1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
|
// SPDX-License-Identifier: GPL-2.0+
/*
* T20 Motorola Atrix 4G and Droid X2 SPL stage configuration
*
* (C) Copyright 2025
* Svyatoslav Ryhel <clamor95@gmail.com>
*/
#include <asm/gpio.h>
#include <asm/arch/pinmux.h>
#include <asm/arch/tegra.h>
#include <asm/arch-tegra/pmc.h>
#include <spl_gpio.h>
#include <linux/delay.h>
/*
* Unlike all other supported Tegra devices and most known Tegra devices, the
* both Atrix 4G and Droid X2 have no hardware way to enter APX/RCM mode, which
* may lead to a dangerous situation when, if BCT is set correctly and the
* bootloader is faulty, the device will hang in a permanent brick state.
* Exiting from this state can be done only by disassembling the device and
* shortening testpad to the ground.
*
* To prevent this or to minimize the probability of such an accident, it was
* proposed to add the RCM rebooting hook as early into SPL as possible since
* SPL is much more robust and has minimal changes that can break bootflow.
*
* gpio_early_init_uart() function was chosen as it is the earliest function
* exposed for setup by the device. Hook performs a check for volume up
* button state and triggers RCM if it is pressed.
*/
void gpio_early_init_uart(void)
{
int value;
/* Configure pinmux for PR0 */
pinmux_set_func(PMUX_PINGRP_KBCA, PMUX_FUNC_KBC);
pinmux_set_pullupdown(PMUX_PINGRP_KBCA, PMUX_PULL_UP);
pinmux_tristate_disable(PMUX_PINGRP_KBCA);
/* Configure pinmux for PQ0 */
pinmux_set_func(PMUX_PINGRP_KBCC, PMUX_FUNC_KBC);
pinmux_set_pullupdown(PMUX_PINGRP_KBCC, PMUX_PULL_UP);
pinmux_tristate_disable(PMUX_PINGRP_KBCC);
/* Hog column 0 (PQ0) low - active */
spl_gpio_output(NULL, TEGRA_GPIO(Q, 0), 0);
udelay(500);
spl_gpio_input(NULL, TEGRA_GPIO(R, 0));
value = spl_gpio_get_value(NULL, TEGRA_GPIO(R, 0));
/* Enter RCM if button is pressed */
if (!value) {
tegra_pmc_writel(2, PMC_SCRATCH0);
tegra_pmc_writel(PMC_CNTRL_MAIN_RST, PMC_CNTRL);
}
}
|
