Unverified Commit 951df4eb authored by Palmer Dabbelt's avatar Palmer Dabbelt
Browse files

Merge patch series "RISC-V SBI debug console extension support" 

Anup Patel <apatel@ventanamicro.com> says:

The SBI v2.0 specification is now frozen. The SBI v2.0 specification defines
SBI debug console (DBCN) extension which replaces the legacy SBI v0.1
functions sbi_console_putchar() and sbi_console_getchar().
(Refer v2.0-rc5 at https://github.com/riscv-non-isa/riscv-sbi-doc/releases)

This series adds support for SBI debug console (DBCN) extension in
Linux RISC-V.

To try these patches with KVM RISC-V, use KVMTOOL from the
riscv_zbx_zicntr_smstateen_condops_v1 branch at:
https://github.com/avpatel/kvmtool.git

* b4-shazam-merge:
  RISC-V: Enable SBI based earlycon support
  tty: Add SBI debug console support to HVC SBI driver
  tty/serial: Add RISC-V SBI debug console based earlycon
  RISC-V: Add SBI debug console helper routines
  RISC-V: Add stubs for sbi_console_putchar/getchar()

Link: https://lore.kernel.org/r/20231124070905.1043092-1-apatel@ventanamicro.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parents 4dc4af9c 50942ad6

arch/riscv/configs/defconfig

+1 −0
Original line number Diff line number Diff line
@@ -149,6 +149,7 @@ CONFIG_SERIAL_8250_CONSOLE=y 
CONFIG_SERIAL_8250_DW=y

CONFIG_SERIAL_OF_PLATFORM=y

CONFIG_SERIAL_SH_SCI=y

CONFIG_SERIAL_EARLYCON_RISCV_SBI=y

CONFIG_VIRTIO_CONSOLE=y

CONFIG_HW_RANDOM=y

CONFIG_HW_RANDOM_VIRTIO=y

arch/riscv/include/asm/sbi.h

+10 −0
Original line number Diff line number Diff line
@@ -280,8 +280,13 @@ struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0, 
			unsigned long arg3, unsigned long arg4,

			unsigned long arg5);



#ifdef CONFIG_RISCV_SBI_V01

void sbi_console_putchar(int ch);

int sbi_console_getchar(void);

#else

static inline void sbi_console_putchar(int ch) { }

static inline int sbi_console_getchar(void) { return -ENOENT; }

#endif

long sbi_get_mvendorid(void);

long sbi_get_marchid(void);

long sbi_get_mimpid(void);
@@ -338,6 +343,11 @@ 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(const char *bytes, unsigned int num_bytes);

int sbi_debug_console_read(char *bytes, unsigned int num_bytes);



#else /* CONFIG_RISCV_SBI */

static inline int sbi_remote_fence_i(const struct cpumask *cpu_mask) { return -1; }

static inline void sbi_init(void) {}

arch/riscv/kernel/sbi.c

+66 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 


#include <linux/bits.h>

#include <linux/init.h>

#include <linux/mm.h>

#include <linux/pm.h>

#include <linux/reboot.h>

#include <asm/sbi.h>
@@ -571,6 +572,66 @@ long sbi_get_mimpid(void) 
}

EXPORT_SYMBOL_GPL(sbi_get_mimpid);



bool sbi_debug_console_available;



int sbi_debug_console_write(const char *bytes, unsigned int num_bytes)

{

	phys_addr_t base_addr;

	struct sbiret ret;



	if (!sbi_debug_console_available)

		return -EOPNOTSUPP;



	if (is_vmalloc_addr(bytes))

		base_addr = page_to_phys(vmalloc_to_page(bytes)) +

			    offset_in_page(bytes);

	else

		base_addr = __pa(bytes);

	if (PAGE_SIZE < (offset_in_page(bytes) + num_bytes))

		num_bytes = PAGE_SIZE - offset_in_page(bytes);



	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);



	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(char *bytes, unsigned int num_bytes)

{

	phys_addr_t base_addr;

	struct sbiret ret;



	if (!sbi_debug_console_available)

		return -EOPNOTSUPP;



	if (is_vmalloc_addr(bytes))

		base_addr = page_to_phys(vmalloc_to_page(bytes)) +

			    offset_in_page(bytes);

	else

		base_addr = __pa(bytes);

	if (PAGE_SIZE < (offset_in_page(bytes) + num_bytes))

		num_bytes = PAGE_SIZE - offset_in_page(bytes);



	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);



	if (ret.error == SBI_ERR_FAILURE)

		return -EIO;

	return ret.error ? sbi_err_map_linux_errno(ret.error) : ret.value;

}



void __init sbi_init(void)

{

	int ret;
@@ -612,6 +673,11 @@ 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;

drivers/tty/hvc/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -108,7 +108,7 @@ config HVC_DCC_SERIALIZE_SMP 


config HVC_RISCV_SBI

	bool "RISC-V SBI console support"

	depends on RISCV_SBI_V01

	depends on RISCV_SBI

	select HVC_DRIVER

	help

	  This enables support for console output via RISC-V SBI calls, which

drivers/tty/hvc/hvc_riscv_sbi.c

+30 −7
Original line number Diff line number Diff line
@@ -39,21 +39,44 @@ static int hvc_sbi_tty_get(uint32_t vtermno, char *buf, int count) 
	return i;

}



static const struct hv_ops hvc_sbi_ops = {

static const struct hv_ops hvc_sbi_v01_ops = {

	.get_chars = hvc_sbi_tty_get,

	.put_chars = hvc_sbi_tty_put,

};



static int __init hvc_sbi_init(void)

static int hvc_sbi_dbcn_tty_put(uint32_t vtermno, const char *buf, int count)

{

	return PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_ops, 16));

	return sbi_debug_console_write(buf, count);

}

device_initcall(hvc_sbi_init);



static int __init hvc_sbi_console_init(void)

static int hvc_sbi_dbcn_tty_get(uint32_t vtermno, char *buf, int count)

{

	hvc_instantiate(0, 0, &hvc_sbi_ops);

	return sbi_debug_console_read(buf, count);

}



static const struct hv_ops hvc_sbi_dbcn_ops = {

	.put_chars = hvc_sbi_dbcn_tty_put,

	.get_chars = hvc_sbi_dbcn_tty_get,

};



static int __init hvc_sbi_init(void)

{

	int err;



	if (sbi_debug_console_available) {

		err = PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_dbcn_ops, 256));

		if (err)

			return err;

		hvc_instantiate(0, 0, &hvc_sbi_dbcn_ops);

	} else if (IS_ENABLED(CONFIG_RISCV_SBI_V01)) {

		err = PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_v01_ops, 256));

		if (err)

			return err;

		hvc_instantiate(0, 0, &hvc_sbi_v01_ops);

	} else {

		return -ENODEV;

	}



	return 0;

}

console_initcall(hvc_sbi_console_init);
 
device_initcall(hvc_sbi_init);