| /* |
| * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| */ |
| |
| #include <linux/clk.h> |
| #include <linux/console.h> |
| #include <linux/io.h> |
| #include <linux/module.h> |
| #include <linux/of.h> |
| #include <linux/platform_device.h> |
| |
| #include "8250.h" |
| |
| /* Most (but not all) of UniPhier UART devices have 64-depth FIFO. */ |
| #define UNIPHIER_UART_DEFAULT_FIFO_SIZE 64 |
| |
| /* |
| * This hardware is similar to 8250, but its register map is a bit different: |
| * - MMIO32 (regshift = 2) |
| * - FCR is not at 2, but 3 |
| * - LCR and MCR are not at 3 and 4, they share 4 |
| * - Divisor latch at 9, no divisor latch access bit |
| */ |
| |
| #define UNIPHIER_UART_REGSHIFT 2 |
| |
| /* bit[15:8] = CHAR (not used), bit[7:0] = FCR */ |
| #define UNIPHIER_UART_CHAR_FCR (3 << (UNIPHIER_UART_REGSHIFT)) |
| /* bit[15:8] = LCR, bit[7:0] = MCR */ |
| #define UNIPHIER_UART_LCR_MCR (4 << (UNIPHIER_UART_REGSHIFT)) |
| /* Divisor Latch Register */ |
| #define UNIPHIER_UART_DLR (9 << (UNIPHIER_UART_REGSHIFT)) |
| |
| struct uniphier8250_priv { |
| int line; |
| struct clk *clk; |
| spinlock_t atomic_write_lock; |
| }; |
| |
| #ifdef CONFIG_SERIAL_8250_CONSOLE |
| static int __init uniphier_early_console_setup(struct earlycon_device *device, |
| const char *options) |
| { |
| if (!device->port.membase) |
| return -ENODEV; |
| |
| /* This hardware always expects MMIO32 register interface. */ |
| device->port.iotype = UPIO_MEM32; |
| device->port.regshift = UNIPHIER_UART_REGSHIFT; |
| |
| /* |
| * Do not touch the divisor register in early_serial8250_setup(); |
| * we assume it has been initialized by a boot loader. |
| */ |
| device->baud = 0; |
| |
| return early_serial8250_setup(device, options); |
| } |
| OF_EARLYCON_DECLARE(uniphier, "socionext,uniphier-uart", |
| uniphier_early_console_setup); |
| #endif |
| |
| /* |
| * The register map is slightly different from that of 8250. |
| * IO callbacks must be overridden for correct access to FCR, LCR, and MCR. |
| */ |
| static unsigned int uniphier_serial_in(struct uart_port *p, int offset) |
| { |
| unsigned int valshift = 0; |
| |
| switch (offset) { |
| case UART_LCR: |
| valshift = 8; |
| /* fall through */ |
| case UART_MCR: |
| offset = UNIPHIER_UART_LCR_MCR; |
| break; |
| default: |
| offset <<= UNIPHIER_UART_REGSHIFT; |
| break; |
| } |
| |
| /* |
| * The return value must be masked with 0xff because LCR and MCR reside |
| * in the same register that must be accessed by 32-bit write/read. |
| * 8 or 16 bit access to this hardware result in unexpected behavior. |
| */ |
| return (readl(p->membase + offset) >> valshift) & 0xff; |
| } |
| |
| static void uniphier_serial_out(struct uart_port *p, int offset, int value) |
| { |
| unsigned int valshift = 0; |
| bool normal = true; |
| |
| switch (offset) { |
| case UART_FCR: |
| offset = UNIPHIER_UART_CHAR_FCR; |
| break; |
| case UART_LCR: |
| valshift = 8; |
| /* Divisor latch access bit does not exist. */ |
| value &= ~UART_LCR_DLAB; |
| /* fall through */ |
| case UART_MCR: |
| offset = UNIPHIER_UART_LCR_MCR; |
| normal = false; |
| break; |
| default: |
| offset <<= UNIPHIER_UART_REGSHIFT; |
| break; |
| } |
| |
| if (normal) { |
| writel(value, p->membase + offset); |
| } else { |
| /* |
| * Special case: two registers share the same address that |
| * must be 32-bit accessed. As this is not longer atomic safe, |
| * take a lock just in case. |
| */ |
| struct uniphier8250_priv *priv = p->private_data; |
| unsigned long flags; |
| u32 tmp; |
| |
| spin_lock_irqsave(&priv->atomic_write_lock, flags); |
| tmp = readl(p->membase + offset); |
| tmp &= ~(0xff << valshift); |
| tmp |= value << valshift; |
| writel(tmp, p->membase + offset); |
| spin_unlock_irqrestore(&priv->atomic_write_lock, flags); |
| } |
| } |
| |
| /* |
| * This hardware does not have the divisor latch access bit. |
| * The divisor latch register exists at different address. |
