[PATCH 1/2] spi: apple: Add driver for Apple SPI controller
Mark Kettenis
mark.kettenis at xs4all.nl
Sat Jan 22 16:53:11 CET 2022
> From: Simon Glass <sjg at chromium.org>
> Date: Fri, 21 Jan 2022 18:40:25 -0700
Hi Simon,
> Hi Mark,
>
> On Sun, 16 Jan 2022 at 10:06, Mark Kettenis <kettenis at openbsd.org> wrote:
> >
> > Add a driver for the SPI controller integrated on Apple SoCs.
> > This is necessary to support the keyboard on Apple Silicon laopts
> > since their keyboard uses an Apple-specific HID over SPI protocol.
> >
> > Signed-off-by: Mark Kettenis <kettenis at openbsd.org>
> > ---
> > arch/arm/Kconfig | 2 +
> > drivers/spi/Kconfig | 7 +
> > drivers/spi/Makefile | 1 +
> > drivers/spi/apple_spi.c | 283 ++++++++++++++++++++++++++++++++++++++++
> > 4 files changed, 293 insertions(+)
> > create mode 100644 drivers/spi/apple_spi.c
>
> Reviewed-by: Simon Glass <sjg at chromium.org>
> Tested on: Macbook Air M1
> Tested-by: Simon Glass <sjg at chromium.org>
>
> with nits below
>
> Shouldn't you enable SPI flash and 'sspi' and 'sf' commands as well?
I don't feel comfortable doing that at this point. Nothing in U-Boot
needs to access the flash at the moment and those commands could
overwrite the system firmware and brick the machines (although we
suspect that the flash contents can be restored using a DFU restore).
> >
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index 04b4a20211..fed993a53d 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -937,6 +937,7 @@ config ARCH_APPLE
> > select DM_MAILBOX
> > select DM_RESET
> > select DM_SERIAL
> > + select DM_SPI
> > select DM_USB
> > select DM_VIDEO
> > select IOMMU
> > @@ -946,6 +947,7 @@ config ARCH_APPLE
> > select POSITION_INDEPENDENT
> > select POWER_DOMAIN
> > select REGMAP
> > + select SPI
> > select SYSCON
> > select SYSRESET
> > select SYSRESET_WATCHDOG
> > diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> > index d07e9a28af..0a6a85f9c4 100644
> > --- a/drivers/spi/Kconfig
> > +++ b/drivers/spi/Kconfig
> > @@ -50,6 +50,13 @@ config ALTERA_SPI
> > IP core. Please find details on the "Embedded Peripherals IP
> > User Guide" of Altera.
> >
> > +config APPLE_SPI
> > + bool "Apple SPI driver"
> > + default y if ARCH_APPLE
> > + help
> > + Enable the Apple SPI driver. This driver can be used to
> > + access the SPI flash and keyboard on machines based on Apple SoCs.
> > +
> > config ATCSPI200_SPI
> > bool "Andestech ATCSPI200 SPI driver"
> > help
> > diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> > index d2f24bccef..bea746f3e3 100644
> > --- a/drivers/spi/Makefile
> > +++ b/drivers/spi/Makefile
> > @@ -18,6 +18,7 @@ obj-$(CONFIG_SPI_MEM) += spi-mem-nodm.o
> > endif
> >
> > obj-$(CONFIG_ALTERA_SPI) += altera_spi.o
> > +obj-$(CONFIG_APPLE_SPI) += apple_spi.o
> > obj-$(CONFIG_ATH79_SPI) += ath79_spi.o
> > obj-$(CONFIG_ATMEL_QSPI) += atmel-quadspi.o
> > obj-$(CONFIG_ATMEL_SPI) += atmel_spi.o
> > diff --git a/drivers/spi/apple_spi.c b/drivers/spi/apple_spi.c
> > new file mode 100644
> > index 0000000000..3ae89dc638
