On Wed, Nov 12, 2014 at 2:54 PM, Kevin Cernekee <cernekee@xxxxxxxxx> wrote:
> If an earlycon (stdout-path) node is being used, check for "big-endian"
> or "native-endian" properties and pass the appropriate iotype to the
> driver.
>
> Note that LE sets UPIO_MEM (8-bit) but BE sets UPIO_MEM32BE (32-bit). The
> big-endian property only really makes sense in the context of 32-bit
> registers, since 8-bit accesses never require data swapping.
>
> At some point, the of_earlycon code may want to pass in the reg-io-width,
> reg-offset, and reg-shift parameters too.
>
> Signed-off-by: Kevin Cernekee <cernekee@xxxxxxxxx>
> ---
> drivers/of/fdt.c | 9 ++++++++-
> drivers/tty/serial/earlycon.c | 4 ++--
> include/linux/serial_core.h | 2 +-
> 3 files changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 30e97bc..15f80c9 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -10,6 +10,7 @@
> */
>
> #include <linux/kernel.h>
> +#include <linux/kconfig.h>
> #include <linux/initrd.h>
> #include <linux/memblock.h>
> #include <linux/of.h>
> @@ -784,7 +785,13 @@ int __init early_init_dt_scan_chosen_serial(void)
> if (!addr)
> return -ENXIO;
>
> - of_setup_earlycon(addr, match->data);
> + if (fdt_getprop(fdt, offset, "big-endian", NULL) ||
> + (fdt_getprop(fdt, offset, "native-endian", NULL) &&
Is native-endian documented?
> + IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))) {
> + of_setup_earlycon(addr, UPIO_MEM32BE, match->data);
> + } else {
> + of_setup_earlycon(addr, UPIO_MEM, match->data);
> + }
I'd rather see something like this, so we can more easily add any
other properties later:
iotype = 0;
if (fdt_getprop(fdt, offset, "big-endian", NULL) ||
(fdt_getprop(fdt, offset, "native-endian", NULL) &&
IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)))
iotype = UPIO_MEM32BE;
of_setup_earlycon(addr, iotype ? : UPIO_MEM, match->data);
> return 0;
> }
> return -ENODEV;
> diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
> index a514ee6..548f7d7 100644
> --- a/drivers/tty/serial/earlycon.c
> +++ b/drivers/tty/serial/earlycon.c
> @@ -148,13 +148,13 @@ int __init setup_earlycon(char *buf, const char *match,
> return 0;
> }
>
> -int __init of_setup_earlycon(unsigned long addr,
> +int __init of_setup_earlycon(unsigned long addr, unsigned char iotype,
> int (*setup)(struct earlycon_device *, const char *))
> {
> int err;
> struct uart_port *port = &early_console_dev.port;
>
> - port->iotype = UPIO_MEM;
> + port->iotype = iotype;
> port->mapbase = addr;
> port->uartclk = BASE_BAUD * 16;
> port->membase = earlycon_map(addr, SZ_4K);
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> index d2d5bf6..0d60c64 100644
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -310,7 +310,7 @@ struct earlycon_device {
> int setup_earlycon(char *buf, const char *match,
> int (*setup)(struct earlycon_device *, const char *));
>
> -extern int of_setup_earlycon(unsigned long addr,
> +extern int of_setup_earlycon(unsigned long addr, unsigned char iotype,
> int (*setup)(struct earlycon_device *, const char *));
>
> #define EARLYCON_DECLARE(name, func) \
> --
> 2.1.1
>
