On 08/21/2012 05:18 AM, Matthew Leach wrote:
> 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.
>
> Signed-off-by: Matthew Leach <matthew.leach@xxxxxxx>
One comment/question below, but otherwise:
Acked-by: Rob Herring <rob.herring@xxxxxxxxxxx>
> ---
> drivers/tty/serial/amba-pl011.c | 39 +++++++++++++++++++++++++++++++++++++++
> 1 files changed, 39 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
> index c17923e..5919599 100644
> --- a/drivers/tty/serial/amba-pl011.c
> +++ b/drivers/tty/serial/amba-pl011.c
> @@ -52,6 +52,7 @@
> #include <linux/scatterlist.h>
> #include <linux/delay.h>
> #include <linux/types.h>
> +#include <linux/of_device.h>
> #include <linux/pinctrl/consumer.h>
>
> #include <asm/io.h>
> @@ -1869,6 +1870,42 @@ static struct uart_driver amba_reg = {
> .cons = AMBA_CONSOLE,
> };
>
> +#ifdef CONFIG_OF
Now that we have IS_ENABLED, perhaps we want to put this inside the
function instead?
if (!IS_ENABLED(CONFIG_OF))
return index;
> +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;
> +
> + 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;
> +}
> +#else
> +static int pl011_probe_dt_alias(int index, struct device *dev)
> +{
> + return index;
> +}
> +#endif
> +
> static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
> {
> struct uart_amba_port *uap;
> @@ -1891,6 +1928,8 @@ 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;
>
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