On 11/30/2015 05:52 PM, Rob Herring wrote:

On Mon, Nov 30, 2015 at 10:21 AM, Paul Burton [off-list ref] wrote:

quoted

Read the reg-io-width property when earlycon is setup via device tree,
and set the I/O type to UPIO_MEM32 when 4 is read. This behaviour
matches that of the of_serial driver, and is needed for DT configured
earlycon on the MIPS Boston board.

Note that this is only possible when CONFIG_LIBFDT is enabled, but
enabling it everywhere seems like overkill. Thus systems that need this
functionality should select CONFIG_LIBFDT for themselves.

libfdt is enabled if you are booting from DT, so checking this
property should not add anything.

quoted

Signed-off-by: Paul Burton <redacted>
---

 drivers/of/fdt.c              |  2 +-
 drivers/tty/serial/Makefile   |  1 +
 drivers/tty/serial/earlycon.c | 15 ++++++++++++++-
 include/linux/serial_core.h   |  2 +-
 4 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index d243029..71c7f0d 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c

@@ -833,7 +833,7 @@ static int __init early_init_dt_scan_chosen_serial(void)
                if (addr == OF_BAD_ADDR)
                        return -ENXIO;

-               of_setup_earlycon(addr, match->data);
+               of_setup_earlycon(fdt, offset, addr, match->data);
                return 0;
        }
        return -ENODEV;

diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 5ab4111..1d290d6 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile

@@ -7,6 +7,7 @@ obj-$(CONFIG_SERIAL_21285) += 21285.o

 obj-$(CONFIG_SERIAL_EARLYCON) += earlycon.o
 obj-$(CONFIG_SERIAL_EARLYCON_ARM_SEMIHOST) += earlycon-arm-semihost.o
+CFLAGS_earlycon.o += -I$(srctree)/scripts/dtc/libfdt

This is no longer necessary.

quoted

 # These Sparc drivers have to appear before others such as 8250
 # which share ttySx minor node space.  Otherwise console device

diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
index f096360..2b936a7 100644
--- a/drivers/tty/serial/earlycon.c
+++ b/drivers/tty/serial/earlycon.c

@@ -17,6 +17,7 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/io.h>
+#include <linux/libfdt.h>
 #include <linux/serial_core.h>
 #include <linux/sizes.h>
 #include <linux/mod_devicetable.h>

@@ -196,17 +197,29 @@ static int __init param_setup_earlycon(char *buf)
 }
 early_param("earlycon", param_setup_earlycon);

-int __init of_setup_earlycon(unsigned long addr,
+int __init of_setup_earlycon(const void *fdt, int offset, unsigned long addr,

I would add iotype as a parameter instead, and then...

quoted

                             int (*setup)(struct earlycon_device *, const char *))
 {
        int err;
        struct uart_port *port = &early_console_dev.port;
+       const __be32 *prop;

        port->iotype = UPIO_MEM;
        port->mapbase = addr;
        port->uartclk = BASE_BAUD * 16;
        port->membase = earlycon_map(addr, SZ_4K);

+       if (config_enabled(CONFIG_LIBFDT)) {
+               prop = fdt_getprop(fdt, offset, "reg-io-width", NULL);
+               if (prop) {
+                       switch (be32_to_cpup(prop)) {
+                       case 4:
+                               port->iotype = UPIO_MEM32;
+                               break;
+                       }
+               }

...move this parsing into fdt.c where we parse the address.

FWIW, all of of_setup_earlycon() should only be #ifdef CONFIG_OF_EARLY_FLATTREE

Regards,
Peter Hurley