[PATCH 3/4] lib: logic_pio: Introduce MMIO_LOWER_RESERVED

[Jiaxun Yang]

That would allow platforms reserve some lower address in PIO MMIO range
to deal with legacy drivers with hardcoded I/O ports that can't be
managed by logic_pio.

Signed-off-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
---
 lib/logic_pio.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/logic_pio.c b/lib/logic_pio.c
index f511a99bb389..57fff1cb7063 100644
--- a/lib/logic_pio.c
+++ b/lib/logic_pio.c
@@ -20,6 +20,10 @@
 static LIST_HEAD(io_range_list);
 static DEFINE_MUTEX(io_range_mutex);
 
+#ifndef MMIO_LOWER_RESERVED
+#define MMIO_LOWER_RESERVED	0
+#endif
+
 /* Consider a kernel general helper for this */
 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
 
@@ -36,7 +40,7 @@ int logic_pio_register_range(struct logic_pio_hwaddr *new_range)
 	struct logic_pio_hwaddr *range;
 	resource_size_t start;
 	resource_size_t end;
-	resource_size_t mmio_end = 0;
+	resource_size_t mmio_end = MMIO_LOWER_RESERVED;
 	resource_size_t iio_sz = MMIO_UPPER_LIMIT;
 	int ret = 0;
 
-- 
2.26.0.rc2