mtd: physmap_of: add a hook for Intel IXP4xx flash probing

In order to support device tree probing of IXP4xx NOR flash
chips, a certain big-endian or mixed-endian memory access
pattern need to be used.

I have opted to use the pattern set by previous plug-ins
to physmap for Gemini and Versatile, just override some
functions and reuse most of the physmap core code as it
is to minimize maintenance.

Parts of drivers/mtd/ixp4xx.c are copied into this file.

After we have IXP4xx converted fully to device tree, the
drivers/mtd/ixp4xx.c file will be deleted and this will
be the only access pattern to the IXP4xx flash.

I did not keep the quirk in the flash write function
after probe, where the old code for a while checks for
access to odd addresses, fails and assigns a "faster"
write function once it has convinced probe to only use
2-byte accesses. As we mandate that this device should
be using bank-width = <2> this should not be a problem
unless misconfigured.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/mtd/maps/physmap-core.c b/drivers/mtd/maps/physmap-core.c
index 21b556afc305..a9f7964e2edb 100644
--- a/drivers/mtd/maps/physmap-core.c
+++ b/drivers/mtd/maps/physmap-core.c
@@ -41,6 +41,7 @@
 #include <linux/gpio/consumer.h>
 
 #include "physmap-gemini.h"
+#include "physmap-ixp4xx.h"
 #include "physmap-versatile.h"
 
 struct physmap_flash_info {
@@ -370,6 +371,10 @@ static int physmap_flash_of_init(struct platform_device *dev)
 		if (err)
 			return err;
 
+		err = of_flash_probe_ixp4xx(dev, dp, &info->maps[i]);
+		if (err)
+			return err;
+
 		err = of_flash_probe_versatile(dev, dp, &info->maps[i]);
 		if (err)
 			return err;