From: Graeme Gregory graeme.gregory@linaro.org
This is a subset of pl011 UART which does not supprt DMA or baud rate changing. It does, however, provide earlycon support (i.e., using "earlycon=ttySBSA" on the kernel command line).
It is specified in the Server Base System Architecture document from ARM.
Signed-off-by: Graeme Gregory graeme.gregory@linaro.org --- drivers/tty/Kconfig | 6 + drivers/tty/Makefile | 1 + drivers/tty/sbsauart.c | 355 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 362 insertions(+) create mode 100644 drivers/tty/sbsauart.c
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig index b24aa01..50fe279 100644 --- a/drivers/tty/Kconfig +++ b/drivers/tty/Kconfig @@ -419,4 +419,10 @@ config DA_CONSOLE help This enables a console on a Dash channel.
+config SBSAUART_TTY + tristate "SBSA UART TTY Driver" + help + Console and system TTY driver for the SBSA UART which is defined + in the Server Base System Architecure document for ARM64 servers. + endif # TTY diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile index 58ad1c0..c3211c0 100644 --- a/drivers/tty/Makefile +++ b/drivers/tty/Makefile @@ -29,5 +29,6 @@ obj-$(CONFIG_SYNCLINK) += synclink.o obj-$(CONFIG_PPC_EPAPR_HV_BYTECHAN) += ehv_bytechan.o obj-$(CONFIG_GOLDFISH_TTY) += goldfish.o obj-$(CONFIG_DA_TTY) += metag_da.o +obj-$(CONFIG_SBSAUART_TTY) += sbsauart.o
obj-y += ipwireless/ diff --git a/drivers/tty/sbsauart.c b/drivers/tty/sbsauart.c new file mode 100644 index 0000000..402f168 --- /dev/null +++ b/drivers/tty/sbsauart.c @@ -0,0 +1,355 @@ +/* + * SBSA (Server Base System Architecture) Compatible UART driver + * + * Copyright (C) 2014 Linaro Ltd + * + * Author: Graeme Gregory graeme.gregory@linaro.org + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/acpi.h> +#include <linux/amba/serial.h> +#include <linux/console.h> +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/serial_core.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> + +struct sbsa_tty { + struct tty_port port; + spinlock_t lock; + void __iomem *base; + u32 irq; + int opencount; + struct console console; +}; + +static struct tty_driver *sbsa_tty_driver; +static struct sbsa_tty *sbsa_tty; + +#define SBSAUART_CHAR_MASK 0xFF + +static void sbsa_raw_putc(struct uart_port *port, int c) +{ + while (readw(port->membase + UART01x_FR) & UART01x_FR_TXFF) + ; + writew(c & 0xFF, port->membase + UART01x_DR); +} + +static void sbsa_uart_early_write(struct console *con, const char *buf, + unsigned count) +{ + struct earlycon_device *dev = con->data; + + uart_console_write(&dev->port, buf, count, sbsa_raw_putc); +} + +static int __init sbsa_uart_early_console_setup(struct earlycon_device *device, + const char *opt) +{ + if (!device->port.membase) + return -ENODEV; + + device->con->write = sbsa_uart_early_write; + return 0; +} +EARLYCON_DECLARE(sbsauart, sbsa_uart_early_console_setup); + +static void sbsa_tty_do_write(const char *buf, unsigned count) +{ + unsigned long irq_flags; + struct sbsa_tty *qtty = sbsa_tty; + void __iomem *base = qtty->base; + unsigned n; + + spin_lock_irqsave(&qtty->lock, irq_flags); + for (n = 0; n < count; n++) { + while (readw(base + UART01x_FR) & UART01x_FR_TXFF) + ; + writew(buf[n], base + UART01x_DR); + } + spin_unlock_irqrestore(&qtty->lock, irq_flags); +} + +static void sbsauart_fifo_to_tty(struct sbsa_tty *qtty) +{ + void __iomem *base = qtty->base; + unsigned int flag, max_count = 32; + u16 status, ch; + + while (max_count--) { + status = readw(base + UART01x_FR); + if (status & UART01x_FR_RXFE) + break; + + /* Take chars from the FIFO and update status */ + ch = readw(base + UART01x_DR); + flag = TTY_NORMAL; + + if (ch & UART011_DR_BE) + flag = TTY_BREAK; + else if (ch & UART011_DR_PE) + flag = TTY_PARITY; + else if (ch & UART011_DR_FE) + flag = TTY_FRAME; + else if (ch & UART011_DR_OE) + flag = TTY_OVERRUN; + + ch &= SBSAUART_CHAR_MASK; + + tty_insert_flip_char(&qtty->port, ch, flag); + } + + tty_schedule_flip(&qtty->port); + + /* Clear the RX IRQ */ + writew(UART011_RXIC | UART011_RXIC, base + UART011_ICR); +} + +static irqreturn_t sbsa_tty_interrupt(int irq, void *dev_id) +{ + struct sbsa_tty *qtty = sbsa_tty; + unsigned long irq_flags; + + spin_lock_irqsave(&qtty->lock, irq_flags); + sbsauart_fifo_to_tty(qtty); + spin_unlock_irqrestore(&qtty->lock, irq_flags); + + return IRQ_HANDLED; +} + +static int sbsa_tty_open(struct tty_struct *tty, struct file *filp) +{ + struct sbsa_tty *qtty = sbsa_tty; + + return tty_port_open(&qtty->port, tty, filp); +} + +static void sbsa_tty_close(struct tty_struct *tty, struct file *filp) +{ + tty_port_close(tty->port, tty, filp); +} + +static void