Hi Harald,
On Wed, Feb 17, 2016 at 07:14:56PM +0100, Harald Welte wrote:
> Dear List,
>
> I have a custom board with an AM335x on it. We used to have an I2C
> EEPROM for keeping the boot state, but moved that to SPI in a subsequent
> version.
>
> The SPI EEPROM uses gpio-based chip select, which is supported by linux
> kernel spi-omap2-mcspi.c. However, it is not supported by barebox.
>
> My "solution" was to simply use the gpio-bitbang in barebox, which also
> works fine for those few bytes that need to be read, performance doesn't
> matter.
>
> Now however I can no longer boot any kernel image, as of_state_fixup
> fails in
>
> backend_node = of_find_node_by_path_from(root, state->backend->of_path);
In newer versions we have:
commit b62aea561142c6974b593301fbec9ed18381cf8d
Author: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Date: Thu Sep 10 15:11:28 2015 +0200
of_fix_tree: do not fail when fixup fails
So at least a failed of_fixup should no longer prevent you from booting.
>
> due to the fact that the of-path of the EEPROM is different in the
> barebox device tree (/spi_gpio/m95m02@0) than in the kernel device tree
> (/ocp/spi@481a0000/m95m02@0)
>
> Is there any designated solution for this situation?
We could introduce a state.of_backend_path variable which holds the
path, something like attached. You would then have to change the
variable to the correct path somewhere.
Another way I could think of would be to add a possibility to blacklist
of_fixups. That would do it aswell since you could provide a correct
device tree for the kernel, right?
Sascha
-----------------------------8<-------------------------------
diff --git a/common/state.c b/common/state.c
index 3e95efd..223d00d 100644
--- a/common/state.c
+++ b/common/state.c
@@ -56,7 +56,7 @@ struct state {
struct state_backend {
int (*save)(struct state_backend *backend, struct state *state);
const char *name;
- const char *of_path;
+ char *of_path;
const char *path;
struct digest *digest;
};
@@ -1642,6 +1642,7 @@ int state_backend_raw_file(struct state *state, const char *of_path,
struct state_backend *backend;
struct state_variable *sv;
struct mtd_info_user meminfo;
+ struct param_d *p;
size_t path_size = 0;
int ret;
@@ -1680,6 +1681,13 @@ int state_backend_raw_file(struct state *state, const char *of_path,
state->backend = backend;
+ p = dev_add_param_string(&state->dev, "of_backend_path", NULL, NULL,
+ &state->backend->of_path, NULL);
+ if (IS_ERR(p)) {
+ ret = PTR_ERR(p);
+ goto err;
+ }
+
ret = mtd_get_meminfo(backend->path, &meminfo);
if (!ret && !(meminfo.flags & MTD_NO_ERASE)) {
backend_raw->need_erase = true;
--
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