1 files changed, 333 insertions, 0 deletions

diff --git a/drivers/tty/serial/aspeed-vuart.c b/drivers/tty/serial/aspeed-vuart.c
new file mode 100644
index 000000000000..020c8159d25d
--- /dev/null
+++ b/drivers/tty/serial/aspeed-vuart.c
@@ -0,0 +1,333 @@
+/*
+ *  Serial Port driver for Aspeed VUART device
+ *
+ *    Copyright (C) 2016 Jeremy Kerr <jk@ozlabs.org>, IBM Corp.
+ *    Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, 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 <linux/device.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/clk.h>
+
+#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.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;
+
+	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 <jk@ozlabs.org>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Driver for Aspeed VUART device");