sbsa-uart is a virtual UART device with a sub-set of PL011 functionality which is described in SBSA (Server Base System Architecture)[1].
It mainly targets for server use, but sbsa-uart itself is useful in any para-virtualized use cases, including Xen.
At present, this patch is submitted as RFC because: * for some reason, data cache must be turned off (in initr_dcache()) * there is a prerequisite patch for Xen[2]
The patch with xenguest_arm64_defconfig was tested on upstream Xen and qemu-arm64. (To work with xenguest_arm64_defconfig, minor and non-essential tweaks are needed.)
The output looks like: U-Boot 2021.01-rc1-00005-g3b8e3cde5345 (Nov 04 2020 - 13:54:44 +0900) xenguest
Xen virtual CPU Model: XENVM-4.15 DRAM: 128 MiB PVBLOCK: Failed to read device/vbd directory: ENOENT
In: sbsa-pl011 Out: sbsa-pl011 Err: sbsa-pl011 xenguest# dm tree Class Index Probed Driver Name ----------------------------------------------------------- root 0 [ + ] root_driver root_driver firmware 0 [ ] psci |-- psci serial 0 [ + ] serial_pl01x |-- sbsa-pl011 pvblock 0 [ ] pvblock `-- pvblock
[1] https://developer.arm.com/architectures/platform-design/server-systems [2] https://lists.xenproject.org/archives/html/xen-devel/2020-10/msg02122.html
Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org --- drivers/serial/Kconfig | 13 +++++++++++-- drivers/serial/serial_pl01x.c | 16 +++++++++++++--- include/dm/platform_data/serial_pl01x.h | 1 + 3 files changed, 25 insertions(+), 5 deletions(-)
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig index b4805a2e4ea4..fb570174c577 100644 --- a/drivers/serial/Kconfig +++ b/drivers/serial/Kconfig @@ -332,6 +332,15 @@ config DEBUG_UART_PL011 work. The driver will be available until the real driver model serial is running.
+config DEBUG_UART_SBSA + bool "sbsa-uart" + depends on PL01X_SERIAL + help + Select this to enable a debug UART using the pl01x driver with the + SBSA_UART type. You will need to provide parameters to make this + work. The driver will be available until the real driver model + serial is running. + config DEBUG_UART_PIC32 bool "Microchip PIC32" depends on PIC32_SERIAL @@ -415,7 +424,7 @@ config DEBUG_UART_BASE
config DEBUG_UART_CLOCK int "UART input clock" - depends on DEBUG_UART + depends on DEBUG_UART && !DEBUG_UART_SBSA default 0 if DEBUG_UART_SANDBOX help The UART input clock determines the speed of the internal UART @@ -427,7 +436,7 @@ config DEBUG_UART_CLOCK
config DEBUG_UART_SHIFT int "UART register shift" - depends on DEBUG_UART + depends on DEBUG_UART && !DEBUG_UART_SBSA default 0 if DEBUG_UART help Some UARTs (notably ns16550) support different register layouts diff --git a/drivers/serial/serial_pl01x.c b/drivers/serial/serial_pl01x.c index 2772c25f1d2d..5ef4ae0c6a65 100644 --- a/drivers/serial/serial_pl01x.c +++ b/drivers/serial/serial_pl01x.c @@ -84,6 +84,8 @@ static int pl01x_generic_serial_init(struct pl01x_regs *regs, /* disable everything */ writel(0, ®s->pl011_cr); break; + case TYPE_SBSA_UART: + break; default: return -EINVAL; } @@ -146,7 +148,8 @@ static int pl01x_generic_setbrg(struct pl01x_regs *regs, enum pl01x_type type, writel(UART_PL010_CR_UARTEN, ®s->pl010_cr); break; } - case TYPE_PL011: { + case TYPE_PL011: + case TYPE_SBSA_UART: { unsigned int temp; unsigned int divider; unsigned int remainder; @@ -171,6 +174,9 @@ static int pl01x_generic_setbrg(struct pl01x_regs *regs, enum pl01x_type type, writel(fraction, ®s->pl011_fbrd); }
+ if (type == TYPE_SBSA_UART) + break; + pl011_set_line_control(regs); /* Finally, enable the UART */ writel(UART_PL011_CR_UARTEN | UART_PL011_CR_TXE | @@ -340,6 +346,7 @@ static const struct dm_serial_ops pl01x_serial_ops = { static const struct udevice_id pl01x_serial_id[] ={ {.compatible = "arm,pl011", .data = TYPE_PL011}, {.compatible = "arm,pl010", .data = TYPE_PL010}, + {.compatible = "arm,sbsa-uart", .data = TYPE_SBSA_UART}, {} };
@@ -386,7 +393,8 @@ U_BOOT_DRIVER(serial_pl01x) = {
#endif
-#if defined(CONFIG_DEBUG_UART_PL010) || defined(CONFIG_DEBUG_UART_PL011) +#if defined(CONFIG_DEBUG_UART_PL010) || defined(CONFIG_DEBUG_UART_PL011) || \ + defined(CONFIG_DEBUG_UART_SBSA)
#include <debug_uart.h>
@@ -395,7 +403,9 @@ static void _debug_uart_init(void) #ifndef CONFIG_DEBUG_UART_SKIP_INIT struct pl01x_regs *regs = (struct pl01x_regs *)CONFIG_DEBUG_UART_BASE; enum pl01x_type type = CONFIG_IS_ENABLED(DEBUG_UART_PL011) ? - TYPE_PL011 : TYPE_PL010; + TYPE_PL011 : + (CONFIG_IS_ENABLED(DEBUG_UART_PL010) ? + TYPE_PL010 : TYPE_SBSA_UART);
pl01x_generic_serial_init(regs, type); pl01x_generic_setbrg(regs, type, diff --git a/include/dm/platform_data/serial_pl01x.h b/include/dm/platform_data/serial_pl01x.h index 77d96c49f03a..4bacbd512400 100644 --- a/include/dm/platform_data/serial_pl01x.h +++ b/include/dm/platform_data/serial_pl01x.h @@ -9,6 +9,7 @@ enum pl01x_type { TYPE_PL010, TYPE_PL011, + TYPE_SBSA_UART, };
/*