[PATCH 2/5] serial: s5p: Add Apple M1 support
Mark Kettenis
mark.kettenis at xs4all.nl
Sun Oct 3 00:15:46 CEST 2021
> From: Simon Glass <sjg at chromium.org>
> Date: Sun, 19 Sep 2021 21:15:59 -0600
>
> Hi Mark,
>
> On Sat, 18 Sept 2021 at 07:55, Mark Kettenis <kettenis at openbsd.org> wrote:
> >
> > Apple M1 SoCs include an S5L UART which is a variant of the S5P
> > UART. Add support for this variant and enable it by default
> > on Apple SoCs.
> >
> > Signed-off-by: Mark Kettenis <kettenis at openbsd.org>
> > ---
> > arch/arm/include/asm/arch-m1/clk.h | 11 ++++++++
> > arch/arm/include/asm/arch-m1/uart.h | 41 +++++++++++++++++++++++++++++
> > arch/arm/mach-apple/board.c | 5 ++++
> > drivers/serial/Kconfig | 2 +-
> > drivers/serial/serial_s5p.c | 22 ++++++++++++++++
> > 5 files changed, 80 insertions(+), 1 deletion(-)
> > create mode 100644 arch/arm/include/asm/arch-m1/clk.h
> > create mode 100644 arch/arm/include/asm/arch-m1/uart.h
> >
> > diff --git a/arch/arm/include/asm/arch-m1/clk.h b/arch/arm/include/asm/arch-m1/clk.h
> > new file mode 100644
> > index 0000000000..f4326d0c0f
> > --- /dev/null
> > +++ b/arch/arm/include/asm/arch-m1/clk.h
> > @@ -0,0 +1,11 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (C) 2021 Mark Kettenis <kettenis at openbsd.org>
> > + */
> > +
> > +#ifndef __ASM_ARM_ARCH_CLK_H_
> > +#define __ASM_ARM_ARCH_CLK_H_
> > +
> > +unsigned long get_uart_clk(int dev_index);
>
> comment? But this should be in a clock driver, unless you are trying
> to get a debug UART up ASAP with minimal code?
>
> > +
> > +#endif
> > diff --git a/arch/arm/include/asm/arch-m1/uart.h b/arch/arm/include/asm/arch-m1/uart.h
> > new file mode 100644
> > index 0000000000..d2a17a221e
> > --- /dev/null
> > +++ b/arch/arm/include/asm/arch-m1/uart.h
> > @@ -0,0 +1,41 @@
> > +/* SPDX-License-Identifier: GPL-2.0+ */
> > +/*
> > + * (C) Copyright 2009 Samsung Electronics
> > + * Minkyu Kang <mk7.kang at samsung.com>
> > + * Heungjun Kim <riverful.kim at samsung.com>
> > + */
> > +
> > +#ifndef __ASM_ARCH_UART_H_
> > +#define __ASM_ARCH_UART_H_
> > +
> > +#ifndef __ASSEMBLY__
> > +/* baudrate rest value */
> > +union br_rest {
> > + unsigned short slot; /* udivslot */
> > + unsigned char value; /* ufracval */
> > +};
> > +
> > +struct s5p_uart {
> > + unsigned int ulcon;
> > + unsigned int ucon;
> > + unsigned int ufcon;
> > + unsigned int umcon;
> > + unsigned int utrstat;
> > + unsigned int uerstat;
> > + unsigned int ufstat;
> > + unsigned int umstat;
> > + unsigned int utxh;
> > + unsigned int urxh;
> > + unsigned int ubrdiv;
> > + union br_rest rest;
> > + unsigned char res3[0x3fd0];
> > +};
> > +
> > +static inline int s5p_uart_divslot(void)
> > +{
> > + return 0;
> > +}
> > +
> > +#endif /* __ASSEMBLY__ */
> > +
> > +#endif
> > diff --git a/arch/arm/mach-apple/board.c b/arch/arm/mach-apple/board.c
> > index 0c8b35292e..8bc5c2f69e 100644
> > --- a/arch/arm/mach-apple/board.c
> > +++ b/arch/arm/mach-apple/board.c
> > @@ -156,3 +156,8 @@ ulong board_get_usable_ram_top(ulong total_size)
> > */
> > return 0x980000000;
> > }
> > +
> > +unsigned long get_uart_clk(int dev_index)
> > +{
> > + return 24000000;
>
> Should add to devicetree for the driver
>
> > +}
> > diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> > index 93348c0929..c3ac773929 100644
> > --- a/drivers/serial/Kconfig
> > +++ b/drivers/serial/Kconfig
> > @@ -719,7 +719,7 @@ config ROCKCHIP_SERIAL
> >
> > config S5P_SERIAL
> > bool "Support for Samsung S5P UART"
> > - depends on ARCH_EXYNOS || ARCH_S5PC1XX
> > + depends on ARCH_APPLE || ARCH_EXYNOS || ARCH_S5PC1XX
> > default y
> > help
> > Select this to enable Samsung S5P UART support.
