On Tue, Mar 28, 2017 at 04:14:58PM +1030, Joel Stanley wrote: > From: Jeremy Kerr <jk@xxxxxxxxxx> > > 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. > > OpenPOWER host firmware doesn't like it when the host-side of the > VUART's FIFO is not drained. This driver only disables host TX discard > mode when the port is in use. We set the VUART enabled bit when we bind > to the device, and clear it on unbind. > > We don't want to do this on open/release, as the host may be using this > bit to configure serial output modes, which is independent of whether > the devices has been opened by BMC userspace. > > Signed-off-by: Jeremy Kerr <jk@xxxxxxxxxx> > Signed-off-by: Joel Stanley <joel@xxxxxxxxx> > --- > Documentation/devicetree/bindings/serial/8250.txt | 2 + > drivers/tty/serial/Kconfig | 10 + > drivers/tty/serial/Makefile | 1 + > drivers/tty/serial/aspeed-vuart.c | 335 ++++++++++++++++++++++ > 4 files changed, 348 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 f86bb06c39e9..a12e9277ac5d 100644 > --- a/Documentation/devicetree/bindings/serial/8250.txt > +++ b/Documentation/devicetree/bindings/serial/8250.txt > @@ -19,6 +19,8 @@ Required properties: > - "altr,16550-FIFO128" > - "fsl,16550-FIFO64" > - "fsl,ns16550" > + - "aspeed,ast2400-vuart" > + - "aspeed,ast2500-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 e9cf5b67f1b7..758b69a51078 100644 > --- a/drivers/tty/serial/Kconfig > +++ b/drivers/tty/serial/Kconfig > @@ -1129,6 +1129,16 @@ 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_OMAP > tristate "OMAP serial port support" > depends on ARCH_OMAP2PLUS > diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile > index 2d6288bc4554..5b97b0fa29e2 100644 > --- a/drivers/tty/serial/Makefile > +++ b/drivers/tty/serial/Makefile > @@ -22,6 +22,7 @@ obj-$(CONFIG_SERIAL_8250) += 8250/ > > obj-$(CONFIG_SERIAL_AMBA_PL010) += amba-pl010.o > obj-$(CONFIG_SERIAL_AMBA_PL011) += amba-pl011.o > +obj-$(CONFIG_SERIAL_ASPEED_VUART) += aspeed-vuart.o > obj-$(CONFIG_SERIAL_CLPS711X) += clps711x.o > obj-$(CONFIG_SERIAL_PXA_NON8250) += pxa.o > obj-$(CONFIG_SERIAL_PNX8XXX) += pnx8xxx_uart.o > diff --git a/drivers/tty/serial/aspeed-vuart.c b/drivers/tty/serial/aspeed-vuart.c > new file mode 100644 > index 000000000000..fc6fa6d243c8 > --- /dev/null > +++ b/drivers/tty/serial/aspeed-vuart.c > @@ -0,0 +1,335 @@ > +/* > + * Serial Port driver for Aspeed VUART device > + * > + * Copyright (C) 2016 Jeremy Kerr <jk@xxxxxxxxxx>, IBM Corp. > + * Copyright (C) 2006 Arnd Bergmann <arnd@xxxxxxxx>, 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, 0664, > + ast_vuart_show_addr, ast_vuart_set_addr); DEVICE_ATTR_RW()? And why random sysfs files for a uart? Where have you documented these? > + > +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, 0664, > + ast_vuart_show_sirq, ast_vuart_set_sirq); DEVICE_ATTR_RW(). > + > +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"); use an attribute group? You just raced userspace and lost :( thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html