New patch to review for coreboot: ipq806x/storm: Return NULL for cbmem_top if DRAM is not initialized

[Furquan Shaikh]

Furquan Shaikh ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/14182

-gerrit

commit 80e2164df7b342e6504196c729ef82a1cad04342
Author: Furquan Shaikh 
Date:   Mon Mar 28 13:29:33 2016 -0700

ipq806x/storm: Return NULL for cbmem_top if DRAM is not initialized

DRAM initialization on storm requires ipq blobs to be
    loaded from cbfs. vboot_locator first checks cbmem_find to see if cbmem is
    initialized and contains selected region info, else it falls back to
    vboot work buffer.

Since cbmem_find calls into cbmem_top to identify the location of
    cbmem area, board/chipset is expected to return NULL until the backing
    store is ready, which in this case until DRAM is initialized in
    romstage, return NULL for cbmem_top.

Change-Id: I1880ce61dcfdabaa527d7a6dcc3482dfe5d5fd17
    Signed-off-by: Furquan Shaikh 
---
 src/mainboard/google/storm/romstage.c               |  3 +++
 src/soc/qualcomm/ipq806x/cbmem.c                    | 16 ++++++++++++++++
 src/soc/qualcomm/ipq806x/include/soc/soc_services.h |  3 +++
 3 files changed, 22 insertions(+)

diff --git a/src/mainboard/google/storm/romstage.c b/src/mainboard/google/storm/romstage.c
index c1b8654..a5438e1 100644
--- a/src/mainboard/google/storm/romstage.c
+++ b/src/mainboard/google/storm/romstage.c
@@ -28,6 +28,9 @@ void main(void)
    /* Add dram mappings to mmu tables. */
    setup_dram_mappings(DRAM_INITIALIZED);

+	ipq_cbmem_backing_store_ready();
+
    cbmem_initialize_empty();
+
    run_ramstage();
 }
diff --git a/src/soc/qualcomm/ipq806x/cbmem.c b/src/soc/qualcomm/ipq806x/cbmem.c
index 7aff231..05325cc 100644
--- a/src/soc/qualcomm/ipq806x/cbmem.c
+++ b/src/soc/qualcomm/ipq806x/cbmem.c
@@ -16,7 +16,23 @@
 #include <cbmem.h>
 #include <soc/soc_services.h>

+static int cbmem_backing_store_ready;
+
+void ipq_cbmem_backing_store_ready(void)
+{
+	cbmem_backing_store_ready = 1;
+}
+
 void *cbmem_top(void)
 {
+	/*
+	 * In romstage, make sure that cbmem backing store is ready before
+	 * returning pointer to cbmem top. Otherwise, it could lead to issues
+	 * with components that utilize cbmem in romstage (e.g. vboot_locator
+	 * for loading ipq blobs before DRAM is initialized).
+	 */
+	if (ENV_ROMSTAGE && (cbmem_backing_store_ready == 0))
+		return NULL;
+
    return _memlayout_cbmem_top;
 }
diff --git a/src/soc/qualcomm/ipq806x/include/soc/soc_services.h b/src/soc/qualcomm/ipq806x/include/soc/soc_services.h
index 7006b82..e7a6d68 100644
--- a/src/soc/qualcomm/ipq806x/include/soc/soc_services.h
+++ b/src/soc/qualcomm/ipq806x/include/soc/soc_services.h
@@ -32,4 +32,7 @@ int tz_init_wrapper(int, int, void *);
 /* Load RPM code into memory and trigger its execution. */
 void start_rpm(void);

+/* Mark cbmem backing store as ready. */
+void ipq_cbmem_backing_store_ready(void);
+
 #endif