From mboxrd@z Thu Jan 1 00:00:00 1970 From: matthew.leach@arm.com (Matthew Leach) Date: Wed, 22 Aug 2012 17:25:22 +0100 Subject: [PATCH v3] serial: pl011: honour serial aliases in device tree Message-ID: <1345652722-22668-1-git-send-email-matthew.leach@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 Reviewed-by: Will Deacon Acked-by: Rob Herring Signed-off-by: Matthew Leach --- 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 #include #include +#include +#include #include #include @@ -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