On Wed, 2015-11-25 at 10:46 -0800, Curt Brune wrote: > Currently for PowerPC systems using device tree, the legacy serial > ports are allocated in the order by which they are found in the device > tree structure. > > This can cause problems in cases where the device tree nodes are > sysnthesized by an external program (kexec for example), which may not > preserve the original order of the device tree nodes. This in turn > can result in the serial console changing from ttyS0 to ttyS1 > unexpectedly. > > This patch uses the 'cell-index' property (if present) to map UART > device tree nodes to legacy serial port number. The cell-index > property is widely used in all the Freescale .dts files for PowerPC. > > Signed-off-by: Curt Brune <curt@xxxxxxxxxxxxxxxxxxx> > --- > arch/powerpc/kernel/legacy_serial.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kernel/legacy_serial.c > b/arch/powerpc/kernel/legacy_serial.c > index 7b750c4..b717133 100644 > --- a/arch/powerpc/kernel/legacy_serial.c > +++ b/arch/powerpc/kernel/legacy_serial.c > @@ -164,6 +164,8 @@ static int __init add_legacy_soc_port(struct device_node > *np, > u64 addr; > const __be32 *addrp; > struct device_node *tsi = of_get_parent(np); > + int index = -1, len; > + u32 *indexp; > > /* We only support ports that have a clock frequency properly > * encoded in the device-tree. > @@ -188,14 +190,19 @@ static int __init add_legacy_soc_port(struct > device_node *np, > if (addr == OF_BAD_ADDR) > return -1; > > + /* Check if the ports have an ordering, defined by 'cell-index' */ > + if (((indexp = (u32*)of_get_property(np, "cell-index", &len)) != > NULL) && > + (len == sizeof(u32))) > + index = *indexp; const u32 * Or better, use of_read_number() or similar. -Scott -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
