LXR linux/arch/mips/ralink/early

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *
   4 *  Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
   5 */
   6
   7#include <linux/io.h>
   8#include <linux/serial_reg.h>
   9
  10#include <asm/addrspace.h>
  11#include <asm/setup.h>
  12
  13#ifdef CONFIG_SOC_RT288X
  14#define EARLY_UART_BASE         0x300c00
  15#define CHIPID_BASE             0x300004
  16#elif defined(CONFIG_SOC_MT7621)
  17#define EARLY_UART_BASE         0x1E000c00
  18#define CHIPID_BASE             0x1E000004
  19#else
  20#define EARLY_UART_BASE         0x10000c00
  21#define CHIPID_BASE             0x10000004
  22#endif
  23
  24#define MT7628_CHIP_NAME1       0x20203832
  25
  26#define UART_REG_TX             0x04
  27#define UART_REG_LCR            0x0c
  28#define UART_REG_LSR            0x14
  29#define UART_REG_LSR_RT2880     0x1c
  30
  31static __iomem void *uart_membase = (__iomem void *) KSEG1ADDR(EARLY_UART_BASE);
  32static __iomem void *chipid_membase = (__iomem void *) KSEG1ADDR(CHIPID_BASE);
  33static int init_complete;
  34
  35static inline void uart_w32(u32 val, unsigned reg)
  36{
  37        __raw_writel(val, uart_membase + reg);
  38}
  39
  40static inline u32 uart_r32(unsigned reg)
  41{
  42        return __raw_readl(uart_membase + reg);
  43}
  44
  45static inline int soc_is_mt7628(void)
  46{
  47        return IS_ENABLED(CONFIG_SOC_MT7620) &&
  48                (__raw_readl(chipid_membase) == MT7628_CHIP_NAME1);
  49}
  50
  51static void find_uart_base(void)
  52{
  53        int i;
  54
  55        if (!soc_is_mt7628())
  56                return;
  57
  58        for (i = 0; i < 3; i++) {
  59                u32 reg = uart_r32(UART_REG_LCR + (0x100 * i));
  60
  61                if (!reg)
  62                        continue;
  63
  64                uart_membase = (__iomem void *) KSEG1ADDR(EARLY_UART_BASE +
  65                                                          (0x100 * i));
  66                break;
  67        }
  68}
  69
  70void prom_putchar(char ch)
  71{
  72        if (!init_complete) {
  73                find_uart_base();
  74                init_complete = 1;
  75        }
  76
  77        if (IS_ENABLED(CONFIG_SOC_MT7621) || soc_is_mt7628()) {
  78                uart_w32((unsigned char)ch, UART_TX);
  79                while ((uart_r32(UART_REG_LSR) & UART_LSR_THRE) == 0)
  80                        ;
  81        } else {
  82                while ((uart_r32(UART_REG_LSR_RT2880) & UART_LSR_THRE) == 0)
  83                        ;
  84                uart_w32((unsigned char)ch, UART_REG_TX);
  85                while ((uart_r32(UART_REG_LSR_RT2880) & UART_LSR_THRE) == 0)
  86                        ;
  87        }
  88}
  89