_init(MachineState *machine) >>> } >>> } >>> >>> + if (machine->kernel_filename) { >> >> I just realised this shouldn't be executed on non-ast2600 platforms. >> We could test for the number of CPUs like this: >> >> if (machine->kernel_filename && aspeed_board_binfo.nb_cpus > 1) { > > if (!strcmp(amc->soc_name, "ast2600")) { ? or a 'bool' under AspeedMachineClass ? A part from that, Reviewed-by: Cédric Le Goater <clg@kaod.org> Tested-by: Cédric Le Goater <clg@kaod.org> C. > >> >>> + /* With no u-boot we must set up a boot stub for the secondary CPU */ >>> + MemoryRegion *smpboot = g_new(MemoryRegion, 1); >>> + memory_region_init_ram(smpboot, OBJECT(bmc), "aspeed.smpboot", >>> + 0x80, &error_abort); >>> + memory_region_add_subregion(get_system_memory(), >>> + AST_SMP_MAILBOX_BASE, smpboot); >>> + >>> + aspeed_board_binfo.write_secondary_boot = aspeed_write_smpboot; >>> + aspeed_board_binfo.secondary_cpu_reset_hook = aspeed_reset_secondary; >>> + aspeed_board_binfo.smp_loader_start = AST_SMP_MBOX_CODE; >>> + } >>> + >>> aspeed_board_binfo.ram_size = ram_size; >>> aspeed_board_binfo.loader_start = sc->memmap[ASPEED_SDRAM]; >>> aspeed_board_binfo.nb_cpus = bmc->soc.num_cpus; >>> -- >>> 2.25.1 >>> >> >
On Tue, 7 Apr 2020 at 08:26, Cédric Le Goater <clg@kaod.org> wrote: > > On 4/7/20 10:19 AM, Philippe Mathieu-Daudé wrote: > > > > > > On 4/7/20 9:38 AM, Joel Stanley wrote: > >> On Tue, 7 Apr 2020 at 07:25, Joel Stanley <joel@jms.id.au> wrote: > >>> static void write_boot_rom(DriveInfo *dinfo, hwaddr addr, size_t rom_size, > >>> @@ -270,6 +322,19 @@ static void aspeed_machine_init(MachineState *machine) > >>> } > >>> } > >>> > >>> + if (machine->kernel_filename) { > >> > >> I just realised this shouldn't be executed on non-ast2600 platforms. > >> We could test for the number of CPUs like this: > >> > >> if (machine->kernel_filename && aspeed_board_binfo.nb_cpus > 1) { > > > > if (!strcmp(amc->soc_name, "ast2600")) { ? > > or a 'bool' under AspeedMachineClass ? I considered both, but I went with the number of configured CPUs as this means we only set it up when configured for SMP, which is the only time it's worth doing. Thanks for taking a look. > A part from that, > > Reviewed-by: Cédric Le Goater <clg@kaod.org> > Tested-by: Cédric Le Goater <clg@kaod.org> > > C. > > > > > >> > >>> + /* With no u-boot we must set up a boot stub for the secondary CPU */ > >>> + MemoryRegion *smpboot = g_new(MemoryRegion, 1); > >>> + memory_region_init_ram(smpboot, OBJECT(bmc), "aspeed.smpboot", > >>> + 0x80, &error_abort); > >>> + memory_region_add_subregion(get_system_memory(), > >>> + AST_SMP_MAILBOX_BASE, smpboot); > >>> + > >>> + aspeed_board_binfo.write_secondary_boot = aspeed_write_smpboot; > >>> + aspeed_board_binfo.secondary_cpu_reset_hook = aspeed_reset_secondary; > >>> + aspeed_board_binfo.smp_loader_start = AST_SMP_MBOX_CODE; > >>> + } > >>> + > >>> aspeed_board_binfo.ram_size = ram_size; > >>> aspeed_board_binfo.loader_start = sc->memmap[ASPEED_SDRAM]; > >>> aspeed_board_binfo.nb_cpus = bmc->soc.num_cpus; > >>> -- > >>> 2.25.1 > >>> > >> > > >
