Franklin, Tony,

On 11/03/16 17:39, Franklin S Cooper Jr. wrote:

On 03/11/2016 07:52 AM, Roger Quadros wrote:

quoted

Franklin,

On 11/03/16 01:56, Franklin S Cooper Jr wrote:

quoted

The dma channel information is located within the GPMC node which is the
NAND's parent node. The NAND driver requires a handle to the GPMC's dev
to properly parse the DMA properties. Therefore, set the NAND's parent dev
to the GPMC's dev so it can be referenced within the driver.

Signed-off-by: Franklin S Cooper Jr <redacted>
---
Version 4 changes:
Instead of storing the GPMC dev in a new property simply grab a reference
to it and set omap2-nand's dev.parent to it.

 arch/arm/mach-omap2/gpmc-nand.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-omap2/gpmc-nand.c b/arch/arm/mach-omap2/gpmc-nand.c
index 72918c4..77e453c 100644
--- a/arch/arm/mach-omap2/gpmc-nand.c
+++ b/arch/arm/mach-omap2/gpmc-nand.c

@@ -15,6 +15,7 @@
 #include <linux/omap-gpmc.h>
 #include <linux/mtd/nand.h>
 #include <linux/platform_data/mtd-nand-omap2.h>
+#include <linux/of_platform.h>
 
 #include <asm/mach/flash.h>
 

@@ -77,6 +78,9 @@ int gpmc_nand_init(struct omap_nand_platform_data *gpmc_nand_data,
 	int err	= 0;
 	struct gpmc_settings s;
 	struct platform_device *pdev;
+	struct platform_device *gpmc_dev;
+	struct device_node *gpmc_node;
+
 	struct resource gpmc_nand_res[] = {
 		{ .flags = IORESOURCE_MEM, },
 		{ .flags = IORESOURCE_IRQ, },

@@ -134,8 +138,18 @@ int gpmc_nand_init(struct omap_nand_platform_data *gpmc_nand_data,
 	if (pdev) {
 		err = platform_device_add_resources(pdev, gpmc_nand_res,
 						    ARRAY_SIZE(gpmc_nand_res));
-		if (!err)
+		if (!err) {
 			pdev->dev.platform_data = gpmc_nand_data;
+
+			gpmc_node = of_get_parent(gpmc_nand_data->of_node);

I'm afraid that we can't use this method as we want to restrict
gpmc_nand_init() to non-DT boots.

The only users of the parent GPMC driver are already using
DT. The gpmc_probe_nand_child function in the GPMC driver
which calls gpmc_nand_init is already DT only.

The only other caller to gpmc_nand_init is board-flash.c.
The driver doesn't utilize xfer_type to even switch to any
other modes including DMA prefetch mode.  Looking at it
closer there isn't a dev from some kind of parent for me to
pass along. Board_nand_init which calls gpmc_nand_init just
takes raw NAND values with no relation to its parent.


With that being said are you ok with leaving it as is?

I think it is OK to assume that NAND DMA won't work with legacy boot.
Tony any objections? I see that board-ldp.c is the only legacy user
of NAND. When can we drop support for it?

I want to keep gpmc_nand_init() as it is and don't want to add any
device tree specific calls here.

So I think it is still best if you rebase your series on top of [1]
so that you are assured NAND controller's parent is the GPMC device
in the DT case without requiring the $subject patch.

[1] https://lkml.org/lkml/2016/2/19/599
The series has been Acked by all maintainers and will go in v4.6

cheers,
-roger