--- /dev/null
+/*
+ * 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.h"
+
+#define ASPEED_VUART_GCRA 0x20
+#define ASPEED_VUART_GCRA_VUART_EN BIT(0)
+#define ASPEED_VUART_GCRA_DISABLE_HOST_TX_DISCARD BIT(5)
+#define ASPEED_VUART_GCRB 0x24
+#define ASPEED_VUART_GCRB_HOST_SIRQ_MASK GENMASK(7, 4)
+#define ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT 4
+#define ASPEED_VUART_ADDRL 0x28
+#define ASPEED_VUART_ADDRH 0x2c
+
+struct aspeed_vuart {
+ struct device *dev;
+ void __iomem *regs;
+ struct clk *clk;
+ int line;
+};
+
+/*
+ * The VUART is basically two UART 'front ends' connected by their FIFO
+ * (no actual serial line in between). One is on the BMC side (management
+ * controller) and one is on the host CPU side.
+ *
+ * It allows the BMC to provide to the host a "UART" that pipes into
+ * the BMC itself and can then be turned by the BMC into a network console
+ * of some sort for example.
+ *
+ * This driver is for the BMC side. The sysfs files allow the BMC
+ * userspace which owns the system configuration policy, to specify
+ * at what IO port and interrupt number the host side will appear
+ * to the host on the Host <-> BMC LPC bus. It could be different on a
+ * different system (though most of them use 3f8/4).
+ */
+
+static ssize_t lpc_address_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct aspeed_vuart *vuart = dev_get_drvdata(dev);
+ u16 addr;
+
+ addr = (readb(vuart->regs + ASPEED_VUART_ADDRH) << 8) |
+ (readb(vuart->regs + ASPEED_VUART_ADDRL));
+
+ return snprintf(buf, PAGE_SIZE - 1, "0x%x\n", addr);
+}
+
+static ssize_t lpc_address_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct aspeed_vuart *vuart = dev_get_drvdata(dev);
+ unsigned long val;
+ int err;
+
+ err = kstrtoul(buf, 0, &val);
+ if (err)
+ return err;
+
+ writeb(val >> 8, vuart->regs + ASPEED_VUART_ADDRH);
+ writeb(val >> 0, vuart->regs + ASPEED_VUART_ADDRL);
+
+ return count;
+}
+
+static DEVICE_ATTR_RW(lpc_address);
+
+static ssize_t sirq_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct aspeed_vuart *vuart = dev_get_drvdata(dev);
+ u8 reg;
+
+ reg = readb(vuart->regs + ASPEED_VUART_GCRB);
+ reg &= ASPEED_VUART_GCRB_HOST_SIRQ_MASK;
+ reg >>= ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT;
+
+ return snprintf(buf, PAGE_SIZE - 1, "%u\n", reg);
+}
+
+static ssize_t sirq_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct aspeed_vuart *vuart = dev_get_drvdata(dev);
+ unsigned long val;
+ int err;
+ u8 reg;
+
+ err = kstrtoul(buf, 0, &val);
+ if (err)
+ return err;
+
+ val <<= ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT;
+ val &= ASPEED_VUART_GCRB_HOST_SIRQ_MASK;
+
+ reg = readb(vuart->regs + ASPEED_VUART_GCRB);
+ reg &= ~ASPEED_VUART_GCRB_HOST_SIRQ_MASK;
+ reg |= val;
+ writeb(reg, vuart->regs + ASPEED_VUART_GCRB);
+
+ return count;
+}
+
+static DEVICE_ATTR_RW(sirq);
+
+static struct attribute *aspeed_vuart_attrs[] = {
+ &dev_attr_sirq.attr,
+ &dev_attr_lpc_address.attr,
+ NULL,
+};
+
+static const struct attribute_group aspeed_vuart_attr_group = {
+ .attrs = aspeed_vuart_attrs,
+};
+
+static void aspeed_vuart_set_enabled(struct aspeed_vuart *vuart, bool enabled)
+{
+ u8 reg = readb(vuart->regs + ASPEED_VUART_GCRA);
+
+ if (enabled)
+ reg |= ASPEED_VUART_GCRA_VUART_EN;
+ else
+ reg &= ~ASPEED_VUART_GCRA_VUART_EN;
+
+ writeb(reg, vuart->regs + ASPEED_VUART_GCRA);
+}
+
+static void aspeed_vuart_set_host_tx_discard(struct aspeed_vuart *vuart,
+ bool discard)
+{
+ u8 reg;
+