diff --git a/hw/arm/aspeed.c b/hw/arm/aspeed.c index a6a2102a93cb..bc4386cc6174 100644 --- a/hw/arm/aspeed.c +++ b/hw/arm/aspeed.c @@ -116,6 +116,58 @@ static const MemoryRegionOps max_ram_ops = { .endianness = DEVICE_NATIVE_ENDIAN, }; +#define AST_SMP_MAILBOX_BASE 0x1e6e2180 +#define AST_SMP_MBOX_FIELD_ENTRY (AST_SMP_MAILBOX_BASE + 0x0) +#define AST_SMP_MBOX_FIELD_GOSIGN (AST_SMP_MAILBOX_BASE + 0x4) +#define AST_SMP_MBOX_FIELD_READY (AST_SMP_MAILBOX_BASE + 0x8) +#define AST_SMP_MBOX_FIELD_POLLINSN (AST_SMP_MAILBOX_BASE + 0xc) +#define AST_SMP_MBOX_CODE (AST_SMP_MAILBOX_BASE + 0x10) +#define AST_SMP_MBOX_GOSIGN 0xabbaab00 + +static void aspeed_write_smpboot(ARMCPU *cpu, + const struct arm_boot_info *info) +{ + static const uint32_t poll_mailbox_ready[] = { + /* + * r2 = per-cpu go sign value + * r1 = AST_SMP_MBOX_FIELD_ENTRY + * r0 = AST_SMP_MBOX_FIELD_GOSIGN + */ + 0xee100fb0, /* mrc p15, 0, r0, c0, c0, 5 */ + 0xe21000ff, /* ands r0, r0, #255 */ + 0xe59f201c, /* ldr r2, [pc, #28] */ + 0xe1822000, /* orr r2, r2, r0 */ + + 0xe59f1018, /* ldr r1, [pc, #24] */ + 0xe59f0018, /* ldr r0, [pc, #24] */ + + 0xe320f002, /* wfe */ + 0xe5904000, /* ldr r4, [r0] */ + 0xe1520004, /* cmp r2, r4 */ + 0x1afffffb, /* bne <wfe> */ + 0xe591f000, /* ldr pc, [r1] */ + AST_SMP_MBOX_GOSIGN, + AST_SMP_MBOX_FIELD_ENTRY, + AST_SMP_MBOX_FIELD_GOSIGN, + }; + + rom_add_blob_fixed("aspeed.smpboot", poll_mailbox_ready, + sizeof(poll_mailbox_ready), + info->smp_loader_start); +} + +static void aspeed_reset_secondary(ARMCPU *cpu, + const struct arm_boot_info *info) +{ + AddressSpace *as = arm_boot_address_space(cpu, info); + CPUState *cs = CPU(cpu); + + /* info->smp_bootreg_addr */ + address_space_stl_notdirty(as, AST_SMP_MBOX_FIELD_GOSIGN, 0, + MEMTXATTRS_UNSPECIFIED, NULL); + cpu_set_pc(cs, info->smp_loader_start); +} + #define FIRMWARE_ADDR 0x0 static void write_boot_rom(DriveInfo *dinfo, hwaddr addr, size_t rom_size, @@ -270,6 +322,19 @@ static void aspeed_machine_init(MachineState *machine) } } + if (machine->kernel_filename) { + /* With no u-boot we must set up a boot stub for the secondary CPU */ + MemoryRegion *smpboot = g_new(MemoryRegion, 1); + memory_region_init_ram(smpboot, OBJECT(bmc), "aspeed.smpboot", + 0x80, &error_abort); + memory_region_add_subregion(get_system_memory(), + AST_SMP_MAILBOX_BASE, smpboot); + + aspeed_board_binfo.write_secondary_boot = aspeed_write_smpboot; + aspeed_board_binfo.secondary_cpu_reset_hook = aspeed_reset_secondary; + aspeed_board_binfo.smp_loader_start = AST_SMP_MBOX_CODE; + } + aspeed_board_binfo.ram_size = ram_size; aspeed_board_binfo.loader_start = sc->memmap[ASPEED_SDRAM]; aspeed_board_binfo.nb_cpus = bmc->soc.num_cpus;
This is a boot stub that is similar to the code u-boot runs, allowing the kernel to boot the secondary CPU. u-boot works as follows: 1. Initialises the SMP mailbox area in the SCU at 0x1e6e2180 with default values 2. Copies a stub named 'mailbox_insn' from flash to the SCU, just above the mailbox area 3. Sets AST_SMP_MBOX_FIELD_READY to a magic value to indicate the secondary can begin execution from the stub 4. The stub waits until the AST_SMP_MBOX_FIELD_GOSIGN register is set to a magic value 5. Jumps to the address in AST_SMP_MBOX_FIELD_ENTRY, starting Linux Linux indicates it is ready by writing the address of its entrypoint function to AST_SMP_MBOX_FIELD_ENTRY and the 'go' magic number to AST_SMP_MBOX_FIELD_GOSIGN. The secondary CPU sees this at step 4 and breaks out of it's loop. To be compatible, a fixed qemu stub is loaded into the mailbox area. As qemu can ensure the stub is loaded before execution starts, we do not need to emulate the AST_SMP_MBOX_FIELD_READY behaviour of u-boot. The secondary CPU's program counter points to the beginning of the stub, allowing qemu to start secondaries at step four. Reboot behaviour is preserved by resetting AST_SMP_MBOX_FIELD_GOSIGN when the secondaries are reset. This is only configured when the system is booted with -kernel and qemu does not execute u-boot first. Signed-off-by: Joel Stanley <joel@jms.id.au> --- hw/arm/aspeed.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+)