mirror of
https://github.com/AsahiLinux/u-boot
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966bfa7347
Enabling this driver requires some DT changes.
Adding DCC to root or main bus:
dcc: dcc {
compatible = "arm,dcc";
u-boot,dm-pre-reloc;
};
Extend alias list to link DCC:
serial0 = &uart0;
serial1 = &uart1;
serial2 = &dcc;
Change stdout-path to point to dcc port.
stdout-path = "serial2:115200n8";
Also add support for debug uart to help with early debug.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
176 lines
3.6 KiB
C
176 lines
3.6 KiB
C
/*
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* Copyright (C) 2004-2007 ARM Limited.
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* Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
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* Copyright (C) 2015 - 2016 Xilinx, Inc, Michal Simek
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*
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* SPDX-License-Identifier: GPL-2.0
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*
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* As a special exception, if other files instantiate templates or use macros
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* or inline functions from this file, or you compile this file and link it
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* with other works to produce a work based on this file, this file does not
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* by itself cause the resulting work to be covered by the GNU General Public
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* License. However the source code for this file must still be made available
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* in accordance with section (3) of the GNU General Public License.
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* This exception does not invalidate any other reasons why a work based on
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* this file might be covered by the GNU General Public License.
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*/
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#include <common.h>
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#include <dm.h>
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#include <serial.h>
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#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V7)
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/*
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* ARMV6 & ARMV7
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*/
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#define DCC_RBIT (1 << 30)
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#define DCC_WBIT (1 << 29)
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#define write_dcc(x) \
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__asm__ volatile ("mcr p14, 0, %0, c0, c5, 0\n" : : "r" (x))
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#define read_dcc(x) \
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__asm__ volatile ("mrc p14, 0, %0, c0, c5, 0\n" : "=r" (x))
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#define status_dcc(x) \
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__asm__ volatile ("mrc p14, 0, %0, c0, c1, 0\n" : "=r" (x))
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#elif defined(CONFIG_CPU_XSCALE)
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/*
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* XSCALE
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*/
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#define DCC_RBIT (1 << 31)
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#define DCC_WBIT (1 << 28)
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#define write_dcc(x) \
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__asm__ volatile ("mcr p14, 0, %0, c8, c0, 0\n" : : "r" (x))
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#define read_dcc(x) \
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__asm__ volatile ("mrc p14, 0, %0, c9, c0, 0\n" : "=r" (x))
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#define status_dcc(x) \
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__asm__ volatile ("mrc p14, 0, %0, c14, c0, 0\n" : "=r" (x))
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#elif defined(CONFIG_CPU_ARMV8)
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/*
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* ARMV8
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*/
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#define DCC_RBIT (1 << 30)
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#define DCC_WBIT (1 << 29)
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#define write_dcc(x) \
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__asm__ volatile ("msr dbgdtrtx_el0, %0\n" : : "r" (x))
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#define read_dcc(x) \
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__asm__ volatile ("mrs %0, dbgdtrrx_el0\n" : "=r" (x))
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#define status_dcc(x) \
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__asm__ volatile ("mrs %0, mdccsr_el0\n" : "=r" (x))
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#else
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#define DCC_RBIT (1 << 0)
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#define DCC_WBIT (1 << 1)
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#define write_dcc(x) \
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__asm__ volatile ("mcr p14, 0, %0, c1, c0, 0\n" : : "r" (x))
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#define read_dcc(x) \
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__asm__ volatile ("mrc p14, 0, %0, c1, c0, 0\n" : "=r" (x))
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#define status_dcc(x) \
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__asm__ volatile ("mrc p14, 0, %0, c0, c0, 0\n" : "=r" (x))
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#endif
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#define can_read_dcc(x) do { \
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status_dcc(x); \
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x &= DCC_RBIT; \
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} while (0);
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#define can_write_dcc(x) do { \
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status_dcc(x); \
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x &= DCC_WBIT; \
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x = (x == 0); \
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} while (0);
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#define TIMEOUT_COUNT 0x4000000
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static int arm_dcc_getc(struct udevice *dev)
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{
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int ch;
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register unsigned int reg;
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do {
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can_read_dcc(reg);
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} while (!reg);
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read_dcc(ch);
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return ch;
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}
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static int arm_dcc_putc(struct udevice *dev, char ch)
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{
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register unsigned int reg;
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unsigned int timeout_count = TIMEOUT_COUNT;
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while (--timeout_count) {
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can_write_dcc(reg);
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if (reg)
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break;
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}
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if (timeout_count == 0)
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return -EAGAIN;
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else
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write_dcc(ch);
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return 0;
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}
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static int arm_dcc_pending(struct udevice *dev, bool input)
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{
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register unsigned int reg;
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if (input) {
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can_read_dcc(reg);
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} else {
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can_write_dcc(reg);
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}
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return reg;
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}
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static const struct dm_serial_ops arm_dcc_ops = {
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.putc = arm_dcc_putc,
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.pending = arm_dcc_pending,
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.getc = arm_dcc_getc,
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};
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static const struct udevice_id arm_dcc_ids[] = {
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{ .compatible = "arm,dcc", },
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{ }
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};
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U_BOOT_DRIVER(serial_dcc) = {
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.name = "arm_dcc",
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.id = UCLASS_SERIAL,
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.of_match = arm_dcc_ids,
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.ops = &arm_dcc_ops,
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.flags = DM_FLAG_PRE_RELOC,
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};
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#ifdef CONFIG_DEBUG_UART_ARM_DCC
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#include <debug_uart.h>
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static inline void _debug_uart_init(void)
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{
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}
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static inline void _debug_uart_putc(int ch)
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{
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arm_dcc_putc(NULL, ch);
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}
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DEBUG_UART_FUNCS
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#endif
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