[PATCH v2 1/9] dm: core: Allow marking driver model as dead

[Simon Glass]

On x86 devices we use CAR (Cache-As-RAM) to hold the malloc() region in
SPL, since SDRAM is not set up yet. This means that driver model stores
its tables in this region.

When preparing to jump from SPL to U-Boot proper, we must disable CAR, so
that the CPU can uses the caches normally. This means that driver model
tables become inaccessible. From there until we jump to U-Boot proper, we
must avoid using driver model.

This is only a problem on boards which operate this way, for example
chromebook_link64

Add a flag to indicate that driver model is dead and should not be used.
It can be used in SPL to avoid hanging the machine.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

Changes in v2:
- Add new patch to allow marking driver model as dead

 common/spl/spl.c                  | 2 +-
 include/asm-generic/global_data.h | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/common/spl/spl.c b/common/spl/spl.c
index 0062f3f45d9a..045a5e89625d 100644
--- a/common/spl/spl.c
+++ b/common/spl/spl.c
@@ -800,7 +800,7 @@ void board_init_r(gd_t *dummy1, ulong dummy2)
 	    IS_ENABLED(CONFIG_SPL_ATF))
 		dram_init_banksize();
 
-	if (CONFIG_IS_ENABLED(PCI)) {
+	if (CONFIG_IS_ENABLED(PCI) && !(gd->flags & GD_FLG_DM_DEAD)) {
 		ret = pci_init();
 		if (ret)
 			puts(SPL_TPL_PROMPT "Cannot initialize PCI\n");
diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index 8fc205ded1a3..5b11cb17ac03 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -667,6 +667,11 @@ enum gd_flags {
 	 * @GD_FLG_OF_TAG_MIGRATE: Device tree has old u-boot,dm- tags
 	 */
 	GD_FLG_OF_TAG_MIGRATE = 0x200000,
+	/**
+	 * @GD_FLG_DM_DEAD: Driver model is not accessible. This can be set when
+	 * the memory used to holds its tables has been mapped out.
+	 */
+	GD_FLG_DM_DEAD = 0x400000,
 };
 
 #endif /* __ASSEMBLY__ */
-- 
2.42.0.283.g2d96d420d3-goog