[PATCH 1/2] lmb: Fix LMB_MEMORY_REGIONS flag usage

[Patrick Delaunay]

Remove test on CONFIG_LMB_MEMORY_REGIONS introduced by commit
7c1860fce4e3 ("lmb: Fix lmb property's defination under struct lmb").

This code in lmb_init() is strange, because if CONFIG_LMB_USE_MAX_REGIONS
and CONFIG_LMB_MEMORY_REGIONS are not defined, the implicit #else is empty
and the required initialization are not done:
lmb->memory.max = ?
lmb->reserved.max = ?

But this setting is not possible:
- CONFIG_LMB_USE_MAX_REGIONS not defined
- CONFIG_LMB_MEMORY_REGIONS not defined
because CONFIG_LMB_MEMORY_REGIONS and CONFIG_LMB_RESERVED_REGIONS are
defined as soon as the CONFIG_LMB_USE_MAX_REGIONS is not defined.

This patch removes this impossible case #elif and I add some
explanation in lmb.h to explain why in the struct lmb {} the lmb
property's should is defined if CONFIG_LMB_MEMORY_REGIONS is NOT defined.

Fixes: 5e2548c1d6e03 ("lmb: Fix LMB_MEMORY_REGIONS flag usage")
Reported-by: Mark Millard <marklmi at yahoo.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay at foss.st.com>
---

 include/lmb.h | 20 +++++++++++++++++++-
 lib/lmb.c     |  2 +-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/include/lmb.h b/include/lmb.h
index 7298c2ccc403..f70463ac5440 100644
--- a/include/lmb.h
+++ b/include/lmb.h
@@ -35,6 +35,24 @@ struct lmb_property {
 	enum lmb_flags flags;
 };
 
+/*
+ * For regions size management, see LMB configuration in KConfig
+ * all the #if test are done with CONFIG_LMB_USE_MAX_REGIONS (boolean)
+ *
+ * case 1. CONFIG_LMB_USE_MAX_REGIONS is defined (legacy mode)
+ *         => CONFIG_LMB_MAX_REGIONS is used to configure the region size,
+ *         direclty in the array lmb_region.region[], with the same
+ *         configuration for memory reion and reseserved region.
+ *
+ * case 2. CONFIG_LMB_USE_MAX_REGIONS is not defined, the size of each
+ *         region is configurated *independently* with
+ *         => CONFIG_LMB_MEMORY_REGIONS: struct lmb.memory_regions
+ *         => CONFIG_LMB_RESERVED_REGIONS: struct lmb.reserved_regions
+ *         lmb_region.region is only a pointer to the correct buffer,
+ *         initialized in lmb_init(). This configuration is useful to manage
+ *         more reserved memory regions with CONFIG_LMB_RESERVED_REGIONS.
+ */
+
 /**
  * struct lmb_region - Description of a set of region.
  *
@@ -68,7 +86,7 @@ struct lmb_region {
 struct lmb {
 	struct lmb_region memory;
 	struct lmb_region reserved;
-#ifdef CONFIG_LMB_MEMORY_REGIONS
+#if !IS_ENABLED(CONFIG_LMB_USE_MAX_REGIONS)
 	struct lmb_property memory_regions[CONFIG_LMB_MEMORY_REGIONS];
 	struct lmb_property reserved_regions[CONFIG_LMB_RESERVED_REGIONS];
 #endif
diff --git a/lib/lmb.c b/lib/lmb.c
index 2444b2a62121..8fbe453dfa9d 100644
--- a/lib/lmb.c
+++ b/lib/lmb.c
@@ -110,7 +110,7 @@ void lmb_init(struct lmb *lmb)
 #if IS_ENABLED(CONFIG_LMB_USE_MAX_REGIONS)
 	lmb->memory.max = CONFIG_LMB_MAX_REGIONS;
 	lmb->reserved.max = CONFIG_LMB_MAX_REGIONS;
-#elif defined(CONFIG_LMB_MEMORY_REGIONS)
+#else
 	lmb->memory.max = CONFIG_LMB_MEMORY_REGIONS;
 	lmb->reserved.max = CONFIG_LMB_RESERVED_REGIONS;
 	lmb->memory.region = lmb->memory_regions;
-- 
2.25.1