> > --- /dev/null
> > +++ b/drivers/spi/apple_spi.c
> > @@ -0,0 +1,283 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (C) 2021 Mark Kettenis <kettenis at openbsd.org>
> > + * Copyright The Asahi Linux Contributors
> > + */
> > +
> > +#include <common.h>
> > +#include <dm.h>
> > +#include <clk.h>
> > +#include <spi.h>
> > +#include <asm/io.h>
> > +#include <linux/bitfield.h>
> > +#include <linux/delay.h>
> > +
> > +#define APPLE_SPI_CTRL 0x000
> > +#define APPLE_SPI_CTRL_RUN BIT(0)
> > +#define APPLE_SPI_CTRL_TX_RESET BIT(2)
> > +#define APPLE_SPI_CTRL_RX_RESET BIT(3)
> > +
> > +#define APPLE_SPI_CFG 0x004
> > +#define APPLE_SPI_CFG_CPHA BIT(1)
> > +#define APPLE_SPI_CFG_CPOL BIT(2)
> > +#define APPLE_SPI_CFG_MODE GENMASK(6, 5)
> > +#define APPLE_SPI_CFG_MODE_POLLED 0
> > +#define APPLE_SPI_CFG_MODE_IRQ 1
> > +#define APPLE_SPI_CFG_MODE_DMA 2
> > +#define APPLE_SPI_CFG_IE_RXCOMPLETE BIT(7)
> > +#define APPLE_SPI_CFG_IE_TXRXTHRESH BIT(8)
> > +#define APPLE_SPI_CFG_LSB_FIRST BIT(13)
> > +#define APPLE_SPI_CFG_WORD_SIZE GENMASK(16, 15)
> > +#define APPLE_SPI_CFG_WORD_SIZE_8B 0
> > +#define APPLE_SPI_CFG_WORD_SIZE_16B 1
> > +#define APPLE_SPI_CFG_WORD_SIZE_32B 2
> > +#define APPLE_SPI_CFG_FIFO_THRESH GENMASK(18, 17)
> > +#define APPLE_SPI_CFG_FIFO_THRESH_8B 0
> > +#define APPLE_SPI_CFG_FIFO_THRESH_4B 1
> > +#define APPLE_SPI_CFG_FIFO_THRESH_1B 2
> > +#define APPLE_SPI_CFG_IE_TXCOMPLETE BIT(21)
> > +
> > +#define APPLE_SPI_STATUS 0x008
> > +#define APPLE_SPI_STATUS_RXCOMPLETE BIT(0)
> > +#define APPLE_SPI_STATUS_TXRXTHRESH BIT(1)
> > +#define APPLE_SPI_STATUS_TXCOMPLETE BIT(2)
> > +
> > +#define APPLE_SPI_PIN 0x00c
> > +#define APPLE_SPI_PIN_KEEP_MOSI BIT(0)
> > +#define APPLE_SPI_PIN_CS BIT(1)
> > +
> > +#define APPLE_SPI_TXDATA 0x010
> > +#define APPLE_SPI_RXDATA 0x020
> > +#define APPLE_SPI_CLKDIV 0x030
> > +#define APPLE_SPI_CLKDIV_MIN 0x002
> > +#define APPLE_SPI_CLKDIV_MAX 0x7ff
> > +#define APPLE_SPI_RXCNT 0x034
> > +#define APPLE_SPI_WORD_DELAY 0x038
> > +#define APPLE_SPI_TXCNT 0x04c
> > +
> > +#define APPLE_SPI_FIFOSTAT 0x10c
> > +#define APPLE_SPI_FIFOSTAT_TXFULL BIT(4)
> > +#define APPLE_SPI_FIFOSTAT_LEVEL_TX GENMASK(15, 8)
> > +#define APPLE_SPI_FIFOSTAT_RXEMPTY BIT(20)
> > +#define APPLE_SPI_FIFOSTAT_LEVEL_RX GENMASK(31, 24)
> > +
> > +#define APPLE_SPI_IE_XFER 0x130
> > +#define APPLE_SPI_IF_XFER 0x134
> > +#define APPLE_SPI_XFER_RXCOMPLETE BIT(0)
> > +#define APPLE_SPI_XFER_TXCOMPLETE BIT(1)
> > +
> > +#define APPLE_SPI_IE_FIFO 0x138
> > +#define APPLE_SPI_IF_FIFO 0x13c
> > +#define APPLE_SPI_FIFO_RXTHRESH BIT(4)
> > +#define APPLE_SPI_FIFO_TXTHRESH BIT(5)
> > +#define APPLE_SPI_FIFO_RXFULL BIT(8)
> > +#define APPLE_SPI_FIFO_TXEMPTY BIT(9)
> > +#define APPLE_SPI_FIFO_RXUNDERRUN BIT(16)
> > +#define APPLE_SPI_FIFO_TXOVERFLOW BIT(17)
> > +
> > +#define APPLE_SPI_SHIFTCFG 0x150
> > +#define APPLE_SPI_SHIFTCFG_CLK_ENABLE BIT(0)
> > +#define APPLE_SPI_SHIFTCFG_CS_ENABLE BIT(1)
> > +#define APPLE_SPI_SHIFTCFG_AND_CLK_DATA BIT(8)
> > +#define APPLE_SPI_SHIFTCFG_CS_AS_DATA BIT(9)
