| Message ID | 20200925113057.725911-1-anup.patel@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RFC] RISC-V: Use SBI SRST extension when available | expand |
> -----Original Message----- > From: Anup Patel <Anup.Patel@wdc.com> > Sent: 25 September 2020 17:01 > To: Palmer Dabbelt <palmer@dabbelt.com>; Palmer Dabbelt > <palmerdabbelt@google.com>; Paul Walmsley <paul.walmsley@sifive.com>; > Albert Ou <aou@eecs.berkeley.edu> > Cc: Atish Patra <Atish.Patra@wdc.com>; Alistair Francis > <Alistair.Francis@wdc.com>; Anup Patel <anup@brainfault.org>; linux- > riscv@lists.infradead.org; linux-kernel@vger.kernel.org; Anup Patel > <Anup.Patel@wdc.com> > Subject: [RFC PATCH] RISC-V: Use SBI SRST extension when available > > The SBI SRST extension provides a standard way to poweroff and reboot the > system irrespective to whether Linux RISC-V S-mode is running natively (HS- > mode) or inside Guest/VM (VS-mode). > > The draft specification of SBI SRST extension is available in > srbt_v1 branch of: https://github.com/avpatel/riscv-sbi-doc. > > This patch extends Linux RISC-V SBI implementation to detect and use SBI > SRST extension. > > Signed-off-by: Anup Patel <anup.patel@wdc.com> > --- > arch/riscv/include/asm/sbi.h | 7 +++++++ > arch/riscv/kernel/sbi.c | 25 +++++++++++++++++++++++++ > 2 files changed, 32 insertions(+) > > diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h index > 653edb25d495..2fcecec7dd0c 100644 > --- a/arch/riscv/include/asm/sbi.h > +++ b/arch/riscv/include/asm/sbi.h > @@ -27,6 +27,7 @@ enum sbi_ext_id { > SBI_EXT_IPI = 0x735049, > SBI_EXT_RFENCE = 0x52464E43, > SBI_EXT_HSM = 0x48534D, > + SBI_EXT_SRST = 0x53525354, > }; > > enum sbi_ext_base_fid { > @@ -70,6 +71,12 @@ enum sbi_hsm_hart_status { > SBI_HSM_HART_STATUS_STOP_PENDING, > }; > > +enum sbi_ext_srst_fid { > + SBI_EXT_SRST_SHUTDOWN = 0, > + SBI_EXT_SRST_COLD_REBOOT, > + SBI_EXT_SRST_WARM_REBOOT > +}; > + I referred older SBI SRST extension draft where we have separate function ID for shutdown, cold reboot, and warm reboot. I will send v2 patch as-per latest SBI SRST extension draft. My apologies for the noise. Regards, Anup > #define SBI_SPEC_VERSION_DEFAULT 0x1 > #define SBI_SPEC_VERSION_MAJOR_SHIFT 24 > #define SBI_SPEC_VERSION_MAJOR_MASK 0x7f > diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index > 226ccce0f9e0..865e028a9a4b 100644 > --- a/arch/riscv/kernel/sbi.c > +++ b/arch/riscv/kernel/sbi.c > @@ -7,6 +7,7 @@ > > #include <linux/init.h> > #include <linux/pm.h> > +#include <linux/reboot.h> > #include <asm/sbi.h> > #include <asm/smp.h> > > @@ -501,6 +502,23 @@ int sbi_remote_hfence_vvma_asid(const unsigned > long *hart_mask, } EXPORT_SYMBOL(sbi_remote_hfence_vvma_asid); > > +static int sbi_srst_reboot(struct notifier_block *this, > + unsigned long mode, void *cmd) > +{ > + sbi_ecall(SBI_EXT_SRST, (mode == REBOOT_WARM || mode == > REBOOT_SOFT) ? > + SBI_EXT_SRST_WARM_REBOOT : > SBI_EXT_SRST_COLD_REBOOT, > + 0, 0, 0, 0, 0, 0); > + > + return NOTIFY_DONE; > +} > + > +static struct notifier_block sbi_srst_reboot_nb; > + > +static void sbi_srst_power_off(void) > +{ > + sbi_ecall(SBI_EXT_SRST, SBI_EXT_SRST_SHUTDOWN, 0, 0, 0, 0, 0, 0); } > + > /** > * sbi_probe_extension() - Check