Re: [PATCH 2/2] mtd: msm_nand: Add initial msm nand driver support.

From: Murali Nalajala
Date: Sat Apr 16 2011 - 06:15:13 EST


On 4/16/2011 2:01 PM, Artem Bityutskiy wrote:
On Sat, 2011-04-16 at 11:20 +0300, Artem Bityutskiy wrote:
+#define MSM_NAND_REG(off) (msm_nand_phys + (off))
+
+#define MSM_NAND_FLASH_CMD MSM_NAND_REG(0x0000)
+#define MSM_NAND_ADDR0 MSM_NAND_REG(0x0004)

Could you please make the macros to take the "struct msm_nand_chip
*chip" argument instead, and store the pase address there. Do not hide
the fact that those macros are actually functions, not constant - this
is error prone.

Besides, I'm do not know your HW, but if you have several controllers
with various base addresses - your driver won't work.

you are correct, we have multiple controllers, which breaks this logic
in future.

So then make your macros to accept the base address as an argument
instead please.

Or better make macros to be constants, and always use something like
base + MSM_NAND_FLASH_CMD - this is the standard approach.

Here all the registers expands to 'base + register offset'.
In the code we are directly using the macro names (these are register names on my controller) i.e. MSM_NAND_FLASH_CMD & MSM_NAND_ADDR0 without thinking of what the controller base is and what controller it is.

Currently, this code we have targeted for the single NAND controller solution for some of the MSM's. There are other targets which uses multiple NAND controllers which we haven't done much work yet to submit those patches.

Thanks,
Murali N

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