/* * Serial Port driver for Aspeed VUART device * * Copyright (C) 2016 Jeremy Kerr , IBM Corp. * Copyright (C) 2006 Arnd Bergmann , IBM Corp. * * 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. * */ #include #include #include #include #include #include #include "8250/8250.h" #define AST_VUART_GCRA 0x20 #define AST_VUART_GCRA_VUART_EN 0x01 #define AST_VUART_GCRA_HOST_TX_DISCARD 0x20 #define AST_VUART_GCRB 0x24 #define AST_VUART_GCRB_HOST_SIRQ_MASK 0xf0 #define AST_VUART_GCRB_HOST_SIRQ_SHIFT 4 #define AST_VUART_ADDRL 0x28 #define AST_VUART_ADDRH 0x2c struct ast_vuart { struct platform_device *pdev; void __iomem *regs; struct clk *clk; int line; }; static ssize_t ast_vuart_show_addr(struct device *dev, struct device_attribute *attr, char *buf) { struct ast_vuart *vuart = dev_get_drvdata(dev); u16 addr; addr = (readb(vuart->regs + AST_VUART_ADDRH) << 8) | (readb(vuart->regs + AST_VUART_ADDRL)); return snprintf(buf, PAGE_SIZE - 1, "0x%x\n", addr); } static ssize_t ast_vuart_set_addr(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct ast_vuart *vuart = dev_get_drvdata(dev); unsigned long val; int err; err = kstrtoul(buf, 0, &val); if (err) return err; writeb((val >> 8) & 0xff, vuart->regs + AST_VUART_ADDRH); writeb((val >> 0) & 0xff, vuart->regs + AST_VUART_ADDRL); return count; } static DEVICE_ATTR(lpc_address, S_IWUSR | S_IRUGO, ast_vuart_show_addr, ast_vuart_set_addr); static ssize_t ast_vuart_show_sirq(struct device *dev, struct device_attribute *attr, char *buf) { struct ast_vuart *vuart = dev_get_drvdata(dev); u8 reg; reg = readb(vuart->regs + AST_VUART_GCRB); reg &= AST_VUART_GCRB_HOST_SIRQ_MASK; reg >>= AST_VUART_GCRB_HOST_SIRQ_SHIFT; return snprintf(buf, PAGE_SIZE - 1, "%u\n", reg); } static ssize_t ast_vuart_set_sirq(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct ast_vuart *vuart = dev_get_drvdata(dev); unsigned long val; int err; u8 reg; err = kstrtoul(buf, 0, &val); if (err) return err; val <<= AST_VUART_GCRB_HOST_SIRQ_SHIFT; val &= AST_VUART_GCRB_HOST_SIRQ_MASK; reg = readb(vuart->regs + AST_VUART_GCRB); reg &= ~AST_VUART_GCRB_HOST_SIRQ_MASK; reg |= val; writeb(reg, vuart->regs + AST_VUART_GCRB); return count; } static DEVICE_ATTR(sirq, S_IWUSR | S_IRUGO, ast_vuart_show_sirq, ast_vuart_set_sirq); static void ast_vuart_set_enabled(struct ast_vuart *vuart, bool enabled) { u8 reg; reg = readb(vuart->regs + AST_VUART_GCRA); reg &= ~AST_VUART_GCRA_VUART_EN; if (enabled) reg |= AST_VUART_GCRA_VUART_EN; writeb(reg, vuart->regs + AST_VUART_GCRA); } static void ast_vuart_set_host_tx_discard(struct ast_vuart *vuart, bool discard) { u8 reg; reg = readb(vuart->regs + AST_VUART_GCRA); /* if the HOST_TX_DISCARD bit is set, discard is *disabled* */ reg &= ~AST_VUART_GCRA_HOST_TX_DISCARD; if (!discard) reg |= AST_VUART_GCRA_HOST_TX_DISCARD; writeb(reg, vuart->regs + AST_VUART_GCRA); } static int ast_vuart_startup(struct uart_port *uart_port) { struct uart_8250_port *uart_8250_port = up_to_u8250p(uart_port); struct ast_vuart *vuart = uart_8250_port->port.private_data; int rc; rc = serial8250_do_startup(uart_port); if (rc) return rc; ast_vuart_set_host_tx_discard(vuart, false); return 0; } static void ast_vuart_shutdown(struct uart_port *uart_port) { struct uart_8250_port *uart_8250_port = up_to_u8250p(uart_port); struct ast_vuart *vuart = uart_8250_port->port.private_data; ast_vuart_set_host_tx_discard(vuart, true); serial8250_do_shutdown(uart_port); } /** * The device tree parsing code here is heavily based on that of the of_serial * driver, but we have a few core differences, as we need to use our own * ioremapping for extra register support */ static int ast_vuart_probe(struct platform_device *pdev) { struct uart_8250_port port; struct resource resource; struct ast_vuart *vuart; struct device_node *np; u32 