linux-kernel - RE: [LINUX PATCH v12 3/3] mtd: rawnand: arasan: Add support for Arasan NAND Flash Controller

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 4 Dec 2018 09:18:53 +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>,
        "nagasuresh12@...il.com" <nagasuresh12@...il.com>,
        "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "robh@...nel.org" <robh@...nel.org>
Subject: RE: [LINUX PATCH v12 3/3] mtd: rawnand: arasan: Add support for
 Arasan NAND Flash Controller

Hi Boris,

> -----Original Message-----
> From: Boris Brezillon [mailto:boris.brezillon@...tlin.com]
> Sent: Tuesday, November 20, 2018 9:55 PM
> 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>; nagasuresh12@...il.com; linux-mtd@...ts.infradead.org; linux-
> kernel@...r.kernel.org; robh@...nel.org
> Subject: Re: [LINUX PATCH v12 3/3] mtd: rawnand: arasan: Add support for Arasan
> NAND Flash Controller
> 
> On Fri, 9 Nov 2018 10:30:41 +0530
> Naga Sureshkumar Relli <naga.sureshkumar.relli@...inx.com> wrote:
> 
> > +static int anfc_setup_data_interface(struct nand_chip *chip, int csline,
> > +				     const struct nand_data_interface *conf) {
> > +	struct anfc_nand_controller *nfc = to_anfc(chip->controller);
> > +	struct anfc_nand_chip *achip = to_anfc_nand(chip);
> > +	int err;
> > +	const struct nand_sdr_timings *sdr;
> > +	u32 inftimeval;
> > +	bool change_sdr_clk = false;
> > +
> > +	if (csline == NAND_DATA_IFACE_CHECK_ONLY)
> > +		return 0;
> > +
> > +	/*
> > +	 * If the controller is already in the same mode as flash device
> > +	 * then no need to change the timing mode again.
> > +	 */
> > +	sdr = nand_get_sdr_timings(conf);
> > +	if (IS_ERR(sdr))
> > +		return PTR_ERR(sdr);
> > +
> > +	if (sdr->mode < 0)
> > +		return -ENOTSUPP;
> > +
> > +	inftimeval = sdr->mode & 7;
> > +	if (sdr->mode >= 2 && sdr->mode <= 5)
> > +		change_sdr_clk = true;
> > +	/*
> > +	 * SDR timing modes 2-5 will not work for the arasan nand when
> > +	 * freq > 90 MHz, so reduce the freq in SDR modes 2-5 to < 90Mhz
> 
> What's the freq for mode 0 and 1?
It is 100MHz in SDR mode 0 and 1.

> 
> > +	 */
> > +	if (change_sdr_clk) {
> > +		clk_disable_unprepare(nfc->clk_sys);
> > +		err = clk_set_rate(nfc->clk_sys, SDR_MODE_DEFLT_FREQ);
> 
> You should not change the clk rate here. It should be done when the chip is selected, so that,
> if you ever have 2 different chips connected to the same controller, you can adapt the rate
> when they are accessed.
Ok, got it. I will update.

> 
> > +		if (err) {
> > +			dev_err(nfc->dev, "Can't set the clock rate\n");
> > +			return err;
> > +		}
> > +		err = clk_prepare_enable(nfc->clk_sys);
> > +		if (err) {
> > +			dev_err(nfc->dev, "Unable to enable sys clock.\n");
> > +			clk_disable_unprepare(nfc->clk_sys);
> > +			return err;
> > +		}
> > +	}
> > +	achip->inftimeval = inftimeval;
> > +
> > +	return 0;
> > +}
> > +
> > +static int anfc_nand_attach_chip(struct nand_chip *chip) {
> > +	struct mtd_info *mtd = nand_to_mtd(chip);
> > +	struct anfc_nand_chip *achip = to_anfc_nand(chip);
> > +	u32 ret;
> > +
> > +	if (mtd->writesize <= SZ_512)
> > +		achip->spare_caddr_cycles = 1;
> > +	else
> > +		achip->spare_caddr_cycles = 2;
> > +
> > +	chip->ecc.calc_buf = kmalloc(mtd->oobsize, GFP_KERNEL);
> > +	chip->ecc.code_buf = kmalloc(mtd->oobsize, GFP_KERNEL);
> 
> Those bufs are allocated but never freed (memleak). Also, are you sure you really need them.
These bufs are freed in nand_release(), which is calling from anfc_remove().

And chip->ecc.code_buf, is used in anfc_read_page_hwecc().
What we are doing here is, extract ECC code from OOB and place it in ecv.code_buf, and passing this info to nand_check_ecc_chunk(buf, chip->ecc.size, &ecc_code[i], eccbytes, NULL, 0,chip->ecc.strength).
i.e. just to store ECC code from OOB area.
 
And chip->ecc.calc_buf is no where used in the driver, I will remove it.

Thanks,
Naga Sureshkumar Relli.