| Message ID | 20170328054458.29341-3-joel@jms.id.au |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] serial: 8250: Add flag so drivers can avoid THRE probe | expand |
On Tue, Mar 28, 2017 at 04:14:58PM +1030, Joel Stanley wrote: > From: Jeremy Kerr <jk@ozlabs.org> > > 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@ozlabs.org> > Signed-off-by: Joel Stanley <joel@jms.id.au> > --- > 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@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, 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 linux-serial" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Mar 28, 2017 at 8:44 AM, Joel Stanley <joel@jms.id.au> wrote: > 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. > Documentation/devicetree/bindings/serial/8250.txt | 2 + > drivers/tty/serial/Kconfig | 10 + > drivers/tty/serial/Makefile | 1 + > drivers/tty/serial/aspeed-vuart.c | 335 ++++++++++++++++++++++ And why it's not under 8250 folder? > +#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 BIT(x) ? > +#define AST_VUART_GCRB 0x24 > +#define AST_VUART_GCRB_HOST_SIRQ_MASK 0xf0 GENMASK() ? > +#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; Ususally there is no need to keep pointer to sturct platform_device, rahter we need struct device *dev. > + 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)); It looks like you have register shift 2 bits and byte accessors. We have some helpers for that (serial_in() / serial_out() or alike). > + > + 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); Useless & 0xff. > + > + return count; > +} > +} > + > + Extra empty line. > +/** If you are going to use kernel doc do it in accordance with howto. > + * 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; And if np == NULL? > + > + 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); > + } Can you use platform_get-resource() + devm_ioremap_resource() ? If no, why? > + > + 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; Perhaps you need other way around, check for error and supply a default in such case. > + > + /* 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; This is set by core. You already supplied correct flag for that below. > + port.port.iotype = UPIO_MEM; > + if (of_property_read_u32(np, "reg-io-width", &prop) == 0) { You hide an error code from of_property_read_u32() here. Why? And if there is an error you are continuing with what? 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; You perhaps meant _read_bool() for sake of consistency. > + > + 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")) One line? > + 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; > +} -- With Best Regards, Andy Shevchenk -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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@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, 0664, + 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, 0664, + 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,ast2400-vuart" }, + { .compatible = "aspeed,ast2500-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");