> > diff --git a/drivers/serial/serial_s5p.c b/drivers/serial/serial_s5p.c
> > index 6d09952a5d..eb770d9b62 100644
> > --- a/drivers/serial/serial_s5p.c
> > +++ b/drivers/serial/serial_s5p.c
> > @@ -21,12 +21,21 @@
> >
> > DECLARE_GLOBAL_DATA_PTR;
> >
> > +#ifdef CONFIG_ARCH_APPLE
>
> This should use the compatible string to decide which variant it is,
> then the checks happen at runtime. We should never have arch-specific
> #ifdefs in drivers.
>
> > +#define RX_FIFO_COUNT_SHIFT 0
> > +#define RX_FIFO_COUNT_MASK (0xf << RX_FIFO_COUNT_SHIFT)
> > +#define RX_FIFO_FULL (1 << 8)
> > +#define TX_FIFO_COUNT_SHIFT 4
> > +#define TX_FIFO_COUNT_MASK (0xf << TX_FIFO_COUNT_SHIFT)
> > +#define TX_FIFO_FULL (1 << 9)
> > +#else
> > #define RX_FIFO_COUNT_SHIFT 0
> > #define RX_FIFO_COUNT_MASK (0xff << RX_FIFO_COUNT_SHIFT)
> > #define RX_FIFO_FULL (1 << 8)
> > #define TX_FIFO_COUNT_SHIFT 16
> > #define TX_FIFO_COUNT_MASK (0xff << TX_FIFO_COUNT_SHIFT)
> > #define TX_FIFO_FULL (1 << 24)
> > +#endif
> >
> > /* Information about a serial port */
> > struct s5p_serial_plat {
> > @@ -83,7 +92,11 @@ static void __maybe_unused s5p_serial_baud(struct s5p_uart *uart, uint uclk,
> > if (s5p_uart_divslot())
> > writew(udivslot[val % 16], &uart->rest.slot);
> > else
> > +#ifdef CONFIG_ARCH_APPLE
> > + writel(val % 16, &uart->rest.value);
> > +#else
> > writeb(val % 16, &uart->rest.value);
> > +#endif
> > }
> >
> > #ifndef CONFIG_SPL_BUILD
> > @@ -148,7 +161,11 @@ static int s5p_serial_getc(struct udevice *dev)
> > return -EAGAIN;
> >
> > serial_err_check(uart, 0);
> > +#ifdef CONFIG_ARCH_APPLE
> > + return (int)(readl(&uart->urxh) & 0xff);
> > +#else
> > return (int)(readb(&uart->urxh) & 0xff);
> > +#endif
> > }
> >
> > static int s5p_serial_putc(struct udevice *dev, const char ch)
> > @@ -159,7 +176,11 @@ static int s5p_serial_putc(struct udevice *dev, const char ch)
> > if (readl(&uart->ufstat) & TX_FIFO_FULL)
> > return -EAGAIN;
> >
> > +#ifdef CONFIG_ARCH_APPLE
> > + writel(ch, &uart->utxh);
> > +#else
> > writeb(ch, &uart->utxh);
> > +#endif
> > serial_err_check(uart, 1);
> >
> > return 0;
> > @@ -201,6 +222,7 @@ static const struct dm_serial_ops s5p_serial_ops = {
> >
> > static const struct udevice_id s5p_serial_ids[] = {
> > { .compatible = "samsung,exynos4210-uart" },
> > + { .compatible = "apple,s5l-uart" },
> > { }
> > };
> >
> > --
> > 2.33.0
> >
>
> Can you add debug UART support? Or does this already work?
I don't think it does work. But yes, I want to add it since it will
help a lot with debugging. That makes fixing some of the issues
raised by you and bing more problematic since the debug UART support
code:
- Needs to use 32-bit access on Apple M1, and using the "reg-io-width"
property there isn't possible.
- Relies on the FIFO control bits which are in a different position on
the Apple M1.
So I am starting to wonder whether it makes sense to simply copy
serial_s5p.c to serial_s5l.c and modify that one to do the right thing
on the apple SoC.
Alternatively I could introduce Kconfig stuff to switch between S5L
and S5P support.
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