Hi Scott,
On Sat, Jan 23, 2016 at 9:11 AM, Scott Wood oss@buserror.net wrote:
On Fri, 2016-01-15 at 17:22 +1300, Chris Packham wrote:
Claim the MPP pins for the NAND flash controller only when it's actually being used. This allows the pins to be shared with the SPI interface which already supports an equivalent on-access MPP reconfiguration.
Reviewed-by: Mark Tomlinson mark.tomlinson@alliedtelesis.co.nz Signed-off-by: Chris Packham judge.packham@gmail.com
I haven't wrapped this with a configuration option because I think it should be safe to enable by default. It will either re-apply the same MPP configuration that has already been done in the board init or put the MPP pins into the correct mode to access NAND.
I've only got access to one kirkwood based board with NAND flash so I'd appreciate some feedback from someone with access to a few different boards.
From the datasheets I have access to it looks like there is only one possible MPP configuration for NF_IO[0-7] so that is what I've implemented. I'm not aware of anything using this driver that needs a different MPP config.
drivers/mtd/nand/kirkwood_nand.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)
diff --git a/drivers/mtd/nand/kirkwood_nand.c b/drivers/mtd/nand/kirkwood_nand.c index 4fc34d6..ff81212 100644 --- a/drivers/mtd/nand/kirkwood_nand.c +++ b/drivers/mtd/nand/kirkwood_nand.c @@ -9,6 +9,7 @@ #include <common.h> #include <asm/io.h> #include <asm/arch/soc.h> +#include <asm/arch/mpp.h> #include <nand.h>
/* NAND Flash Soc registers */ @@ -22,6 +23,8 @@ struct kwnandf_registers { static struct kwnandf_registers *nf_reg = (struct kwnandf_registers *)KW_NANDF_BASE;
+static u32 nand_mpp_backup[9] = { 0 };
There's a non-static nand_mpp_backup[] in drivers/spi/kirkwood_spi.c, with a different length. And the length assumed by kirkwood_mpp_conf seems to be different still (and larger than the spi array).
I assume you mean "u32 spi_mpp_backup[4];". The length of the backup reflects the pins that are being changed. In kirkwood_spi it's configuring SPI_CK, SPI_MSIO, SPI_MOSI. So spi_mpp_config[4] reflects these 3 pin settings plus an empty end marker, spi_mpp_backup[4] is symmetrical although possibly only 3 are necessary.
In the nand case there are 8 NF_IO pins, hence the array sizes are 8+1.
kirkwood_mpp_conf doesn't enforce any particular size for mpp_save it is required to be at least as big as mpp_list.
/*
- hardware specific access to control-lines/bits
*/ @@ -49,6 +52,22 @@ static void kw_nand_hwcontrol(struct mtd_info *mtd, int cmd, void kw_nand_select_chip(struct mtd_info *mtd, int chip) { u32 data;
u32 nand_config[] = {MPP0_NF_IO2,MPP1_NF_IO3,MPP2_NF_IO4,MPP3_NF_IO5,MPP4_NF_IO6,MPP5_NF_IO7,MPP18_NF_IO0,MPP19_NF_IO1,0};If you make this static const the compiler won't need to create the table at runtime.
Agreed. Will do in v2.
-Scott