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[31.30.173.16]) by smtp.gmail.com with ESMTPSA id j7-20020a05600c190700b004064cd71aa8sm12586581wmq.34.2023.11.20.00.05.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Nov 2023 00:05:18 -0800 (PST) Date: Mon, 20 Nov 2023 09:05:17 +0100 From: Andrew Jones To: Anup Patel Cc: Palmer Dabbelt , Paul Walmsley , Greg Kroah-Hartman , Jiri Slaby , Conor Dooley , linux-riscv@lists.infradead.org, linux-serial@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 2/5] RISC-V: Add SBI debug console helper routines Message-ID: <20231120-639982716fbfd33a6fc144d6@orel> References: <20231118033859.726692-1-apatel@ventanamicro.com> <20231118033859.726692-3-apatel@ventanamicro.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231118033859.726692-3-apatel@ventanamicro.com> Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On Sat, Nov 18, 2023 at 09:08:56AM +0530, Anup Patel wrote: > Let us provide SBI debug console helper routines which can be > shared by serial/earlycon-riscv-sbi.c and hvc/hvc_riscv_sbi.c. > > Signed-off-by: Anup Patel > --- > arch/riscv/include/asm/sbi.h | 5 +++++ > arch/riscv/kernel/sbi.c | 43 ++++++++++++++++++++++++++++++++++++ > 2 files changed, 48 insertions(+) > > diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h > index 66f3933c14f6..ee7aef5f6233 100644 > --- a/arch/riscv/include/asm/sbi.h > +++ b/arch/riscv/include/asm/sbi.h > @@ -334,6 +334,11 @@ static inline unsigned long sbi_mk_version(unsigned long major, > } > > int sbi_err_map_linux_errno(int err); > + > +extern bool sbi_debug_console_available; > +int sbi_debug_console_write(unsigned int num_bytes, phys_addr_t base_addr); > +int sbi_debug_console_read(unsigned int num_bytes, phys_addr_t base_addr); > + > #else /* CONFIG_RISCV_SBI */ > static inline int sbi_remote_fence_i(const struct cpumask *cpu_mask) { return -1; } > static inline void sbi_init(void) {} > diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c > index 5a62ed1da453..73a9c22c3945 100644 > --- a/arch/riscv/kernel/sbi.c > +++ b/arch/riscv/kernel/sbi.c > @@ -571,6 +571,44 @@ long sbi_get_mimpid(void) > } > EXPORT_SYMBOL_GPL(sbi_get_mimpid); > > +bool sbi_debug_console_available; > + > +int sbi_debug_console_write(unsigned int num_bytes, phys_addr_t base_addr) > +{ > + struct sbiret ret; > + > + if (!sbi_debug_console_available) > + return -EOPNOTSUPP; > + > + if (IS_ENABLED(CONFIG_32BIT)) > + ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_WRITE, > + num_bytes, lower_32_bits(base_addr), > + upper_32_bits(base_addr), 0, 0, 0); > + else > + ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_WRITE, > + num_bytes, base_addr, 0, 0, 0, 0); > + > + return ret.error ? sbi_err_map_linux_errno(ret.error) : ret.value; We can't get perfect mappings, but I wonder if we can do better than returning ENOTSUPP for "Failed to write the byte due to I/O errors." How about if (ret.error == SBI_ERR_FAILURE) return -EIO; return ret.error ? sbi_err_map_linux_errno(ret.error) : ret.value; > +} > + > +int sbi_debug_console_read(unsigned int num_bytes, phys_addr_t base_addr) > +{ > + struct sbiret ret; > + > + if (!sbi_debug_console_available) > + return -EOPNOTSUPP; > + > + if (IS_ENABLED(CONFIG_32BIT)) > + ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_READ, > + num_bytes, lower_32_bits(base_addr), > + upper_32_bits(base_addr), 0, 0, 0); > + else > + ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_READ, > + num_bytes, base_addr, 0, 0, 0, 0); > + > + return ret.error ? sbi_err_map_linux_errno(ret.error) : ret.value; Same comment as above. > +} > + > void __init sbi_init(void) > { > int ret; > @@ -612,6 +650,11 @@ void __init sbi_init(void) > sbi_srst_reboot_nb.priority = 192; > register_restart_handler(&sbi_srst_reboot_nb); > } > + if ((sbi_spec_version >= sbi_mk_version(2, 0)) && > + (sbi_probe_extension(SBI_EXT_DBCN) > 0)) { > + pr_info("SBI DBCN extension detected\n"); > + sbi_debug_console_available = true; > + } > } else { > __sbi_set_timer = __sbi_set_timer_v01; > __sbi_send_ipi = __sbi_send_ipi_v01; > -- > 2.34.1 > Otherwise, Reviewed-by: Andrew Jones Thanks, drew