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1// SPDX-License-Identifier: GPL-2.02/*3 * Renesas Emma Mobile 8250 driver4 *5 * Copyright (C) 2012 Magnus Damm6 */7 8#include <linux/device.h>9#include <linux/io.h>10#include <linux/module.h>11#include <linux/mod_devicetable.h>12#include <linux/serial_8250.h>13#include <linux/serial_reg.h>14#include <linux/platform_device.h>15#include <linux/clk.h>16 17#include "8250.h"18 19#define UART_DLL_EM 920#define UART_DLM_EM 1021#define UART_HCR0_EM 1122 23/*24 * A high value for UART_FCR_EM avoids overlapping with existing UART_*25 * register defines. UART_FCR_EM_HW is the real HW register offset.26 */27#define UART_FCR_EM 0x1000328#define UART_FCR_EM_HW 329 30#define UART_HCR0_EM_SW_RESET BIT(7) /* SW Reset */31 32struct serial8250_em_priv {33 int line;34};35 36static void serial8250_em_serial_out_helper(struct uart_port *p, int offset,37 int value)38{39 switch (offset) {40 case UART_TX: /* TX @ 0x00 */41 writeb(value, p->membase);42 break;43 case UART_LCR: /* LCR @ 0x10 (+1) */44 case UART_MCR: /* MCR @ 0x14 (+1) */45 case UART_SCR: /* SCR @ 0x20 (+1) */46 writel(value, p->membase + ((offset + 1) << 2));47 break;48 case UART_FCR_EM:49 writel(value, p->membase + (UART_FCR_EM_HW << 2));50 break;51 case UART_IER: /* IER @ 0x04 */52 value &= 0x0f; /* only 4 valid bits - not Xscale */53 fallthrough;54 case UART_DLL_EM: /* DLL @ 0x24 (+9) */55 case UART_DLM_EM: /* DLM @ 0x28 (+9) */56 case UART_HCR0_EM: /* HCR0 @ 0x2c */57 writel(value, p->membase + (offset << 2));58 break;59 }60}61 62static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset)63{64 switch (offset) {65 case UART_RX: /* RX @ 0x00 */66 return readb(p->membase);67 case UART_LCR: /* LCR @ 0x10 (+1) */68 case UART_MCR: /* MCR @ 0x14 (+1) */69 case UART_LSR: /* LSR @ 0x18 (+1) */70 case UART_MSR: /* MSR @ 0x1c (+1) */71 case UART_SCR: /* SCR @ 0x20 (+1) */72 return readl(p->membase + ((offset + 1) << 2));73 case UART_FCR_EM:74 return readl(p->membase + (UART_FCR_EM_HW << 2));75 case UART_IER: /* IER @ 0x04 */76 case UART_IIR: /* IIR @ 0x08 */77 case UART_DLL_EM: /* DLL @ 0x24 (+9) */78 case UART_DLM_EM: /* DLM @ 0x28 (+9) */79 case UART_HCR0_EM: /* HCR0 @ 0x2c */80 return readl(p->membase + (offset << 2));81 }82 return 0;83}84 85static void serial8250_em_reg_update(struct uart_port *p, int off, int value)86{87 unsigned int ier, fcr, lcr, mcr, hcr0;88 89 ier = serial8250_em_serial_in(p, UART_IER);90 fcr = serial8250_em_serial_in(p, UART_FCR_EM);91 lcr = serial8250_em_serial_in(p, UART_LCR);92 mcr = serial8250_em_serial_in(p, UART_MCR);93 hcr0 = serial8250_em_serial_in(p, UART_HCR0_EM);94 95 serial8250_em_serial_out_helper(p, UART_FCR_EM, fcr |96 UART_FCR_CLEAR_RCVR |97 UART_FCR_CLEAR_XMIT);98 serial8250_em_serial_out_helper(p, UART_HCR0_EM, hcr0 |99 UART_HCR0_EM_SW_RESET);100 serial8250_em_serial_out_helper(p, UART_HCR0_EM, hcr0 &101 ~UART_HCR0_EM_SW_RESET);102 103 switch (off) {104 case UART_FCR_EM:105 fcr = value;106 break;107 case UART_LCR:108 lcr = value;109 break;110 case UART_MCR:111 mcr = value;112 break;113 }114 115 serial8250_em_serial_out_helper(p, UART_IER, ier);116 serial8250_em_serial_out_helper(p, UART_FCR_EM, fcr);117 