[PATCH 2/3] mtd: rawnand: rzn1: Add new NAND controller driver

[Phil Edworthy]

Hi Miquel,

Thanks for your patches.

> Introduce Renesas RZ/N1x NAND controller driver which supports:
> - All ONFI timing modes
> - Different configurations of its internal ECC controller
> - On-die (not tested) and software ECC support
> - Several chips (not tested)
> - Subpage accesses
> - DMA and PIO
> 
> Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
> ---
It might be worth mentioning that this controller was originally provided
by Evatronix, then Cadence bought the Evatronix IP business.


> +	rzn1_nand->tim_gen_seq2 =
> +		TIM_GEN_SEQ2_D8(TO_CYCLES64(sdr->tRR_min + sdr->tREA_max,
> period_ns)) |
> +		TIM_GEN_SEQ2_D9(TO_CYCLES64(sdr->tRR_min, period_ns)) |
> +		TIM_GEN_SEQ2_D10(TO_CYCLES64(cle - cyc, period_ns)) |
> +		TIM_GEN_SEQ2_D11(TO_CYCLES64(bef_dly, period_ns));
In our out-of-tree driver for this controller [1], we allowed time for
the signal to propagate through the RZ/N1 io buffers; We just added 5ns
to all the timings. Don't you need to do something similar? I vaguely
recall that some values programmed to 0 caused issues.


> +static int rzn1_nand_chip_init(struct rzn1_nfc *nfc, struct device_node
...
> +	for (i = 0; i < nsels; i++) {
> +		ret = of_property_read_u32_index(np, "reg", i, &cs);
> +		if (ret) {
> +			dev_err(nfc->dev, "Incomplete reg property (%d)\n",
> +				ret);
> +			return ret;
> +		}
Check cs is <= nr of bits in assigned_cs.


> +static int rzn1_nfc_probe(struct platform_device *pdev) {
...
> +	nfc->regs = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(nfc->regs))
> +		return PTR_ERR(nfc->regs);
> +
> +	rzn1_nfc_dis_interrupts(nfc);
You need to enable the clock before writing to the registers.


> +static struct platform_driver rzn1_nfc_driver = {
> +	.driver = {
> +		.name   = "renesas-nfc",
nit: whitespace

btw, there was an attempt to upstream a driver for this IP a few years back, see [2]

Thanks
Phil

[1] https://github.com/renesas-rz/rzn1_linux/blob/rzn1-stable-v4.19/drivers/mtd/nand/raw/evatronix_nand.c
[2] https://patchwork.ozlabs.org/patch/629096/