[PATCH v3] serial: pl011: honour serial aliases in device tree
From: Matthew Leach <hidden>
Date: 2012-08-28 15:41:28
Also in:
linux-arm-kernel, linux-serial
Subsystem:
arm primecell uart pl010 and pl011 drivers, the rest, tty layer and serial drivers · Maintainers:
Russell King, Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
If the order of UART nodes is changed in the device tree, then tty dev devices are attached to different serial ports causing the console to be directed to a different physical serial port. The "serial" aliases in the device tree should prevent this. This patch ensures that the UART driver creates tty devices that honour these aliases if a device tree is present. Acked-by: Linus Walleij <redacted> Reviewed-by: Will Deacon <redacted> Acked-by: Rob Herring <redacted> Signed-off-by: Matthew Leach <redacted> --- v3: minor consistency correction v2: use IS_ENABLED instead of ifdefs drivers/tty/serial/amba-pl011.c | 36 ++++++++++++++++++++++++++++++++++++ 1 files changed, 36 insertions(+), 0 deletions(-)
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index d3553b5..dc05dd1 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c@@ -52,6 +52,8 @@ #include <linux/scatterlist.h> #include <linux/delay.h> #include <linux/types.h> +#include <linux/of.h> +#include <linux/of_device.h> #include <linux/pinctrl/consumer.h> #include <linux/sizes.h>
@@ -1869,6 +1871,38 @@ static struct uart_driver amba_reg = { .cons = AMBA_CONSOLE, }; +static int pl011_probe_dt_alias(int index, struct device *dev) +{ + struct device_node *np; + static bool seen_dev_with_alias = false; + static bool seen_dev_without_alias = false; + int ret = index; + + if (!IS_ENABLED(CONFIG_OF)) + return ret; + + np = dev->of_node; + if (!np) + return ret; + + ret = of_alias_get_id(np, "serial"); + if (IS_ERR_VALUE(ret)) { + seen_dev_without_alias = true; + ret = index; + } else { + seen_dev_with_alias = true; + if (ret >= ARRAY_SIZE(amba_ports) || amba_ports[ret] != NULL) { + dev_warn(dev, "requested serial port %d not available.\n", ret); + ret = index; + } + } + + if (seen_dev_with_alias && seen_dev_without_alias) + dev_warn(dev, "aliased and non-aliased serial devices found in device tree. Serial port enumeration may be unpredictable.\n"); + + return ret; +} + static int pl011_probe(struct amba_device *dev, const struct amba_id *id) { struct uart_amba_port *uap;
@@ -1891,6 +1925,8 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id) goto out; } + i = pl011_probe_dt_alias(i, &dev->dev); + base = ioremap(dev->res.start, resource_size(&dev->res)); if (!base) { ret = -ENOMEM;
--
1.7.0.4