[U-Boot] [PATCH v3 3/5] dm: ns16550: Don't map_physmem for I/O ports

Paul Burton paul.burton at imgtec.com
Tue May 17 08:43:26 CEST 2016


If the UART is to be accessed using I/O port accessors (inb & outb) then
using map_physmem doesn't make sense, since it operates in a different
memory space. Remove the call to map_physmem when
CONFIG_SYS_NS16550_PORT_MAPPED is defined, allowing I/O port addresses
to not be mangled by the incorrect mapping.

Signed-off-by: Paul Burton <paul.burton at imgtec.com>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck at gmail.com>
Tested-by: Daniel Schwierzeck <daniel.schwierzeck at gmail.com>
---

Changes in v3: None
Changes in v2:
- New patch, part of a simplified approach tackling only a single Malta UART.

 drivers/serial/ns16550.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
index 28da9dd..e58e6aa 100644
--- a/drivers/serial/ns16550.c
+++ b/drivers/serial/ns16550.c
@@ -100,7 +100,11 @@ static void ns16550_writeb(NS16550_t port, int offset, int value)
 	unsigned char *addr;
 
 	offset *= 1 << plat->reg_shift;
+#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
+	addr = (unsigned char *)plat->base + offset;
+#else
 	addr = map_physmem(plat->base, 0, MAP_NOCACHE) + offset;
+#endif
 	/*
 	 * As far as we know it doesn't make sense to support selection of
 	 * these options at run-time, so use the existing CONFIG options.
@@ -114,7 +118,11 @@ static int ns16550_readb(NS16550_t port, int offset)
 	unsigned char *addr;
 
 	offset *= 1 << plat->reg_shift;
+#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
+	addr = (unsigned char *)plat->base + offset;
+#else
 	addr = map_physmem(plat->base, 0, MAP_NOCACHE) + offset;
+#endif
 
 	return serial_in_shift(addr + plat->reg_offset, plat->reg_shift);
 }
-- 
2.8.2



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