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c9bf43dd9d
After the UART was initialized, we may still have bogus data in the
RX queue if it was enabled with incorrect pin muxing before.
So let's flush the RX queue whenever we initialize baud rates.
This fixes a regression with the dynamic pinmuxing code when enable_uart=1
is not set in config.txt on Raspberry Pis that use pl011 for serial.
Fixes: caf2233b28 ("bcm283x: Add pinctrl driver")
Reported-by: Göran Lundberg <goran@lundberg.email>
Reported-by: Peter Robinson <pbrobinson@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Tested-by: Tuomas Tynkkynen <tuomas@tuxera.com>
96 lines
2.3 KiB
C
96 lines
2.3 KiB
C
/*
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* Copyright (c) 2018 Alexander Graf <agraf@suse.de>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <dm.h>
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#include <asm/gpio.h>
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#include <dm/pinctrl.h>
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#include <dm/platform_data/serial_pl01x.h>
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#include <serial.h>
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#include "serial_pl01x_internal.h"
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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_ALT0)
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return false;
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return true;
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}
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static int bcm283x_pl011_serial_ofdata_to_platdata(struct udevice *dev)
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{
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struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
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int ret;
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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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ret = pl01x_serial_ofdata_to_platdata(dev);
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if (ret)
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return ret;
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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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static int bcm283x_pl011_serial_setbrg(struct udevice *dev, int baudrate)
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{
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int r;
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r = pl01x_serial_setbrg(dev, baudrate);
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/*
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* We may have been muxed to a bogus line before. Drain the RX
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* queue so we start at a clean slate.
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*/
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while (pl01x_serial_getc(dev) != -EAGAIN) ;
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return r;
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}
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static const struct dm_serial_ops bcm283x_pl011_serial_ops = {
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.putc = pl01x_serial_putc,
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.pending = pl01x_serial_pending,
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.getc = pl01x_serial_getc,
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.setbrg = bcm283x_pl011_serial_setbrg,
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};
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static const struct udevice_id bcm283x_pl011_serial_id[] = {
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{.compatible = "brcm,bcm2835-pl011", .data = TYPE_PL011},
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{}
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};
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U_BOOT_DRIVER(bcm283x_pl011_uart) = {
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.name = "bcm283x_pl011",
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.id = UCLASS_SERIAL,
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.of_match = of_match_ptr(bcm283x_pl011_serial_id),
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.ofdata_to_platdata = of_match_ptr(bcm283x_pl011_serial_ofdata_to_platdata),
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.platdata_auto_alloc_size = sizeof(struct pl01x_serial_platdata),
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.probe = pl01x_serial_probe,
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.ops = &bcm283x_pl011_serial_ops,
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.flags = DM_FLAG_PRE_RELOC,
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.priv_auto_alloc_size = sizeof(struct pl01x_priv),
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};
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