diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-01-29 10:13:27 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-01-29 10:13:27 -0800 |
commit | ca9b5b6283984f67434cee810f3b08e19630226d (patch) | |
tree | fb2e2db2434920a857b7ce6dfbd789b6f279d412 /drivers/tty/serial/meson_uart.c | |
parent | aac96626713fe167c672f9a008be0f514aa3e237 (diff) | |
parent | 85f4c95172d606dd66f7ee1fa50c45a245535ffd (diff) |
Merge tag 'tty-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial driver updates from Greg KH:
"Here are the big set of tty and serial driver updates for 5.6-rc1
Included in here are:
- dummy_con cleanups (touches lots of arch code)
- sysrq logic cleanups (touches lots of serial drivers)
- samsung driver fixes (wasn't really being built)
- conmakeshash move to tty subdir out of scripts
- lots of small tty/serial driver updates
All of these have been in linux-next for a while with no reported
issues"
* tag 'tty-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (140 commits)
tty: n_hdlc: Use flexible-array member and struct_size() helper
tty: baudrate: SPARC supports few more baud rates
tty: baudrate: Synchronise baud_table[] and baud_bits[]
tty: serial: meson_uart: Add support for kernel debugger
serial: imx: fix a race condition in receive path
serial: 8250_bcm2835aux: Document struct bcm2835aux_data
serial: 8250_bcm2835aux: Use generic remapping code
serial: 8250_bcm2835aux: Allocate uart_8250_port on stack
serial: 8250_bcm2835aux: Suppress register_port error on -EPROBE_DEFER
serial: 8250_bcm2835aux: Suppress clk_get error on -EPROBE_DEFER
serial: 8250_bcm2835aux: Fix line mismatch on driver unbind
serial_core: Remove unused member in uart_port
vt: Correct comment documenting do_take_over_console()
vt: Delete comment referencing non-existent unbind_con_driver()
arch/xtensa/setup: Drop dummy_con initialization
arch/x86/setup: Drop dummy_con initialization
arch/unicore32/setup: Drop dummy_con initialization
arch/sparc/setup: Drop dummy_con initialization
arch/sh/setup: Drop dummy_con initialization
arch/s390/setup: Drop dummy_con initialization
...
Diffstat (limited to 'drivers/tty/serial/meson_uart.c')
-rw-r--r-- | drivers/tty/serial/meson_uart.c | 70 |
1 files changed, 66 insertions, 4 deletions
diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c index 164b18372c02..d2c08b760f83 100644 --- a/drivers/tty/serial/meson_uart.c +++ b/drivers/tty/serial/meson_uart.c @@ -5,15 +5,12 @@ * Copyright (C) 2014 Carlo Caione <carlo@caione.org> */ -#if defined(CONFIG_SERIAL_MESON_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) -#define SUPPORT_SYSRQ -#endif - #include <linux/clk.h> #include <linux/console.h> #include <linux/delay.h> #include <linux/init.h> #include <linux/io.h> +#include <linux/iopoll.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/of.h> @@ -76,6 +73,8 @@ #define AML_UART_PORT_OFFSET 6 #define AML_UART_DEV_NAME "ttyAML" +#define AML_UART_POLL_USEC 5 +#define AML_UART_TIMEOUT_USEC 10000 static struct uart_driver meson_uart_driver; @@ -427,6 +426,64 @@ static void meson_uart_config_port(struct uart_port *port, int flags) } } +#ifdef CONFIG_CONSOLE_POLL +/* + * Console polling routines for writing and reading from the uart while + * in an interrupt or debug context (i.e. kgdb). + */ + +static int meson_uart_poll_get_char(struct uart_port *port) +{ + u32 c; + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + + if (readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY) + c = NO_POLL_CHAR; + else + c = readl(port->membase + AML_UART_RFIFO); + + spin_unlock_irqrestore(&port->lock, flags); + + return c; +} + +static void meson_uart_poll_put_char(struct uart_port *port, unsigned char c) +{ + unsigned long flags; + u32 reg; + int ret; + + spin_lock_irqsave(&port->lock, flags); + + /* Wait until FIFO is empty or timeout */ + ret = readl_poll_timeout_atomic(port->membase + AML_UART_STATUS, reg, + reg & AML_UART_TX_EMPTY, + AML_UART_POLL_USEC, + AML_UART_TIMEOUT_USEC); + if (ret == -ETIMEDOUT) { + dev_err(port->dev, "Timeout waiting for UART TX EMPTY\n"); + goto out; + } + + /* Write the character */ + writel(c, port->membase + AML_UART_WFIFO); + + /* Wait until FIFO is empty or timeout */ + ret = readl_poll_timeout_atomic(port->membase + AML_UART_STATUS, reg, + reg & AML_UART_TX_EMPTY, + AML_UART_POLL_USEC, + AML_UART_TIMEOUT_USEC); + if (ret == -ETIMEDOUT) + dev_err(port->dev, "Timeout waiting for UART TX EMPTY\n"); + +out: + spin_unlock_irqrestore(&port->lock, flags); +} + +#endif /* CONFIG_CONSOLE_POLL */ + static const struct uart_ops meson_uart_ops = { .set_mctrl = meson_uart_set_mctrl, .get_mctrl = meson_uart_get_mctrl, @@ -442,6 +499,10 @@ static const struct uart_ops meson_uart_ops = { .request_port = meson_uart_request_port, .release_port = meson_uart_release_port, .verify_port = meson_uart_verify_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = meson_uart_poll_get_char, + .poll_put_char = meson_uart_poll_put_char, +#endif }; #ifdef CONFIG_SERIAL_MESON_CONSOLE @@ -703,6 +764,7 @@ static int meson_uart_probe(struct platform_device *pdev) port->mapsize = resource_size(res_mem); port->irq = res_irq->start; port->flags = UPF_BOOT_AUTOCONF | UPF_LOW_LATENCY; + port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MESON_CONSOLE); port->dev = &pdev->dev; port->line = pdev->id; port->type = PORT_MESON; |