linux-kernel - RE: [LINUX PATCH v11 3/3] mtd: rawnand: arasan: Add support for Arasan NAND Flash Controller

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Date:   Fri, 19 Oct 2018 09:44:41 +0000
From:   Naga Sureshkumar Relli <nagasure@...inx.com>
To:     Boris Brezillon <boris.brezillon@...tlin.com>
CC:     "miquel.raynal@...tlin.com" <miquel.raynal@...tlin.com>,
        "richard@....at" <richard@....at>,
        "dwmw2@...radead.org" <dwmw2@...radead.org>,
        "computersforpeace@...il.com" <computersforpeace@...il.com>,
        "marek.vasut@...il.com" <marek.vasut@...il.com>,
        Michal Simek <michals@...inx.com>,
        "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "nagasuresh12@...il.com" <nagasuresh12@...il.com>
Subject: RE: [LINUX PATCH v11 3/3] mtd: rawnand: arasan: Add support for
 Arasan NAND Flash Controller

Hi Boris,

Sorry for the late reply.
I am busy with some other work.

> -----Original Message-----
> From: Boris Brezillon [mailto:boris.brezillon@...tlin.com]
> Sent: Thursday, October 4, 2018 1:09 AM
> To: Naga Sureshkumar Relli <nagasure@...inx.com>
> Cc: miquel.raynal@...tlin.com; richard@....at; dwmw2@...radead.org;
> computersforpeace@...il.com; marek.vasut@...il.com; Michal Simek
> <michals@...inx.com>; linux-mtd@...ts.infradead.org; linux-kernel@...r.kernel.org;
> nagasuresh12@...il.com
> Subject: Re: [LINUX PATCH v11 3/3] mtd: rawnand: arasan: Add support for Arasan
> NAND Flash Controller
> 
> Hi Naga,
> 
> On Tue, 25 Sep 2018 17:50:31 +0530
> Naga Sureshkumar Relli <naga.sureshkumar.relli@...inx.com> wrote:
> 
> > +static int anfc_read_param_get_feature_sp_read_type_exec(struct nand_chip *chip,
> > +							 const struct nand_subop
> > +							 *subop)
> > +{
> > +	const struct nand_op_instr *instr;
> > +	struct anfc_nand_controller *nfc = to_anfc(chip->controller);
> > +	unsigned int op_id, len;
> > +	struct anfc_op nfc_op = {};
> > +	struct mtd_info *mtd = nand_to_mtd(chip);
> > +	struct anfc_nand_chip *achip = to_anfc_nand(chip);
> > +	u32 dma_mode, addrcycles, write_size;
> > +
> > +	anfc_parse_instructions(chip, subop, &nfc_op);
> > +	instr = nfc_op.data_instr;
> > +	op_id = nfc_op.data_instr_idx;
> > +
> > +	if (nfc_op.cmds[0] == NAND_CMD_PARAM) {
> > +		nfc->prog = PROG_RDPARAM;
> > +		dma_mode = 0;
> > +		addrcycles = 1;
> > +		write_size = 0;
> > +	}
> > +	if (nfc_op.cmds[0] == NAND_CMD_GET_FEATURES) {
> > +		nfc->prog = PROG_GET_FEATURE;
> > +		dma_mode = 0;
> > +		addrcycles = 1;
> > +		write_size = 0;
> > +	}
> > +	if (nfc_op.cmds[0] == NAND_CMD_READ0) {
> > +		nfc->prog = PROG_PGRD;
> > +		addrcycles = achip->raddr_cycles + achip->caddr_cycles;
> > +		write_size = mtd->writesize;
> > +		dma_mode = 1;
> > +	}
> > +
> 
> Sorry, but I still don't understand why nfc->prog is different. Did you try using
> PROG_PGRD for all these ops? I mean, the sequence is the same, and you keep passing the
> opcode and the number of address cycles to the engine using other reg fields.
Yes, I tried it now with PROG_PGRD and I don't see any issues.
I will update the same in next version of patch.
Thanks for your suggestion.

> 
> Also, you're not using the addrcycles info provided by the the address instruction and instead
> deduce it based on the opcode, which is wrong.
> To make it clearer, I'd like to avoid those nfc_op.cmds[0] == NAND_OPCODE tests,
> because it's exactly the kind of things we were trying to get rid off by introducing the -
> >exec_op() interface.
Ok. I understand, I will remove hardcoding the commands in the driver.
And I will change the driver to read addrcycles info from address instruction.

Thanks,
Naga Sureshkumar Relli
> 
> > +	anfc_prepare_cmd(nfc, nfc_op.cmds[0], 0, dma_mode, write_size,
> > +			 addrcycles);
> > +	anfc_setpagecoladdr(nfc, nfc_op.row, nfc_op.col);
> > +
> > +	if (!nfc_op.data_instr)
> > +		return 0;
> > +
> > +	len = nand_subop_get_data_len(subop, op_id);
> > +	anfc_rw_pio_op(mtd, nfc->buf, roundup(len, 4), 1, nfc->prog, 1, 0);
> > +	memcpy(instr->ctx.data.buf.in,  nfc->buf, len);
> > +
> > +	return 0;
> > +}