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Commit 2d43457f authored by Boris Brezillon's avatar Boris Brezillon
Browse files

mtd: nand: sunxi: fix EDO mode selection 



The ONFI spec says that EDO should be enabled if the host drives tRC less
than 30ns, but the code just tests for the tRC_min value extracted from
the timings exposed by the NAND chip not the timings actually configured
in the NAND controller.
Fix that by first rounding down the requested clk_rate with
clk_round_rate() and then checking if tRC is actually smaller than 30ns.

Signed-off-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
parent 2f9992e0

drivers/mtd/nand/sunxi_nand.c

+11 −7
Original line number Diff line number Diff line
@@ -1100,6 +1100,7 @@ static int sunxi_nand_chip_set_timings(struct sunxi_nand_chip *chip, 
	struct sunxi_nfc *nfc = to_sunxi_nfc(chip->nand.controller);

	u32 min_clk_period = 0;

	s32 tWB, tADL, tWHR, tRHW, tCAD;

	long real_clk_rate;



	/* T1 <=> tCLS */

	if (timings->tCLS_min > min_clk_period)
@@ -1197,13 +1198,6 @@ static int sunxi_nand_chip_set_timings(struct sunxi_nand_chip *chip, 
	/* TODO: A83 has some more bits for CDQSS, CS, CLHZ, CCS, WC */

	chip->timing_cfg = NFC_TIMING_CFG(tWB, tADL, tWHR, tRHW, tCAD);



	/*

	 * ONFI specification 3.1, paragraph 4.15.2 dictates that EDO data

	 * output cycle timings shall be used if the host drives tRC less than

	 * 30 ns.

	 */

	chip->timing_ctl = (timings->tRC_min < 30000) ? NFC_TIMING_CTL_EDO : 0;



	/* Convert min_clk_period from picoseconds to nanoseconds */

	min_clk_period = DIV_ROUND_UP(min_clk_period, 1000);
@@ -1214,6 +1208,16 @@ static int sunxi_nand_chip_set_timings(struct sunxi_nand_chip *chip, 
	 * Allwinner engineers.

	 */

	chip->clk_rate = NSEC_PER_SEC / min_clk_period;

	real_clk_rate = clk_round_rate(nfc->mod_clk, chip->clk_rate);



	/*

	 * ONFI specification 3.1, paragraph 4.15.2 dictates that EDO data

	 * output cycle timings shall be used if the host drives tRC less than

	 * 30 ns.

	 */

	min_clk_period = NSEC_PER_SEC / real_clk_rate;

	chip->timing_ctl = ((min_clk_period * 2) < 30) ?

			   NFC_TIMING_CTL_EDO : 0;



	return 0;

}