On Sun, May 19, 2024 at 1:53 PM Jiaxun Yang <[email protected]> wrote: > > Add xtensa semihosting driver. > > It can't use regular semihosting driver as Xtensa's has it's own > semihosting ABI. > > Note that semihosting supports puts in serial but I never managed to > get it work, so it's putc only for now.
I wonder, what were the issues that you experienced? > Signed-off-by: Jiaxun Yang <[email protected]> > --- > drivers/serial/Kconfig | 18 ++++++- > drivers/serial/Makefile | 1 + > drivers/serial/serial_xtensa_semihosting.c | 79 > ++++++++++++++++++++++++++++++ > 3 files changed, 97 insertions(+), 1 deletion(-) > > diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig > index 1fe4607598eb..3a1e5a6f2877 100644 > --- a/drivers/serial/Kconfig > +++ b/drivers/serial/Kconfig > @@ -501,6 +501,15 @@ config DEBUG_UART_MT7620 > driver will be available until the real driver model serial is > running. > > +config DEBUG_UART_XTENSA_SEMIHOSTING > + bool "Xtensa semihosting" > + depends on XTENSA_SEMIHOSTING_SERIAL > + help > + Select this to enable the debug UART using the Xtensa semihosting > driver. > + This provides basic serial output from the console without needing > to > + start up driver model. The driver will be available until the real > + driver model serial is running. > + > endchoice > > config DEBUG_UART_BASE > @@ -936,7 +945,6 @@ config SH_SCIF_CLK_FREQ > config SEMIHOSTING_SERIAL > bool "Semihosting UART support" > depends on SEMIHOSTING && !SERIAL_RX_BUFFER > - imply SERIAL_PUTS > help > Select this to enable a serial UART using semihosting. Special halt > instructions will be issued which an external debugger (such as a > @@ -1115,6 +1123,14 @@ config XEN_SERIAL > If built without DM support, then requires Xen > to be built with CONFIG_VERBOSE_DEBUG. > > +config XTENSA_SEMIHOSTING_SERIAL > + bool "Xtensa Semihosting UART support" > + depends on DM_SERIAL > + depends on XTENSA_SEMIHOSTING > + imply SERIAL_PUTS > + help > + Select this to enable a serial UART using Xtensa semihosting. > + > choice > prompt "Console port" > default 8xx_CONS_SMC1 > diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile > index dbe598b74064..78810f98367c 100644 > --- a/drivers/serial/Makefile > +++ b/drivers/serial/Makefile > @@ -60,6 +60,7 @@ obj-$(CONFIG_MT7620_SERIAL) += serial_mt7620.o > obj-$(CONFIG_HTIF_CONSOLE) += serial_htif.o > obj-$(CONFIG_SIFIVE_SERIAL) += serial_sifive.o > obj-$(CONFIG_XEN_SERIAL) += serial_xen.o > +obj-$(CONFIG_XTENSA_SEMIHOSTING_SERIAL) += serial_xtensa_semihosting.o > obj-$(CONFIG_S5P4418_PL011_SERIAL) += serial_s5p4418_pl011.o > > ifndef CONFIG_SPL_BUILD > diff --git a/drivers/serial/serial_xtensa_semihosting.c > b/drivers/serial/serial_xtensa_semihosting.c > new file mode 100644 > index 000000000000..1bf3c18537e7 > --- /dev/null > +++ b/drivers/serial/serial_xtensa_semihosting.c > @@ -0,0 +1,79 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Copyright (C) 2024 Jiaxun Yang <[email protected]> > + */ > + > +#include <dm.h> > +#include <malloc.h> > +#include <serial.h> > + > +#include <asm/platform/simcall.h> > + > +/** > + * struct simc_serial_priv - Semihosting serial private data > + * @counter: Counter used to fake pending every other call > + */ > +struct simc_serial_priv { > + unsigned int counter; > +}; > + > +static int simc_serial_getc(struct udevice *dev) > +{ > + char ch = 0; > + > + simc_read(0, &ch, sizeof(ch)); > + > + return ch; > +} > + > +static int simc_serial_putc(struct udevice *dev, const char ch) > +{ > + char str[2] = {0}; Why does it need to be an array if only the first element is ever used? > + > + str[0] = ch; > + simc_write(1, str, 1); > + > + return 0; > +} > + > +static int simc_serial_pending(struct udevice *dev, bool input) > +{ > + struct simc_serial_priv *priv = dev_get_priv(dev); > + > + if (input) > + return priv->counter++ & 1; This can result in blocking the whole CPU thread of the emulator when used with simcall-based semihosting and there's no input actually available. Not sure how it would behave with the gdbio. I think something like the following: if (input) { int res = simc_poll(0); return res < 0 ? priv->counter++ & 1 : res; } could be used here to avoid that. > + return false; > +} > + > +static const struct dm_serial_ops simc_serial_ops = { > + .putc = simc_serial_putc, > + .getc = simc_serial_getc, > + .pending = simc_serial_pending, > +}; > + > +U_BOOT_DRIVER(simc_serial) = { > + .name = "serial_xtensa_semihosting", > + .id = UCLASS_SERIAL, > + .priv_auto = sizeof(struct simc_serial_priv), > + .ops = &simc_serial_ops, > + .flags = DM_FLAG_PRE_RELOC, > +}; > + > +U_BOOT_DRVINFO(simc_serial) = { > + .name = "serial_xtensa_semihosting", > +}; > + > +#if CONFIG_IS_ENABLED(DEBUG_UART_XTENSA_SEMIHOSTING) > +#include <debug_uart.h> > + > +static inline void _debug_uart_init(void) > +{ > +} > + > +static inline void _debug_uart_putc(int c) > +{ > + simc_serial_putc(NULL, c); > +} > + > +DEBUG_UART_FUNCS > +#endif > > -- > 2.43.0 > -- Thanks. -- Max