> > +#define APPLE_SPI_SHIFTCFG_TX_ENABLE BIT(10)
> > +#define APPLE_SPI_SHIFTCFG_RX_ENABLE BIT(11)
> > +#define APPLE_SPI_SHIFTCFG_BITS GENMASK(21, 16)
> > +#define APPLE_SPI_SHIFTCFG_OVERRIDE_CS BIT(24)
> > +
> > +#define APPLE_SPI_PINCFG 0x154
> > +#define APPLE_SPI_PINCFG_KEEP_CLK BIT(0)
> > +#define APPLE_SPI_PINCFG_KEEP_CS BIT(1)
> > +#define APPLE_SPI_PINCFG_KEEP_MOSI BIT(2)
> > +#define APPLE_SPI_PINCFG_CLK_IDLE_VAL BIT(8)
> > +#define APPLE_SPI_PINCFG_CS_IDLE_VAL BIT(9)
> > +#define APPLE_SPI_PINCFG_MOSI_IDLE_VAL BIT(10)
> > +
> > +#define APPLE_SPI_DELAY_PRE 0x160
> > +#define APPLE_SPI_DELAY_POST 0x168
> > +#define APPLE_SPI_DELAY_ENABLE BIT(0)
> > +#define APPLE_SPI_DELAY_NO_INTERBYTE BIT(1)
> > +#define APPLE_SPI_DELAY_SET_SCK BIT(4)
> > +#define APPLE_SPI_DELAY_SET_MOSI BIT(6)
> > +#define APPLE_SPI_DELAY_SCK_VAL BIT(8)
> > +#define APPLE_SPI_DELAY_MOSI_VAL BIT(12)
> > +
> > +#define APPLE_SPI_FIFO_DEPTH 16
> > +
> > +#define APPLE_SPI_TIMEOUT_MS 200
> > +
> > +struct apple_spi_priv {
> > + void *base;
> > + u32 clkfreq;
>
> of the bus or the input peripheral (need scomment)
Sure; it's the input clock frequency.
>
> > +};
> > +
> > +static void apple_spi_set_cs(struct apple_spi_priv *priv, int on)
> > +{
> > + writel(on ? 0 : APPLE_SPI_PIN_CS, priv->base + APPLE_SPI_PIN);
> > +}
> > +
> > +static void apple_spi_tx(struct apple_spi_priv *priv, uint *len,
> > + const void **dout)
>
> needs comment
>
> > +{
> > + const u8 *out = *dout;
> > + u32 data, fifostat;
> > + uint count;
> > +
> > + fifostat = readl(priv->base + APPLE_SPI_FIFOSTAT);
> > + count = APPLE_SPI_FIFO_DEPTH -
> > + FIELD_GET(APPLE_SPI_FIFOSTAT_LEVEL_TX, fifostat);
> > + while (*len > 0 && count > 0) {
> > + data = out ? *out++ : 0;
> > + writel(data, priv->base + APPLE_SPI_TXDATA);
> > + (*len)--;
> > + count--;
> > + }
> > +
> > + *dout = out;
> > +}
> > +
> > +static void apple_spi_rx(struct apple_spi_priv *priv, uint *len,
> > + void **din)
>
> same
>
> > +{
> > + u8 *in = *din;
> > + u32 data, fifostat;
> > + uint count;
> > +
> > + fifostat = readl(priv->base + APPLE_SPI_FIFOSTAT);
> > + count = FIELD_GET(APPLE_SPI_FIFOSTAT_LEVEL_RX, fifostat);
> > + while (*len > 0 && count > 0) {
> > + data = readl(priv->base + APPLE_SPI_RXDATA);
> > + if (in)
> > + *in++ = data;
> > + (*len)--;
> > + count--;
> > + }
> > +
> > + *din = in;
> > +}
> > +
> > +static int apple_spi_xfer(struct udevice *dev, unsigned int bitlen,
> > + const void *dout, void *din, unsigned long flags)
> > +{
> > + struct apple_spi_priv *priv = dev_get_priv(dev->parent);
> > + unsigned long start = get_timer(0);
> > + uint txlen, rxlen;
> > + int ret = 0;
> > +
> > + if ((bitlen % 8) != 0)
>
> s/!= 0//
Hmm, really. It is a length so an explicit comparison to zero makes
more sense to me.
>
> > + return -EINVAL;
> > + txlen = rxlen = bitlen / 8;
> > +
> > + if (flags & SPI_XFER_BEGIN)
> > + apple_spi_set_cs(priv, 1);
> > +
> > + if (txlen > 0) {
>
> Can it be less than zero?
It is an unsigned variable, so no!
