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![Bin Meng](/assets/img/avatar_default.png)
When a driver declares DM_FLAG_PRE_RELOC flag, it wishes to be bound before relocation. However due to a bug in the DM core, the flag only takes effect when devices are statically declared via U_BOOT_DEVICE(). This bug has been fixed recently by commit "dm: core: Respect drivers with the DM_FLAG_PRE_RELOC flag in lists_bind_fdt()", but with the fix, it has a side effect that all existing drivers that declared DM_FLAG_PRE_RELOC flag will be bound before relocation now. This may expose potential boot failure on some boards due to insufficient memory during the pre-relocation stage. To mitigate this potential impact, the following changes are implemented: - Remove DM_FLAG_PRE_RELOC flag in the driver, if the driver only supports configuration from device tree (OF_CONTROL) - Keep DM_FLAG_PRE_RELOC flag in the driver only if the device is statically declared via U_BOOT_DEVICE() - Surround DM_FLAG_PRE_RELOC flag with OF_CONTROL check, for drivers that support both statically declared devices and configuration from device tree Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Simon Glass <sjg@chromium.org>
207 lines
4.7 KiB
C
207 lines
4.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* (C) Copyright 2016 Stephen Warren <swarren@wwwdotorg.org>
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*
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* Derived from pl01x code:
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*
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* (C) Copyright 2000
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* Rob Taylor, Flying Pig Systems. robt@flyingpig.com.
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*
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* (C) Copyright 2004
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* ARM Ltd.
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* Philippe Robin, <philippe.robin@arm.com>
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*/
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/* Simple U-Boot driver for the BCM283x mini UART */
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#include <common.h>
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#include <dm.h>
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#include <errno.h>
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#include <watchdog.h>
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#include <asm/gpio.h>
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#include <asm/io.h>
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#include <serial.h>
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#include <dm/platform_data/serial_bcm283x_mu.h>
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#include <dm/pinctrl.h>
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#include <linux/compiler.h>
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struct bcm283x_mu_regs {
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u32 io;
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u32 iir;
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u32 ier;
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u32 lcr;
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u32 mcr;
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u32 lsr;
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u32 msr;
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u32 scratch;
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u32 cntl;
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u32 stat;
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u32 baud;
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};
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#define BCM283X_MU_LCR_DATA_SIZE_8 3
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#define BCM283X_MU_LSR_TX_IDLE BIT(6)
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/* This actually means not full, but is named not empty in the docs */
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#define BCM283X_MU_LSR_TX_EMPTY BIT(5)
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#define BCM283X_MU_LSR_RX_READY BIT(0)
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struct bcm283x_mu_priv {
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struct bcm283x_mu_regs *regs;
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};
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static int bcm283x_mu_serial_getc(struct udevice *dev);
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static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate)
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{
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struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
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struct bcm283x_mu_priv *priv = dev_get_priv(dev);
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struct bcm283x_mu_regs *regs = priv->regs;
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u32 divider;
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if (plat->skip_init)
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goto out;
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divider = plat->clock / (baudrate * 8);
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writel(BCM283X_MU_LCR_DATA_SIZE_8, ®s->lcr);
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writel(divider - 1, ®s->baud);
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out:
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/* Flush the RX queue - all data in there is bogus */
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while (bcm283x_mu_serial_getc(dev) != -EAGAIN) ;
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return 0;
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}
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static int bcm283x_mu_serial_probe(struct udevice *dev)
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{
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struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
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struct bcm283x_mu_priv *priv = dev_get_priv(dev);
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priv->regs = (struct bcm283x_mu_regs *)plat->base;
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return 0;
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}
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static int bcm283x_mu_serial_getc(struct udevice *dev)
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{
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struct bcm283x_mu_priv *priv = dev_get_priv(dev);
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struct bcm283x_mu_regs *regs = priv->regs;
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u32 data;
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/* Wait until there is data in the FIFO */
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if (!(readl(®s->lsr) & BCM283X_MU_LSR_RX_READY))
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return -EAGAIN;
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data = readl(®s->io);
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return (int)data;
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}
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static int bcm283x_mu_serial_putc(struct udevice *dev, const char data)
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{
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struct bcm283x_mu_priv *priv = dev_get_priv(dev);
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struct bcm283x_mu_regs *regs = priv->regs;
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/* Wait until there is space in the FIFO */
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if (!(readl(®s->lsr) & BCM283X_MU_LSR_TX_EMPTY))
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return -EAGAIN;
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/* Send the character */
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writel(data, ®s->io);
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return 0;
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}
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static int bcm283x_mu_serial_pending(struct udevice *dev, bool input)
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{
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struct bcm283x_mu_priv *priv = dev_get_priv(dev);
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struct bcm283x_mu_regs *regs = priv->regs;
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unsigned int lsr;
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lsr = readl(®s->lsr);
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if (input) {
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WATCHDOG_RESET();
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return (lsr & BCM283X_MU_LSR_RX_READY) ? 1 : 0;
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} else {
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return (lsr & BCM283X_MU_LSR_TX_IDLE) ? 0 : 1;
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}
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}
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static const struct dm_serial_ops bcm283x_mu_serial_ops = {
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.putc = bcm283x_mu_serial_putc,
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.pending = bcm283x_mu_serial_pending,
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.getc = bcm283x_mu_serial_getc,
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.setbrg = bcm283x_mu_serial_setbrg,
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};
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#if CONFIG_IS_ENABLED(OF_CONTROL)
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static const struct udevice_id bcm283x_mu_serial_id[] = {
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{.compatible = "brcm,bcm2835-aux-uart"},
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{}
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};
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/*
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* Check if this serial device is muxed
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*
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* The serial device will only work properly if it has been muxed to the serial
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* pins by firmware. Check whether that happened here.
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*
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* @return true if serial device is muxed, false if not
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*/
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static bool bcm283x_is_serial_muxed(void)
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{
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int serial_gpio = 15;
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struct udevice *dev;
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if (uclass_first_device(UCLASS_PINCTRL, &dev) || !dev)
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return false;
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if (pinctrl_get_gpio_mux(dev, 0, serial_gpio) != BCM2835_GPIO_ALT5)
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return false;
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return true;
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}
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static int bcm283x_mu_serial_ofdata_to_platdata(struct udevice *dev)
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{
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struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
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fdt_addr_t addr;
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/* Don't spawn the device if it's not muxed */
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if (!bcm283x_is_serial_muxed())
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return -ENODEV;
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addr = devfdt_get_addr(dev);
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if (addr == FDT_ADDR_T_NONE)
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return -EINVAL;
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plat->base = addr;
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plat->clock = dev_read_u32_default(dev, "clock", 1);
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/*
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* TODO: Reinitialization doesn't always work for now, just skip
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* init always - we know we're already initialized
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*/
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plat->skip_init = true;
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return 0;
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}
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#endif
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U_BOOT_DRIVER(serial_bcm283x_mu) = {
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.name = "serial_bcm283x_mu",
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.id = UCLASS_SERIAL,
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.of_match = of_match_ptr(bcm283x_mu_serial_id),
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.ofdata_to_platdata = of_match_ptr(bcm283x_mu_serial_ofdata_to_platdata),
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.platdata_auto_alloc_size = sizeof(struct bcm283x_mu_serial_platdata),
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.probe = bcm283x_mu_serial_probe,
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.ops = &bcm283x_mu_serial_ops,
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#if !CONFIG_IS_ENABLED(OF_CONTROL)
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.flags = DM_FLAG_PRE_RELOC,
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#endif
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.priv_auto_alloc_size = sizeof(struct bcm283x_mu_priv),
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};
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