sbsa_tty_hangup(struct tty_struct *tty) +{ + tty_port_hangup(tty->port); +} + +static int sbsa_tty_write(struct tty_struct *tty, const unsigned char *buf, + int count) +{ + sbsa_tty_do_write(buf, count); + return count; +} + +static int sbsa_tty_write_room(struct tty_struct *tty) +{ + return 32; +} + +static void sbsa_tty_console_write(struct console *co, const char *b, + unsigned count) +{ + sbsa_tty_do_write(b, count); + + if (b[count - 1] == '\n') + sbsa_tty_do_write("\r", 1); +} + +static struct tty_driver *sbsa_tty_console_device(struct console *c, + int *index) +{ + *index = c->index; + return sbsa_tty_driver; +} + +static int sbsa_tty_console_setup(struct console *co, char *options) +{ + if ((unsigned)co->index > 0) + return -ENODEV; + if (sbsa_tty->base == NULL) + return -ENODEV; + return 0; +} + +static struct tty_port_operations sbsa_port_ops = { +}; + +static const struct tty_operations sbsa_tty_ops = { + .open = sbsa_tty_open, + .close = sbsa_tty_close, + .hangup = sbsa_tty_hangup, + .write = sbsa_tty_write, + .write_room = sbsa_tty_write_room, +}; + +static int sbsa_tty_create_driver(void) +{ + int ret; + struct tty_driver *tty; + + sbsa_tty = kzalloc(sizeof(*sbsa_tty), GFP_KERNEL); + if (sbsa_tty == NULL) { + ret = -ENOMEM; + goto err_alloc_sbsa_tty_failed; + } + tty = alloc_tty_driver(1); + if (tty == NULL) { + ret = -ENOMEM; + goto err_alloc_tty_driver_failed; + } + tty->driver_name = "sbsauart"; + tty->name = "ttySBSA"; + tty->type = TTY_DRIVER_TYPE_SERIAL; + tty->subtype = SERIAL_TYPE_NORMAL; + tty->init_termios = tty_std_termios; + tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | + TTY_DRIVER_DYNAMIC_DEV; + tty_set_operations(tty, &sbsa_tty_ops); + ret = tty_register_driver(tty); + if (ret) + goto err_tty_register_driver_failed; + + sbsa_tty_driver = tty; + return 0; + +err_tty_register_driver_failed: + put_tty_driver(tty); +err_alloc_tty_driver_failed: + kfree(sbsa_tty); + sbsa_tty = NULL; +err_alloc_sbsa_tty_failed: + return ret; +} + +static void sbsa_tty_delete_driver(void) +{ + tty_unregister_driver(sbsa_tty_driver); + put_tty_driver(sbsa_tty_driver); + sbsa_tty_driver = NULL; + kfree(sbsa_tty); + sbsa_tty = NULL; +} + +static int sbsa_tty_probe(struct platform_device *pdev) +{ + struct sbsa_tty *qtty; + int ret = -EINVAL; + int i; + struct resource *r; + struct device *ttydev; + void __iomem *base; + u32 irq; + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (r == NULL) + return -EINVAL; + + base = ioremap(r->start, r->end - r->start); + if (base == NULL) + pr_err("sbsa_tty: unable to remap base\n"); + + r = platform_get_resource(pdev, IORESOURCE_IRQ, 0); + if (r == NULL) + goto err_unmap; + + irq = r->start; + + if (pdev->id > 0) + goto err_unmap; + + ret = sbsa_tty_create_driver(); + if (ret) + goto err_unmap; + + qtty = sbsa_tty; + spin_lock_init(&qtty->lock); + tty_port_init(&qtty->port); + qtty->port.ops = &sbsa_port_ops; + qtty->base = base; + qtty->irq = irq; + + /* Clear and Mask all IRQs */ + writew(0, base + UART011_IMSC); + writew(0xFFFF, base + UART011_ICR); + + ret = request_irq(irq, sbsa_tty_interrupt, IRQF_SHARED, + "sbsa_tty", pdev); + if (ret) + goto err_request_irq_failed; + + /* Unmask the RX IRQ */ + writew(UART011_RXIM | UART011_RTIM, base + UART011_IMSC); + + ttydev = tty_port_register_device(&qtty->port, sbsa_tty_driver, + 0, &pdev->dev); + if (IS_ERR(ttydev)) { + ret = PTR_ERR(ttydev); + goto err_tty_register_device_failed; + } + + strcpy(qtty->console.name, "ttySBSA"); + qtty->console.write = sbsa_tty_console_write; + qtty->console.device = sbsa_tty_console_device; + qtty->console.setup = sbsa_tty_console_setup; + qtty->console.flags = CON_PRINTBUFFER; + qtty->console.index = pdev->id; + register_console(&qtty->console); + + return 0; + + tty_unregister_device(sbsa_tty_driver, i); +err_tty_register_device_failed: + free_irq(irq, pdev); +err_request_irq_failed: + sbsa_tty_delete_driver(); +err_unmap: + iounmap(base); + return ret; +} + +static int sbsa_tty_remove(struct platform_device *pdev) +{ + struct sbsa_tty *qtty; + + qtty = sbsa_tty; + unregister_console(&qtty->console); + tty_unregister_device(sbsa_tty_driver, pdev->id); + iounmap(qtty->base); + qtty->base = 0; + free_irq(qtty->irq, pdev); + sbsa_tty_delete_driver(); + return 0; +} + +static const struct acpi_device_id sbsa_acpi_match[] = { + { "ARMH0011", 0 }, + { } +}; + +static struct platform_driver sbsa_tty_platform_driver = { + .probe = sbsa_tty_probe, + .remove = sbsa_tty_remove, + .driver = { + .name = "sbsa_tty", + .acpi_match_table = ACPI_PTR(sbsa_acpi_match), + } +}; + +module_platform_driver(sbsa_tty_platform_driver); + +MODULE_LICENSE("GPL v2");