if an SBI extension ID is supported or not. > * @extid: The extension ID to be probed. > @@ -593,6 +611,13 @@ int __init sbi_init(void) > } else { > __sbi_rfence = __sbi_rfence_v01; > } > + if (sbi_probe_extension(SBI_EXT_SRST) > 0) { > + pr_info("SBI v0.2 SRST extension detected\n"); > + pm_power_off = sbi_srst_power_off; > + sbi_srst_reboot_nb.notifier_call = sbi_srst_reboot; > + sbi_srst_reboot_nb.priority = 192; > + register_restart_handler(&sbi_srst_reboot_nb); > + } > } else { > __sbi_set_timer = __sbi_set_timer_v01; > __sbi_send_ipi = __sbi_send_ipi_v01; > -- > 2.25.1
diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h index 653edb25d495..2fcecec7dd0c 100644 --- a/arch/riscv/include/asm/sbi.h +++ b/arch/riscv/include/asm/sbi.h @@ -27,6 +27,7 @@ enum sbi_ext_id { SBI_EXT_IPI = 0x735049, SBI_EXT_RFENCE = 0x52464E43, SBI_EXT_HSM = 0x48534D, + SBI_EXT_SRST = 0x53525354, }; enum sbi_ext_base_fid { @@ -70,6 +71,12 @@ enum sbi_hsm_hart_status { SBI_HSM_HART_STATUS_STOP_PENDING, }; +enum sbi_ext_srst_fid { + SBI_EXT_SRST_SHUTDOWN = 0, + SBI_EXT_SRST_COLD_REBOOT, + SBI_EXT_SRST_WARM_REBOOT +}; + #define SBI_SPEC_VERSION_DEFAULT 0x1 #define SBI_SPEC_VERSION_MAJOR_SHIFT 24 #define SBI_SPEC_VERSION_MAJOR_MASK 0x7f diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index 226ccce0f9e0..865e028a9a4b 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -7,6 +7,7 @@ #include <linux/init.h> #include <linux/pm.h> +#include <linux/reboot.h> #include <asm/sbi.h> #include <asm/smp.h> @@ -501,6 +502,23 @@ int sbi_remote_hfence_vvma_asid(const unsigned long *hart_mask, } EXPORT_SYMBOL(sbi_remote_hfence_vvma_asid); +static int sbi_srst_reboot(struct notifier_block *this, + unsigned long mode, void *cmd) +{ + sbi_ecall(SBI_EXT_SRST, (mode == REBOOT_WARM || mode == REBOOT_SOFT) ? + SBI_EXT_SRST_WARM_REBOOT : SBI_EXT_SRST_COLD_REBOOT, + 0, 0, 0, 0, 0, 0); + + return NOTIFY_DONE; +} + +static struct notifier_block sbi_srst_reboot_nb; + +static void sbi_srst_power_off(void) +{ + sbi_ecall(SBI_EXT_SRST, SBI_EXT_SRST_SHUTDOWN, 0, 0, 0, 0, 0, 0); +} + /** * sbi_probe_extension() - Check if an SBI extension ID is supported or not. * @extid: The extension ID to be probed. @@ -593,6 +611,13 @@ int __init sbi_init(void) } else { __sbi_rfence = __sbi_rfence_v01; } + if (sbi_probe_extension(SBI_EXT_SRST) > 0) { + pr_info("SBI v0.2 SRST extension detected\n"); + pm_power_off = sbi_srst_power_off; + sbi_srst_reboot_nb.notifier_call = sbi_srst_reboot; + sbi_srst_reboot_nb.priority = 192; + register_restart_handler(&sbi_srst_reboot_nb); + } } else { __sbi_set_timer = __sbi_set_timer_v01; __sbi_send_ipi = __sbi_send_ipi_v01;
The SBI SRST extension provides a standard way to poweroff and reboot the system irrespective to whether Linux RISC-V S-mode is running natively (HS-mode) or inside Guest/VM (VS-mode). The draft specification of SBI SRST extension is available in srbt_v1 branch of: https://github.com/avpatel/riscv-sbi-doc. This patch extends Linux RISC-V SBI implementation to detect and use SBI SRST extension. Signed-off-by: Anup Patel <anup.patel@wdc.com> --- arch/riscv/include/asm/sbi.h | 7 +++++++ arch/riscv/kernel/sbi.c | 25 +++++++++++++++++++++++++ 2 files changed, 32 insertions(+)