Commit e32df79f authored by Miquel Raynal's avatar Miquel Raynal
Browse files

mtd: rawnand: Add a helper to find the closest ONFI NV-DDR mode 



Introduce a similar helper to onfi_find_closest_sdr_mode(), but for
NV-DDR timings. It just takes a timing structure as parameter and
returns the closest mode by comparing all minimum timings. This is
useful for rigid controllers on which tuning the timings is not
possible.

Signed-off-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210505213750.257417-16-miquel.raynal@bootlin.com
parent 09cdb237

drivers/mtd/nand/raw/internals.h

+2 −0
Original line number Diff line number Diff line
@@ -90,6 +90,8 @@ void onfi_fill_interface_config(struct nand_chip *chip, 
				unsigned int timing_mode);

unsigned int

onfi_find_closest_sdr_mode(const struct nand_sdr_timings *spec_timings);

unsigned int

onfi_find_closest_nvddr_mode(const struct nand_nvddr_timings *spec_timings);

int nand_choose_best_sdr_timings(struct nand_chip *chip,

				 struct nand_interface_config *iface,

				 struct nand_sdr_timings *spec_timings);

drivers/mtd/nand/raw/nand_timings.c

+42 −0
Original line number Diff line number Diff line
@@ -601,6 +601,48 @@ onfi_find_closest_sdr_mode(const struct nand_sdr_timings *spec_timings) 
}



/**

 * onfi_find_closest_nvddr_mode - Derive the closest ONFI NVDDR timing mode

 *                                given a set of timings

 * @spec_timings: the timings to challenge

 */

unsigned int

onfi_find_closest_nvddr_mode(const struct nand_nvddr_timings *spec_timings)

{

	const struct nand_nvddr_timings *onfi_timings;

	int mode;



	for (mode = ARRAY_SIZE(onfi_nvddr_timings) - 1; mode > 0; mode--) {

		onfi_timings = &onfi_nvddr_timings[mode].timings.nvddr;



		if (spec_timings->tCCS_min <= onfi_timings->tCCS_min &&

		    spec_timings->tAC_min <= onfi_timings->tAC_min &&

		    spec_timings->tADL_min <= onfi_timings->tADL_min &&

		    spec_timings->tCAD_min <= onfi_timings->tCAD_min &&

		    spec_timings->tCAH_min <= onfi_timings->tCAH_min &&

		    spec_timings->tCALH_min <= onfi_timings->tCALH_min &&

		    spec_timings->tCALS_min <= onfi_timings->tCALS_min &&

		    spec_timings->tCAS_min <= onfi_timings->tCAS_min &&

		    spec_timings->tCEH_min <= onfi_timings->tCEH_min &&

		    spec_timings->tCH_min <= onfi_timings->tCH_min &&

		    spec_timings->tCK_min <= onfi_timings->tCK_min &&

		    spec_timings->tCS_min <= onfi_timings->tCS_min &&

		    spec_timings->tDH_min <= onfi_timings->tDH_min &&

		    spec_timings->tDQSCK_min <= onfi_timings->tDQSCK_min &&

		    spec_timings->tDQSD_min <= onfi_timings->tDQSD_min &&

		    spec_timings->tDS_min <= onfi_timings->tDS_min &&

		    spec_timings->tDSC_min <= onfi_timings->tDSC_min &&

		    spec_timings->tRHW_min <= onfi_timings->tRHW_min &&

		    spec_timings->tRR_min <= onfi_timings->tRR_min &&

		    spec_timings->tWHR_min <= onfi_timings->tWHR_min &&

		    spec_timings->tWRCK_min <= onfi_timings->tWRCK_min &&

		    spec_timings->tWW_min <= onfi_timings->tWW_min)

			return mode;

	}



	return 0;

}



/*

 * onfi_fill_sdr_interface_config - Initialize a SDR interface config from a

 *                                  given ONFI mode

 * @chip: The NAND chip