| * Override dl_read/write callbacks. |
| */ |
| static int uniphier_serial_dl_read(struct uart_8250_port *up) |
| { |
| return readl(up->port.membase + UNIPHIER_UART_DLR); |
| } |
| |
| static void uniphier_serial_dl_write(struct uart_8250_port *up, int value) |
| { |
| writel(value, up->port.membase + UNIPHIER_UART_DLR); |
| } |
| |
| static int uniphier_of_serial_setup(struct device *dev, struct uart_port *port, |
| struct uniphier8250_priv *priv) |
| { |
| int ret; |
| u32 prop; |
| struct device_node *np = dev->of_node; |
| |
| ret = of_alias_get_id(np, "serial"); |
| if (ret < 0) { |
| dev_err(dev, "failed to get alias id\n"); |
| return ret; |
| } |
| port->line = priv->line = ret; |
| |
| /* Get clk rate through clk driver */ |
| priv->clk = devm_clk_get(dev, NULL); |
| if (IS_ERR(priv->clk)) { |
| dev_err(dev, "failed to get clock\n"); |
| return PTR_ERR(priv->clk); |
| } |
| |
| ret = clk_prepare_enable(priv->clk); |
| if (ret < 0) |
| return ret; |
| |
| port->uartclk = clk_get_rate(priv->clk); |
| |
| /* Check for fifo size */ |
| if (of_property_read_u32(np, "fifo-size", &prop) == 0) |
| port->fifosize = prop; |
| else |
| port->fifosize = UNIPHIER_UART_DEFAULT_FIFO_SIZE; |
| |
| return 0; |
| } |
| |
| static int uniphier_uart_probe(struct platform_device *pdev) |
| { |
| struct device *dev = &pdev->dev; |
| struct uart_8250_port up; |
| struct uniphier8250_priv *priv; |
| struct resource *regs; |
| void __iomem *membase; |
| int irq; |
| int ret; |
| |
| regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| if (!regs) { |
| dev_err(dev, "failed to get memory resource\n"); |
| return -EINVAL; |
| } |
| |
| membase = devm_ioremap(dev, regs->start, resource_size(regs)); |
| if (!membase) |
| return -ENOMEM; |
| |
| irq = platform_get_irq(pdev, 0); |
| if (irq < 0) { |
| dev_err(dev, "failed to get IRQ number\n"); |
| return irq; |
| } |
| |
| priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); |
| if (!priv) |
| return -ENOMEM; |
| |
| memset(&up, 0, sizeof(up)); |
| |
| ret = uniphier_of_serial_setup(dev, &up.port, priv); |
| if (ret < 0) |
| return ret; |
| |
| spin_lock_init(&priv->atomic_write_lock); |
| |
| up.port.dev = dev; |
| up.port.private_data = priv; |
| up.port.mapbase = regs->start; |
| up.port.mapsize = resource_size(regs); |
| up.port.membase = membase; |
| up.port.irq = irq; |
| |
| up.port.type = PORT_16550A; |
| up.port.iotype = UPIO_MEM32; |
| up.port.regshift = UNIPHIER_UART_REGSHIFT; |
| up.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE; |
| up.capabilities = UART_CAP_FIFO; |
| |
| up.port.serial_in = uniphier_serial_in; |
| up.port.serial_out = uniphier_serial_out; |
| up.dl_read = uniphier_serial_dl_read; |
| up.dl_write = uniphier_serial_dl_write; |
| |
| ret = serial8250_register_8250_port(&up); |
| if (ret < 0) { |
| dev_err(dev, "failed to register 8250 port\n"); |
| clk_disable_unprepare(priv->clk); |
| return ret; |
| } |
| |
| platform_set_drvdata(pdev, priv); |
| |
| return 0; |
| } |
| |
| static int uniphier_uart_remove(struct platform_device *pdev) |
| { |
| struct uniphier8250_priv *priv = platform_get_drvdata(pdev); |
| |
| serial8250_unregister_port(priv->line); |
| clk_disable_unprepare(priv->clk); |
| |
| return 0; |
| } |
| |
| static const struct of_device_id uniphier_uart_match[] = { |
| { .compatible = "socionext,uniphier-uart" }, |
| { /* sentinel */ } |
| }; |
| MODULE_DEVICE_TABLE(of, uniphier_uart_match); |
| |
| static struct platform_driver uniphier_uart_platform_driver = { |
| .probe = uniphier_uart_probe, |
| .remove = uniphier_uart_remove, |
| .driver = { |
| .name = "uniphier-uart", |
| .of_match_table = uniphier_uart_match, |
| }, |
| }; |
| module_platform_driver(uniphier_uart_platform_driver); |
| |
| MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>"); |
| MODULE_DESCRIPTION("UniPhier UART driver"); |
| MODULE_LICENSE("GPL"); |