Re: [PATCH v2 7/8] tty: Add SBI debug console support to HVC SBI driver
From: Björn Töpel <bjorn@kernel.org>
Date: 2023-10-12 11:38:55
Also in:
kvm, kvm-riscv, linux-riscv, linux-serial, lkml
Anup Patel [off-list ref] writes:
quoted hunk ↗ jump to hunk
From: Atish Patra <redacted> RISC-V SBI specification supports advanced debug console support via SBI DBCN extension. Extend the HVC SBI driver to support it. Signed-off-by: Atish Patra <redacted> Signed-off-by: Anup Patel <redacted> --- drivers/tty/hvc/Kconfig | 2 +- drivers/tty/hvc/hvc_riscv_sbi.c | 76 ++++++++++++++++++++++++++++++--- 2 files changed, 70 insertions(+), 8 deletions(-)diff --git a/drivers/tty/hvc/Kconfig b/drivers/tty/hvc/Kconfig index 4f9264d005c0..6e05c5c7bca1 100644 --- a/drivers/tty/hvc/Kconfig +++ b/drivers/tty/hvc/Kconfig@@ -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, whichdiff --git a/drivers/tty/hvc/hvc_riscv_sbi.c b/drivers/tty/hvc/hvc_riscv_sbi.c index 31f53fa77e4a..da318d7f55c5 100644 --- a/drivers/tty/hvc/hvc_riscv_sbi.c +++ b/drivers/tty/hvc/hvc_riscv_sbi.c@@ -39,21 +39,83 @@ 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)); + phys_addr_t pa; + struct sbiret ret; + + if (is_vmalloc_addr(buf)) + pa = page_to_phys(vmalloc_to_page(buf)) + offset_in_page(buf);
What is assumed from buf here? If buf is crossing a page, you need to adjust the count, no?
+ else
+ pa = __pa(buf);
+
+ if (IS_ENABLED(CONFIG_32BIT))
+ ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_WRITE,
+ count, lower_32_bits(pa), upper_32_bits(pa),
+ 0, 0, 0);
+ else
+ ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_WRITE,
+ count, pa, 0, 0, 0, 0);
+ if (ret.error)
+ return 0;
+
+ return 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);
+ phys_addr_t pa;
+ struct sbiret ret;
+
+ if (is_vmalloc_addr(buf))
+ pa = page_to_phys(vmalloc_to_page(buf)) + offset_in_page(buf);And definitely adjust count here, if we're crossing a page! Björn