Hi Rob:
thanks for your review.
On 2016年01月21日 02:28, Rob Herring wrote:
On Tue, Jan 12, 2016 at 07:29:49PM +0800, Andy Yan wrote:
add device tree binding document for reboot-mode driver
Signed-off-by: Andy Yan <andy.yan@xxxxxxxxxxxxxx>
---
Changes in v2: None
Changes in v1: None
.../bindings/power/reset/reboot-mode.txt | 41 +++++++++++++++++
.../bindings/power/reset/syscon-reboot-mode.txt | 52 ++++++++++++++++++++++
2 files changed, 93 insertions(+)
create mode 100644 Documentation/devicetree/bindings/power/reset/reboot-mode.txt
create mode 100644 Documentation/devicetree/bindings/power/reset/syscon-reboot-mode.txt
diff --git a/Documentation/devicetree/bindings/power/reset/reboot-mode.txt b/Documentation/devicetree/bindings/power/reset/reboot-mode.txt
new file mode 100644
index 0000000..81d9f66
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/reset/reboot-mode.txt
@@ -0,0 +1,41 @@
+Generic reboot mode core map driver
+
+This driver get reboot mode arguments and call the write
+interface to stores the magic value in special register
+or ram . Then the bootloader can read it and take different
+action according to the argument stored.
+
+Required properties:
+- compatible: only support "syscon-reboot-mode" now.
+
+Each mode is represented as a sub-node of reboot_mode:
+
+Subnode required properties:
+- linux,mode: reboot mode command,such as "loader", "recovery", "fastboot".
+- loader,magic: magic number for the mode, this is vendor specific.
+
+Example:
+ reboot_mode {
reboot-mode instead please.
Sorry, I have already correct it in DT file, forget it here. It
will be changed in next version.
+ compatible = "syscon-reboot-mode";
+ offset = <0x40>;
This doc by itself is a little confusing. For example, is a child of the
syscon node? I would remove offset (and perhaps compatible) from this
example.
Yes, is a child of a syscon mapped node. For example, Rockchip
platform use a register of PMU(rk3066/rk3288) or GRF(rk3036), PMU and
GRF are aleady mapped by syscon.
offset and compatible are used by write interface driver like
syscon-reboot-mode.c. If you don't like it appear in the core map doc, I
will move it to the syscon-reboot-mode.txt?
+
+ loader {
+ linux,mode = "loader";
+ loader,magic = <BOOT_LOADER>;
+ };
Sorry, my previous suggestion was not clear. I'm suggesting get rid of
the subnodes and just do properties like this:
loader = <BOOT_LOADER>;
maskrom = <BOOT_MASKROM>;
That's the same amount of information unless node names and linux,mode
values are going to diverge. Do they need to? I can't see a reason.
Because the command"linux,mode" and value"loader,magic" is vendor
specific. I don't know what commands and how many mode other platform
will use. So as John says in his reply, this sort of flexibility help us
adapt the driver to different hardware/system environments.
We need to be clear what loader means. More specifically, it is boot
into bootloader shell.
Actually, Rockchip platform will reboot into a bootloader download
mode with this command. This mode can download faster than maskrom
download mode.
+
+ maskrom {
In theory, the bootrom could have multiple modes. This typically means a
USB download mode. So perhaps a more precise name would be
"rom-download".
In chips I'm familiar with the bootrom mode is selected via a different
mechanism than the secondary bootloader modes, but I suppose the same
mechanism could be used.
Yes , they use the same mechanism.
+ linux,mode = "maskrom";
+ loader,magic = <BOOT_MASKROM>;
+ };
+
+ recovery {
+ linux,mode = "recovery";
+ loader,magic = <BOOT_RECOVERY>;
+ };
+
+ fastboot {
+ linux,mode = "fastboot";
+ loader,magic = <BOOT_FASTBOOT>;
+ };
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