[PATCH 1/2] drivers/serial: Add driver for Aspeed virtual UART
Jeremy Kerr
jk at ozlabs.org
Fri Jan 29 15:55:47 AEDT 2016
This change adds a driver for the 16550-based Aspeed virtual UART
device. We use a similar process to the of_serial driver for device
probe, but expose some VUART-specific functions through sysfs too.
Signed-off-by: Jeremy Kerr <jk at ozlabs.org>
---
Documentation/devicetree/bindings/serial/8250.txt | 1 +
drivers/tty/serial/Kconfig | 10 +
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/aspeed-vuart.c | 313 ++++++++++++++++++++++
4 files changed, 325 insertions(+)
create mode 100644 drivers/tty/serial/aspeed-vuart.c
diff --git a/Documentation/devicetree/bindings/serial/8250.txt b/Documentation/devicetree/bindings/serial/8250.txt
index 91d5ab0..1b887f2 100644
--- a/Documentation/devicetree/bindings/serial/8250.txt
+++ b/Documentation/devicetree/bindings/serial/8250.txt
@@ -20,6 +20,7 @@ Required properties:
- "altr,16550-FIFO128"
- "fsl,16550-FIFO64"
- "fsl,ns16550"
+ - "aspeed,vuart"
- "serial" if the port type is unknown.
- reg : offset and length of the register set for the device.
- interrupts : should contain uart interrupt.
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 687b1ea..ffb59b4 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1093,6 +1093,16 @@ config SERIAL_NETX_CONSOLE
If you have enabled the serial port on the Hilscher NetX SoC
you can make it the console by answering Y to this option.
+config SERIAL_ASPEED_VUART
+ tristate "Aspeed Virtual UART"
+ depends on OF
+ depends on SERIAL_8250
+ help
+ If you want to use the virtual UART (VUART) device on Aspeed
+ BMC platforms, enable this option. This enables the 16550A-
+ compatible device on the local LPC bus, giving a UART device
+ with no physical RS232 connections.
+
config SERIAL_OF_PLATFORM
tristate "Serial port on Open Firmware platform bus"
depends on OF
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 5ab4111..72dc094 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_SERIAL_MSM) += msm_serial.o
obj-$(CONFIG_SERIAL_NETX) += netx-serial.o
obj-$(CONFIG_SERIAL_OF_PLATFORM) += of_serial.o
obj-$(CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL) += nwpserial.o
+obj-$(CONFIG_SERIAL_ASPEED_VUART) += aspeed-vuart.o
obj-$(CONFIG_SERIAL_KGDB_NMI) += kgdb_nmi.o
obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o
obj-$(CONFIG_SERIAL_OMAP) += omap-serial.o
diff --git a/drivers/tty/serial/aspeed-vuart.c b/drivers/tty/serial/aspeed-vuart.c
new file mode 100644
index 0000000..f1988dd
--- /dev/null
+++ b/drivers/tty/serial/aspeed-vuart.c
@@ -0,0 +1,313 @@
+/*
+ * Serial Port driver for Aspeed VUART device
+ *
+ * Copyright (C) 2016 Jeremy Kerr <jk at ozlabs.org>, IBM Corp.
+ * Copyright (C) 2006 Arnd Bergmann <arnd at 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 0x1
+#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_enabled(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_GCRA) & AST_VUART_GCRA_VUART_EN;
+
+ return snprintf(buf, PAGE_SIZE - 1, "%u\n", reg ? 1 : 0);
+}
+
+static ssize_t ast_vuart_set_enabled(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;
+
+ reg = readb(vuart->regs + AST_VUART_GCRA);
+ reg &= ~AST_VUART_GCRA_VUART_EN;
+ if (val)
+ reg |= AST_VUART_GCRA_VUART_EN;
+ writeb(reg, vuart->regs + AST_VUART_GCRA);
+
+ return count;
+}
+
+static DEVICE_ATTR(enabled, S_IWUSR | S_IRUGO,
+ ast_vuart_show_enabled, ast_vuart_set_enabled);
+
+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);
+
+/**
+ * The device tree parsinc 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.membase = vuart->regs;
+ port.port.mapbase = resource.start;
+ port.port.mapsize = resource_size(&resource);
+
+ 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;
+ 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");
+ rc = device_create_file(&pdev->dev, &dev_attr_enabled);
+ if (rc)
+ dev_warn(&pdev->dev, "can't create enabled 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);
+
+ 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 at ozlabs.org>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Driver for Aspeed VUART device");
--
2.5.0
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