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![Alexander Graf](/assets/img/avatar_default.png)
On bcm2835 we need to ensure we only access serial devices that are muxed to the serial output pins of the pin header. To achieve this for the pl011 device, add a bcm2835 specific pl011 wrapper device that does this check but otherwise behaves like a pl011 device. Signed-off-by: Alexander Graf <agraf@suse.de>
74 lines
1.8 KiB
C
74 lines
1.8 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_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 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 = &pl01x_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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