clk, prop; int rc; np = pdev->dev.of_node; vuart = devm_kzalloc(&pdev->dev, sizeof(*vuart), GFP_KERNEL); if (!vuart) return -ENOMEM; vuart->pdev = pdev; rc = of_address_to_resource(np, 0, &resource); if (rc) { dev_warn(&pdev->dev, "invalid address\n"); return rc; } /* create our own mapping for VUART-specific registers */ vuart->regs = devm_ioremap_resource(&pdev->dev, &resource); if (IS_ERR(vuart->regs)) { dev_warn(&pdev->dev, "failed to map registers\n"); return PTR_ERR(vuart->regs); } memset(&port, 0, sizeof(port)); port.port.private_data = vuart; port.port.membase = vuart->regs; port.port.mapbase = resource.start; port.port.mapsize = resource_size(&resource); port.port.startup = ast_vuart_startup; port.port.shutdown = ast_vuart_shutdown; if (of_property_read_u32(np, "clock-frequency", &clk)) { vuart->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(vuart->clk)) { dev_warn(&pdev->dev, "clk or clock-frequency not defined\n"); return PTR_ERR(vuart->clk); } rc = clk_prepare_enable(vuart->clk); if (rc < 0) return rc; clk = clk_get_rate(vuart->clk); } /* If current-speed was set, then try not to change it. */ if (of_property_read_u32(np, "current-speed", &prop) == 0) port.port.custom_divisor = clk / (16 * prop); /* Check for shifted address mapping */ if (of_property_read_u32(np, "reg-offset", &prop) == 0) port.port.mapbase += prop; /* Check for registers offset within the devices address range */ if (of_property_read_u32(np, "reg-shift", &prop) == 0) port.port.regshift = prop; /* Check for fifo size */ if (of_property_read_u32(np, "fifo-size", &prop) == 0) port.port.fifosize = prop; /* Check for a fixed line number */ rc = of_alias_get_id(np, "serial"); if (rc >= 0) port.port.line = rc; port.port.irq = irq_of_parse_and_map(np, 0); port.port.irqflags = IRQF_SHARED; port.port.iotype = UPIO_MEM; if (of_property_read_u32(np, "reg-io-width", &prop) == 0) { switch (prop) { case 1: port.port.iotype = UPIO_MEM; break; case 4: port.port.iotype = of_device_is_big_endian(np) ? UPIO_MEM32BE : UPIO_MEM32; break; default: dev_warn(&pdev->dev, "unsupported reg-io-width (%d)\n", prop); rc = -EINVAL; goto err_clk_disable; } } port.port.type = PORT_16550A; port.port.uartclk = clk; port.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_NO_THRE_TEST; if (of_find_property(np, "no-loopback-test", NULL)) port.port.flags |= UPF_SKIP_TEST; port.port.dev = &pdev->dev; if (port.port.fifosize) port.capabilities = UART_CAP_FIFO; if (of_property_read_bool(pdev->dev.of_node, "auto-flow-control")) port.capabilities |= UART_CAP_AFE; rc = serial8250_register_8250_port(&port); if (rc < 0) goto err_clk_disable; vuart->line = rc; ast_vuart_set_enabled(vuart, true); ast_vuart_set_host_tx_discard(vuart, true); platform_set_drvdata(pdev, vuart); /* extra sysfs control */ rc = device_create_file(&pdev->dev, &dev_attr_lpc_address); if (rc) dev_warn(&pdev->dev, "can't create lpc_address file\n"); rc = device_create_file(&pdev->dev, &dev_attr_sirq); if (rc) dev_warn(&pdev->dev, "can't create sirq file\n"); return 0; err_clk_disable: if (vuart->clk) clk_disable_unprepare(vuart->clk); irq_dispose_mapping(port.port.irq); return rc; } static int ast_vuart_remove(struct platform_device *pdev) { struct ast_vuart *vuart = platform_get_drvdata(pdev); ast_vuart_set_enabled(vuart, false); if (vuart->clk) clk_disable_unprepare(vuart->clk); return 0; } static const struct of_device_id ast_vuart_table[] = { { .compatible = "aspeed,vuart" }, { }, }; static struct platform_driver ast_vuart_driver = { .driver = { .name = "aspeed-vuart", .of_match_table = ast_vuart_table, }, .probe = ast_vuart_probe, .remove = ast_vuart_remove, }; module_platform_driver(ast_vuart_driver); MODULE_AUTHOR("Jeremy Kerr "); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Driver for Aspeed VUART device");