136 lines
3.0 KiB
C
136 lines
3.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2025, Kuan-Wei Chiu <visitorckw@gmail.com>
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* Goldfish TTY driver for U-Boot
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*/
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#include <dm.h>
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#include <goldfish_tty.h>
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#include <mapmem.h>
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#include <serial.h>
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#include <asm/io.h>
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#include <linux/types.h>
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/* Goldfish TTY Register Offsets */
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#define GOLDFISH_TTY_PUT_CHAR 0x00
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#define GOLDFISH_TTY_BYTES_READY 0x04
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#define GOLDFISH_TTY_CMD 0x08
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#define GOLDFISH_TTY_DATA_PTR 0x10
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#define GOLDFISH_TTY_DATA_LEN 0x14
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#define GOLDFISH_TTY_DATA_PTR_HIGH 0x18
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#define GOLDFISH_TTY_VERSION 0x20
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/* Commands */
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#define CMD_WRITE_BUFFER 2
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#define CMD_READ_BUFFER 3
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struct goldfish_tty_priv {
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void __iomem *base;
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u8 rx_buf;
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};
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static int goldfish_serial_getc(struct udevice *dev)
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{
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struct goldfish_tty_priv *priv = dev_get_priv(dev);
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unsigned long paddr;
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u32 count;
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count = __raw_readl(priv->base + GOLDFISH_TTY_BYTES_READY);
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if (count == 0)
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return -EAGAIN;
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paddr = virt_to_phys((void *)&priv->rx_buf);
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__raw_writel(0, priv->base + GOLDFISH_TTY_DATA_PTR_HIGH);
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__raw_writel(paddr, priv->base + GOLDFISH_TTY_DATA_PTR);
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__raw_writel(1, priv->base + GOLDFISH_TTY_DATA_LEN);
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__raw_writel(CMD_READ_BUFFER, priv->base + GOLDFISH_TTY_CMD);
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return priv->rx_buf;
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}
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static int goldfish_serial_putc(struct udevice *dev, const char ch)
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{
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struct goldfish_tty_priv *priv = dev_get_priv(dev);
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__raw_writel(ch, priv->base + GOLDFISH_TTY_PUT_CHAR);
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return 0;
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}
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static int goldfish_serial_pending(struct udevice *dev, bool input)
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{
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struct goldfish_tty_priv *priv = dev_get_priv(dev);
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if (input)
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return __raw_readl(priv->base + GOLDFISH_TTY_BYTES_READY);
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return 0;
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}
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static int goldfish_serial_of_to_plat(struct udevice *dev)
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{
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struct goldfish_tty_plat *plat = dev_get_plat(dev);
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fdt_addr_t addr;
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addr = dev_read_addr(dev);
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if (addr != FDT_ADDR_T_NONE)
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plat->reg = addr;
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return 0;
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}
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static int goldfish_serial_probe(struct udevice *dev)
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{
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struct goldfish_tty_plat *plat = dev_get_plat(dev);
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struct goldfish_tty_priv *priv = dev_get_priv(dev);
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if (!plat->reg)
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return -EINVAL;
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priv->base = map_sysmem(plat->reg, 0x1000);
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return 0;
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}
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static const struct dm_serial_ops goldfish_serial_ops = {
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.putc = goldfish_serial_putc,
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.pending = goldfish_serial_pending,
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.getc = goldfish_serial_getc,
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};
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static const struct udevice_id goldfish_serial_ids[] = {
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{ .compatible = "google,goldfish-tty" },
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{ }
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};
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U_BOOT_DRIVER(serial_goldfish) = {
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.name = "serial_goldfish",
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.id = UCLASS_SERIAL,
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.of_match = goldfish_serial_ids,
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.of_to_plat = goldfish_serial_of_to_plat,
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.plat_auto = sizeof(struct goldfish_tty_plat),
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.probe = goldfish_serial_probe,
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.ops = &goldfish_serial_ops,
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.priv_auto = sizeof(struct goldfish_tty_priv),
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.flags = DM_FLAG_PRE_RELOC,
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};
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#ifdef CONFIG_DEBUG_UART_GOLDFISH
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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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void __iomem *base = (void __iomem *)CONFIG_VAL(DEBUG_UART_BASE);
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__raw_writel(ch, base + GOLDFISH_TTY_PUT_CHAR);
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}
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DEBUG_UART_FUNCS
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#endif
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