serial8250_em_serial_out_helper(p, UART_MCR, mcr);118 serial8250_em_serial_out_helper(p, UART_LCR, lcr);119 serial8250_em_serial_out_helper(p, UART_HCR0_EM, hcr0);120}121 122static void serial8250_em_serial_out(struct uart_port *p, int offset, int value)123{124 switch (offset) {125 case UART_TX:126 case UART_SCR:127 case UART_IER:128 case UART_DLL_EM:129 case UART_DLM_EM:130 serial8250_em_serial_out_helper(p, offset, value);131 break;132 case UART_FCR:133 serial8250_em_reg_update(p, UART_FCR_EM, value);134 break;135 case UART_LCR:136 case UART_MCR:137 serial8250_em_reg_update(p, offset, value);138 break;139 }140}141 142static u32 serial8250_em_serial_dl_read(struct uart_8250_port *up)143{144 return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8;145}146 147static void serial8250_em_serial_dl_write(struct uart_8250_port *up, u32 value)148{149 serial_out(up, UART_DLL_EM, value & 0xff);150 serial_out(up, UART_DLM_EM, value >> 8 & 0xff);151}152 153static int serial8250_em_probe(struct platform_device *pdev)154{155 struct serial8250_em_priv *priv;156 struct device *dev = &pdev->dev;157 struct uart_8250_port up;158 struct resource *regs;159 struct clk *sclk;160 int irq, ret;161 162 irq = platform_get_irq(pdev, 0);163 if (irq < 0)164 return irq;165 166 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);167 if (!regs)168 return dev_err_probe(dev, -EINVAL, "missing registers\n");169 170 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);171 if (!priv)172 return -ENOMEM;173 174 sclk = devm_clk_get_enabled(dev, "sclk");175 if (IS_ERR(sclk))176 return dev_err_probe(dev, PTR_ERR(sclk), "unable to get clock\n");177 178 memset(&up, 0, sizeof(up));179 up.port.mapbase = regs->start;180 up.port.irq = irq;181 up.port.type = PORT_16750;182 up.port.flags = UPF_FIXED_PORT | UPF_IOREMAP | UPF_FIXED_TYPE;183 up.port.dev = dev;184 up.port.private_data = priv;185 186 up.port.uartclk = clk_get_rate(sclk);187 188 up.port.iotype = UPIO_MEM32;189 up.port.serial_in = serial8250_em_serial_in;190 up.port.serial_out = serial8250_em_serial_out;191 up.dl_read = serial8250_em_serial_dl_read;192 up.dl_write = serial8250_em_serial_dl_write;193 194 ret = serial8250_register_8250_port(&up);195 if (ret < 0)196 return dev_err_probe(dev, ret, "unable to register 8250 port\n");197 198 priv->line = ret;199 platform_set_drvdata(pdev, priv);200 return 0;201}202 203static void serial8250_em_remove(struct platform_device *pdev)204{205 struct serial8250_em_priv *priv = platform_get_drvdata(pdev);206 207 serial8250_unregister_port(priv->line);208}209 210static const struct of_device_id serial8250_em_dt_ids[] = {211 { .compatible = "renesas,em-uart", },212 {},213};214MODULE_DEVICE_TABLE(of, serial8250_em_dt_ids);215 216static struct platform_driver serial8250_em_platform_driver = {217 .driver = {218 .name = "serial8250-em",219 .of_match_table = serial8250_em_dt_ids,220 },221 .probe = serial8250_em_probe,222 .remove_new = serial8250_em_remove,223};224 225module_platform_driver(serial8250_em_platform_driver);226 227MODULE_AUTHOR("Magnus Damm");228MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver");229MODULE_LICENSE("GPL v2");230