[Xen-changelog] [xen master] dt-uart: support /chosen/stdout-path property.

[patchbot@xxxxxxx]

commit c69ec40e260d54f5e0915fd59c67330efb442437
Author:     Ian Campbell <ian.campbell@xxxxxxxxxx>
AuthorDate: Thu Jan 8 11:53:56 2015 +0000
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Mon Jan 12 16:05:15 2015 +0000

    dt-uart: support /chosen/stdout-path property.
    
    ePAPR v1.1 section 3.5 defines the /chosen/stdout-path property to
    refer to the device to be used for boot console output, so if no
    dtuart property is given try to use that instead. This will make Xen
    find a suitable console by default on DT platforms which include this
    property.
    
    As it happens the dtuart option has the exact same syntax as
    stdout-path, so we can just copy the value into that buffer if it is
    empty. If the string is too large for the buffer we truncate and warn
    but continue in the hopes that enough of the path survived (i.e. only
    the options part was dropped) to get something out.
    
    FWIW support for this was added to Linux in v3.19-rc1 (7914a7c5651a
    "of: support passing console options with stdout-path") and a fairly
    large number of the dts files shipped with Linux have already included
    a stdout-path property for quite a while now.
    
    Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    Reviewed-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
 xen/arch/arm/domain_build.c |    2 ++
 xen/drivers/char/dt-uart.c  |   22 ++++++++++++++++++++++
 2 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index de180d8..c33a73c 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -424,6 +424,7 @@ static int write_properties(struct domain *d, struct 
kernel_info *kinfo,
          *   bootargs (from module #1, above).
          * * remove bootargs,  xen,dom0-bootargs, xen,xen-bootargs,
          *   linux,initrd-start and linux,initrd-end.
+         * * remove stdout-path.
          * * remove bootargs, linux,uefi-system-table,
          *   linux,uefi-mmap-start, linux,uefi-mmap-size,
          *   linux,uefi-mmap-desc-size, and linux,uefi-mmap-desc-ver
@@ -434,6 +435,7 @@ static int write_properties(struct domain *d, struct 
kernel_info *kinfo,
             if ( dt_property_name_is_equal(prop, "xen,xen-bootargs") ||
                  dt_property_name_is_equal(prop, "linux,initrd-start") ||
                  dt_property_name_is_equal(prop, "linux,initrd-end") ||
+                 dt_property_name_is_equal(prop, "stdout-path") ||
                  dt_property_name_is_equal(prop, "linux,uefi-system-table") ||
                  dt_property_name_is_equal(prop, "linux,uefi-mmap-start") ||
                  dt_property_name_is_equal(prop, "linux,uefi-mmap-size") ||
diff --git a/xen/drivers/char/dt-uart.c b/xen/drivers/char/dt-uart.c
index 695fdaa..d599322 100644
--- a/xen/drivers/char/dt-uart.c
+++ b/xen/drivers/char/dt-uart.c
@@ -22,6 +22,7 @@
 #include <xen/console.h>
 #include <xen/device_tree.h>
 #include <xen/serial.h>
+#include <xen/errno.h>
 
 /*
  * Configure UART port with a string:
@@ -46,6 +47,27 @@ void __init dt_uart_init(void)
 
     if ( !strcmp(opt_dtuart, "") )
     {
+        const struct dt_device_node *chosen = dt_find_node_by_path("/chosen");
+
+        if ( chosen )
+        {
+            const char *stdout;
+
+            ret = dt_property_read_string(chosen, "stdout-path", &stdout);
+            if ( ret >= 0 )
+            {
+                printk("Taking dtuart configuration from 
/chosen/stdout-path\n");
+                if ( strlcpy(opt_dtuart, stdout, sizeof(opt_dtuart))
+                     >= sizeof(opt_dtuart) )
+                    printk("WARNING: /chosen/stdout-path too long, 
truncated\n");
+            }
+            else if ( ret != -EINVAL /* Not present */ )
+                printk("Failed to read /chosen/stdout-path (%d)\n", ret);
+        }
+    }
+
+    if ( !strcmp(opt_dtuart, "") )
+    {
         printk("No dtuart path configured\n");
         return;
     }
--
generated by git-patchbot for /home/xen/git/xen.git#master

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