From: Dario Binacchi dario.binacchi@amarulasolutions.com
[ Upstream commit 2970bf5a32f079e1e9197411db4fe9faccb1503a ]
Set the controller registers according to the real clock rate. The controller registers configuration (setup, hold, timeout, ... cycles) depends on the clock rate of the GPMI. Using the real rate instead of the ideal one, avoids that this inaccuracy (required_rate - real_rate) affects the registers setting.
This patch has been tested on two custom boards with i.MX28 and i.MX6 SOCs: - i.MX28: required rate 100MHz, real rate 99.3MHz - i.MX6 required rate 100MHz, real rate 99MHz
Fixes: b1206122069a ("mtd: rawnand: gpmi: use core timings instead of an empirical derivation") Co-developed-by: Michael Trimarchi michael@amarulasolutions.com Signed-off-by: Michael Trimarchi michael@amarulasolutions.com Signed-off-by: Dario Binacchi dario.binacchi@amarulasolutions.com Tested-by: Sascha Hauer s.hauer@pengutronix.de Reviewed-by: Sascha Hauer s.hauer@pengutronix.de Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com Link: https://lore.kernel.org/linux-mtd/20220118095434.35081-3-dario.binacchi@amar... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c index ab2f824abf54..02218c3b548f 100644 --- a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c +++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c @@ -645,6 +645,7 @@ static void gpmi_nfc_compute_timings(struct gpmi_nand_data *this, const struct nand_sdr_timings *sdr) { struct gpmi_nfc_hardware_timing *hw = &this->hw; + struct resources *r = &this->resources; unsigned int dll_threshold_ps = this->devdata->max_chain_delay; unsigned int period_ps, reference_period_ps; unsigned int data_setup_cycles, data_hold_cycles, addr_setup_cycles; @@ -668,6 +669,8 @@ static void gpmi_nfc_compute_timings(struct gpmi_nand_data *this, wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY; }
+ hw->clk_rate = clk_round_rate(r->clock[0], hw->clk_rate); + /* SDR core timings are given in picoseconds */ period_ps = div_u64((u64)NSEC_PER_SEC * 1000, hw->clk_rate);