sandbox: Enhance map_to_sysmem() to handle foreign pointers

At present map_sysmem() maps an address into the sandbox RAM buffer,
return a pointer, while map_to_sysmem() goes the other way.

The mapping is currently just 1:1 since a case was not found where a more
flexible mapping was needed. PCI does have a separate and more complex
mapping, but uses its own mechanism.

However this arrange cannot handle one important case, which is where a
test declares a stack variable and passes a pointer to it into a U-Boot
function which uses map_to_sysmem() to turn it into a address. Since the
pointer is not inside emulated DRAM, this will fail.

Add a mapping feature which can handle any such pointer, mapping it to a
simple tag value which can be passed around in U-Boot as an address.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/sandbox/cpu/state.c b/arch/sandbox/cpu/state.c
index cc50819ab9..04a11fed55 100644
--- a/arch/sandbox/cpu/state.c
+++ b/arch/sandbox/cpu/state.c
@@ -359,6 +359,14 @@ void state_reset_for_test(struct sandbox_state *state)
 
 	memset(&state->wdt, '\0', sizeof(state->wdt));
 	memset(state->spi, '\0', sizeof(state->spi));
+
+	/*
+	 * Set up the memory tag list. Use the top of emulated SDRAM for the
+	 * first tag number, since that address offset is outside the legal
+	 * range, and can be assumed to be a tag.
+	 */
+	INIT_LIST_HEAD(&state->mapmem_head);
+	state->next_tag = state->ram_size;
 }
 
 int state_init(void)