> > + /* Reset FIFOs */
> > + writel(APPLE_SPI_CTRL_RX_RESET | APPLE_SPI_CTRL_TX_RESET,
> > + priv->base + APPLE_SPI_CTRL);
> > +
> > + /* Set the transfer length */
> > + writel(txlen, priv->base + APPLE_SPI_TXCNT);
> > + writel(rxlen, priv->base + APPLE_SPI_RXCNT);
> > +
> > + /* Prime transmit FIFO */
> > + apple_spi_tx(priv, &txlen, &dout);
> > +
> > + /* Start transfer */
> > + writel(APPLE_SPI_CTRL_RUN, priv->base + APPLE_SPI_CTRL);
> > +
> > + while ((txlen > 0 || rxlen > 0)) {
>
> same question
same answer ;)
> > + apple_spi_rx(priv, &rxlen, &din);
> > + apple_spi_tx(priv, &txlen, &dout);
> > +
> > + if (get_timer(start) > APPLE_SPI_TIMEOUT_MS) {
> > + ret = -ETIMEDOUT;
> > + break;
> > + }
> > + }
> > +
> > + /* Stop transfer. */
> > + writel(0, priv->base + APPLE_SPI_CTRL);
> > + }
> > +
> > + if (flags & SPI_XFER_END)
> > + apple_spi_set_cs(priv, 0);
> > +
> > + return ret;
> > +}
> > +
> > +static int apple_spi_set_speed(struct udevice *dev, uint speed)
> > +{
> > + struct apple_spi_priv *priv = dev_get_priv(dev);
> > + u32 div;
> > +
> > + div = DIV_ROUND_UP(priv->clkfreq, speed);
> > + if (div < APPLE_SPI_CLKDIV_MIN)
> > + div = APPLE_SPI_CLKDIV_MIN;
> > + if (div > APPLE_SPI_CLKDIV_MAX)
> > + div = APPLE_SPI_CLKDIV_MAX;
> > +
> > + writel(div, priv->base + APPLE_SPI_CLKDIV);
> > +
> > + return 0;
> > +}
> > +
> > +static int apple_spi_set_mode(struct udevice *bus, uint mode)
> > +{
> > + return 0;
> > +}
> > +
> > +struct dm_spi_ops apple_spi_ops = {
> > + .xfer = apple_spi_xfer,
> > + .set_speed = apple_spi_set_speed,
> > + .set_mode = apple_spi_set_mode,
> > +};
> > +
> > +static int apple_spi_probe(struct udevice *dev)
> > +{
> > + struct apple_spi_priv *priv = dev_get_priv(dev);
> > + struct clk clkdev;
> > + int ret;
> > +
> > + priv->base = dev_read_addr_ptr(dev);
> > + if (!priv->base)
> > + return -EINVAL;
> > +
> > + ret = clk_get_by_index(dev, 0, &clkdev);
> > + if (ret)
> > + return ret;
> > + priv->clkfreq = clk_get_rate(&clkdev);
> > +
> > + /* Set CS high (inactive) and disable override and auto-CS */
> > + writel(APPLE_SPI_PIN_CS, priv->base + APPLE_SPI_PIN);
> > + writel(readl(priv->base + APPLE_SPI_SHIFTCFG) & ~APPLE_SPI_SHIFTCFG_OVERRIDE_CS,
> > + priv->base + APPLE_SPI_SHIFTCFG);
> > + writel((readl(priv->base + APPLE_SPI_PINCFG) & ~APPLE_SPI_PINCFG_CS_IDLE_VAL) |
> > + APPLE_SPI_PINCFG_KEEP_CS, priv->base + APPLE_SPI_PINCFG);
> > +
> > + /* Reset FIFOs */
> > + writel(APPLE_SPI_CTRL_RX_RESET | APPLE_SPI_CTRL_TX_RESET,
> > + priv->base + APPLE_SPI_CTRL);
> > +
> > + /* Configure defaults */
> > + writel(FIELD_PREP(APPLE_SPI_CFG_MODE, APPLE_SPI_CFG_MODE_IRQ) |
> > + FIELD_PREP(APPLE_SPI_CFG_WORD_SIZE, APPLE_SPI_CFG_WORD_SIZE_8B) |
> > + FIELD_PREP(APPLE_SPI_CFG_FIFO_THRESH, APPLE_SPI_CFG_FIFO_THRESH_8B),
> > + priv->base + APPLE_SPI_CFG);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct udevice_id apple_spi_of_match[] = {
> > + { .compatible = "apple,spi" },
> > + { /* sentinel */ }
> > +};
> > +
> > +U_BOOT_DRIVER(apple_spi) = {
> > + .name = "apple_spi",
> > + .id = UCLASS_SPI,
> > + .of_match = apple_spi_of_match,
> > + .probe = apple_spi_probe,
> > + .priv_auto = sizeof(struct apple_spi_priv),
> > + .ops = &apple_spi_ops,
> > +};
> > --
> > 2.34.1
> >
>
> Regards,
> Simon
>
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