Re: [PATCH v6 16/30] mtd: rawnand: timings: Use default values for tPROG_max and tBERS_max

[Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>]

On Fri, 29 May 2020 01:15:58 +0200
Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:

> The ONFI parameter page of a chip might define more fine grained
> tPROG_max and tBERS_max. When we do not have this information, we
> default to the highest possible values (they are maxima anyway).
> 
> There is no point setting these fields at runtime, so explicitly move
> these defaults to the main ONFI SDR timings structure.

And most importantly you want to do that to return a pointer to mode 0
directly :P.

> 
> Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>

Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>

> ---
>  drivers/mtd/nand/raw/nand_timings.c | 31 ++++++++++++++++++-----------
>  1 file changed, 19 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/nand_timings.c b/drivers/mtd/nand/raw/nand_timings.c
> index 728a2dee1eed..9ff4b121ab1e 100644
> --- a/drivers/mtd/nand/raw/nand_timings.c
> +++ b/drivers/mtd/nand/raw/nand_timings.c
> @@ -12,6 +12,13 @@
>  
>  #define ONFI_DYN_TIMING_MAX U16_MAX
>  
> +/*
> + * For non-ONFI chips we use the highest possible value for tPROG and tBERS.
> + * tR and tCCS will take the default values precised in the ONFI specification
> + * for timing mode 0, respectively 200us and 500ns.
> + *
> + * These four values are tweaked to be more accurate in the case of ONFI chips.
> + */
>  static const struct nand_data_interface onfi_sdr_timings[] = {
>  	/* Mode 0 */
>  	{
> @@ -20,6 +27,8 @@ static const struct nand_data_interface onfi_sdr_timings[] = {
>  		.timings.sdr = {
>  			.tCCS_min = 500000,
>  			.tR_max = 200000000,
> +			.tPROG_max = 1000000ULL * ONFI_DYN_TIMING_MAX,
> +			.tBERS_max = 1000000ULL * ONFI_DYN_TIMING_MAX,
>  			.tADL_min = 400000,
>  			.tALH_min = 20000,
>  			.tALS_min = 50000,
> @@ -63,6 +72,8 @@ static const struct nand_data_interface onfi_sdr_timings[] = {
>  		.timings.sdr = {
>  			.tCCS_min = 500000,
>  			.tR_max = 200000000,
> +			.tPROG_max = 1000000ULL * ONFI_DYN_TIMING_MAX,
> +			.tBERS_max = 1000000ULL * ONFI_DYN_TIMING_MAX,
>  			.tADL_min = 400000,
>  			.tALH_min = 10000,
>  			.tALS_min = 25000,
> @@ -106,6 +117,8 @@ static const struct nand_data_interface onfi_sdr_timings[] = {
>  		.timings.sdr = {
>  			.tCCS_min = 500000,
>  			.tR_max = 200000000,
> +			.tPROG_max = 1000000ULL * ONFI_DYN_TIMING_MAX,
> +			.tBERS_max = 1000000ULL * ONFI_DYN_TIMING_MAX,
>  			.tADL_min = 400000,
>  			.tALH_min = 10000,
>  			.tALS_min = 15000,
> @@ -149,6 +162,8 @@ static const struct nand_data_interface onfi_sdr_timings[] = {
>  		.timings.sdr = {
>  			.tCCS_min = 500000,
>  			.tR_max = 200000000,
> +			.tPROG_max = 1000000ULL * ONFI_DYN_TIMING_MAX,
> +			.tBERS_max = 1000000ULL * ONFI_DYN_TIMING_MAX,
>  			.tADL_min = 400000,
>  			.tALH_min = 5000,
>  			.tALS_min = 10000,
> @@ -192,6 +207,8 @@ static const struct nand_data_interface onfi_sdr_timings[] = {
>  		.timings.sdr = {
>  			.tCCS_min = 500000,
>  			.tR_max = 200000000,
> +			.tPROG_max = 1000000ULL * ONFI_DYN_TIMING_MAX,
> +			.tBERS_max = 1000000ULL * ONFI_DYN_TIMING_MAX,
>  			.tADL_min = 400000,
>  			.tALH_min = 5000,
>  			.tALS_min = 10000,
> @@ -235,6 +252,8 @@ static const struct nand_data_interface onfi_sdr_timings[] = {
>  		.timings.sdr = {
>  			.tCCS_min = 500000,
>  			.tR_max = 200000000,
> +			.tPROG_max = 1000000ULL * ONFI_DYN_TIMING_MAX,
> +			.tBERS_max = 1000000ULL * ONFI_DYN_TIMING_MAX,
>  			.tADL_min = 400000,
>  			.tALH_min = 5000,
>  			.tALS_min = 10000,
> @@ -357,18 +376,6 @@ int onfi_fill_data_interface(struct nand_chip *chip,
>  
>  		/* nanoseconds -> picoseconds */
>  		timings->tCCS_min = 1000UL * onfi->tCCS;
> -	} else {
> -		struct nand_sdr_timings *timings = &iface->timings.sdr;
> -		/*
> -		 * For non-ONFI chips we use the highest possible value for
> -		 * tPROG and tBERS. tR and tCCS will take the default values
> -		 * precised in the ONFI specification for timing mode 0,
> -		 * respectively 200us and 500ns.
> -		 */
> -
> -		/* microseconds -> picoseconds */
> -		timings->tPROG_max = 1000000ULL * ONFI_DYN_TIMING_MAX;
> -		timings->tBERS_max = 1000000ULL * ONFI_DYN_TIMING_MAX;
>  	}
>  
>  	return 0;


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