+ reg = readb(vuart->regs + ASPEED_VUART_GCRA);
+
+ /* If the DISABLE_HOST_TX_DISCARD bit is set, discard is disabled */
+ if (!discard)
+ reg |= ASPEED_VUART_GCRA_DISABLE_HOST_TX_DISCARD;
+ else
+ reg &= ~ASPEED_VUART_GCRA_DISABLE_HOST_TX_DISCARD;
+
+ writeb(reg, vuart->regs + ASPEED_VUART_GCRA);
+}
+
+static int aspeed_vuart_startup(struct uart_port *uart_port)
+{
+ struct uart_8250_port *uart_8250_port = up_to_u8250p(uart_port);
+ struct aspeed_vuart *vuart = uart_8250_port->port.private_data;
+ int rc;
+
+ rc = serial8250_do_startup(uart_port);
+ if (rc)
+ return rc;
+
+ aspeed_vuart_set_host_tx_discard(vuart, false);
+
+ return 0;
+}
+
+static void aspeed_vuart_shutdown(struct uart_port *uart_port)
+{
+ struct uart_8250_port *uart_8250_port = up_to_u8250p(uart_port);
+ struct aspeed_vuart *vuart = uart_8250_port->port.private_data;
+
+ aspeed_vuart_set_host_tx_discard(vuart, true);
+
+ serial8250_do_shutdown(uart_port);
+}
+
+static int aspeed_vuart_probe(struct platform_device *pdev)
+{
+ struct uart_8250_port port;
+ struct aspeed_vuart *vuart;
+ struct device_node *np;
+ struct resource *res;
+ u32 clk, prop;
+ int rc;
+
+ np = pdev->dev.of_node;
+
+ vuart = devm_kzalloc(&pdev->dev, sizeof(*vuart), GFP_KERNEL);
+ if (!vuart)
+ return -ENOMEM;
+
+ vuart->dev = &pdev->dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ vuart->regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(vuart->regs))
+ return PTR_ERR(vuart->regs);
+
+ memset(&port, 0, sizeof(port));
+ port.port.private_data = vuart;
+ port.port.membase = vuart->regs;
+ port.port.mapbase = res->start;
+ port.port.mapsize = resource_size(res);
+ port.port.startup = aspeed_vuart_startup;
+ port.port.shutdown = aspeed_vuart_shutdown;
+ port.port.dev = &pdev->dev;
+
+ rc = sysfs_create_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);
+ if (rc < 0)
+ return rc;
+
+ 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;
+ 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_property_read_bool(np, "no-loopback-test"))
+ port.port.flags |= UPF_SKIP_TEST;
+
+ if (port.port.fifosize)
+ port.capabilities = UART_CAP_FIFO;
+
+ if (of_property_read_bool(np, "auto-flow-control"))
+ port.capabilities |= UART_CAP_AFE;
+
+ rc = serial8250_register_8250_port(&port);
+ if (rc < 0)
+ goto err_clk_disable;
+
+ vuart->line = rc;
+
+ aspeed_vuart_set_enabled(vuart, true);
+ aspeed_vuart_set_host_tx_discard(vuart, true);
+ platform_set_drvdata(pdev, vuart);
+
+ return 0;
+
+err_clk_disable:
+ clk_disable_unprepare(vuart->clk);
+ irq_dispose_mapping(port.port.irq);
+ return rc;
+}
+
+static int aspeed_vuart_remove(struct platform_device *pdev)
+{
+ struct aspeed_vuart *vuart = platform_get_drvdata(pdev);
+
+ aspeed_vuart_set_enabled(vuart, false);
+ serial8250_unregister_port(vuart->line);
+ sysfs_remove_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);
+ clk_disable_unprepare(vuart->clk);
+
+ return 0;
+}
+
+static const struct of_device_id aspeed_vuart_table[] = {
+ { .compatible = "aspeed,ast2400-vuart" },
+ { .compatible = "aspeed,ast2500-vuart" },
+ { },
+};
+
+static struct platform_driver aspeed_vuart_driver = {
+ .driver = {
+ .name = "aspeed-vuart",
+ .of_match_table = aspeed_vuart_table,
+ },
+ .probe = aspeed_vuart_probe,
+ .remove = aspeed_vuart_remove,
+};
+
+module_platform_driver(aspeed_vuart_driver);
+
+MODULE_AUTHOR("Jeremy Kerr <jk@ozlabs.org>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Driver for Aspeed VUART device");
projects / karo-tx-linux.git / commitdiff