lib: sbi: Implement SBI debug console extension

We implement SBI debug console extension as one of the replacement
SBI extensions. This extension is only available when OpenSBI platform
provides a console device to generic library.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Bin Meng <bmeng@tinylab.org>
This commit is contained in:
Anup Patel 2022-11-23 11:11:43 +05:30 committed by Anup Patel
parent eab48c33a1
commit 5a41a3884f
3 changed files with 79 additions and 0 deletions

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@ -26,6 +26,10 @@ config SBI_ECALL_PMU
bool "Performance Monitoring Unit extension"
default y
config SBI_ECALL_DBCN
bool "Debug Console extension"
default y
config SBI_ECALL_LEGACY
bool "SBI v0.1 legacy extensions"
default y

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@ -37,6 +37,9 @@ libsbi-objs-$(CONFIG_SBI_ECALL_SRST) += sbi_ecall_srst.o
carray-sbi_ecall_exts-$(CONFIG_SBI_ECALL_PMU) += ecall_pmu
libsbi-objs-$(CONFIG_SBI_ECALL_PMU) += sbi_ecall_pmu.o
carray-sbi_ecall_exts-$(CONFIG_SBI_ECALL_DBCN) += ecall_dbcn
libsbi-objs-$(CONFIG_SBI_ECALL_DBCN) += sbi_ecall_dbcn.o
carray-sbi_ecall_exts-$(CONFIG_SBI_ECALL_LEGACY) += ecall_legacy
libsbi-objs-$(CONFIG_SBI_ECALL_LEGACY) += sbi_ecall_legacy.o

72
lib/sbi/sbi_ecall_dbcn.c Normal file
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@ -0,0 +1,72 @@
/*
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2022 Ventana Micro Systems Inc.
*
* Authors:
* Anup Patel <apatel@ventanamicro.com>
*/
#include <sbi/sbi_console.h>
#include <sbi/sbi_domain.h>
#include <sbi/sbi_error.h>
#include <sbi/sbi_ecall.h>
#include <sbi/sbi_ecall_interface.h>
#include <sbi/sbi_trap.h>
#include <sbi/riscv_asm.h>
static int sbi_ecall_dbcn_handler(unsigned long extid, unsigned long funcid,
const struct sbi_trap_regs *regs,
unsigned long *out_val,
struct sbi_trap_info *out_trap)
{
ulong smode = (csr_read(CSR_MSTATUS) & MSTATUS_MPP) >>
MSTATUS_MPP_SHIFT;
switch (funcid) {
case SBI_EXT_DBCN_CONSOLE_WRITE:
case SBI_EXT_DBCN_CONSOLE_READ:
/*
* On RV32, the M-mode can only access the first 4GB of
* the physical address space because M-mode does not have
* MMU to access full 34-bit physical address space.
*
* Based on above, we simply fail if the upper 32bits of
* the physical address (i.e. a2 register) is non-zero on
* RV32.
*/
#if __riscv_xlen == 32
if (regs->a2)
return SBI_ERR_FAILED;
#endif
if (!sbi_domain_check_addr_range(sbi_domain_thishart_ptr(),
regs->a1, regs->a0, smode,
SBI_DOMAIN_READ|SBI_DOMAIN_WRITE))
return SBI_ERR_INVALID_PARAM;
if (funcid == SBI_EXT_DBCN_CONSOLE_WRITE)
*out_val = sbi_nputs((const char *)regs->a1, regs->a0);
else
*out_val = sbi_ngets((char *)regs->a1, regs->a0);
return 0;
case SBI_EXT_DBCN_CONSOLE_WRITE_BYTE:
sbi_putc(regs->a0);
return 0;
default:
break;
}
return SBI_ENOTSUPP;
}
static int sbi_ecall_dbcn_probe(unsigned long extid, unsigned long *out_val)
{
*out_val = sbi_console_get_device() ? 1 : 0;
return 0;
}
struct sbi_ecall_extension ecall_dbcn = {
.extid_start = SBI_EXT_DBCN,
.extid_end = SBI_EXT_DBCN,
.handle = sbi_ecall_dbcn_handler,
.probe = sbi_ecall_dbcn_probe,
};