linux-kernel - Re: [PATCH v6 2/2] mtd: rawnand: Add NAND controller support on Intel LGM SoC

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Date:   Thu, 14 May 2020 09:02:17 +0800
From:   "Ramuthevar, Vadivel MuruganX" 
        <vadivel.muruganx.ramuthevar@...ux.intel.com>
To:     Andy Shevchenko <andriy.shevchenko@...el.com>
Cc:     linux-kernel@...r.kernel.org, linux-mtd@...ts.infradead.org,
        devicetree@...r.kernel.org, miquel.raynal@...tlin.com,
        richard@....at, vigneshr@...com, arnd@...db.de,
        brendanhiggins@...gle.com, tglx@...utronix.de,
        boris.brezillon@...labora.com, anders.roxell@...aro.org,
        masonccyang@...c.com.tw, robh+dt@...nel.org,
        linux-mips@...r.kernel.org, hauke.mehrtens@...el.com,
        qi-ming.wu@...el.com, cheol.yong.kim@...el.com
Subject: Re: [PATCH v6 2/2] mtd: rawnand: Add NAND controller support on Intel
 LGM SoC

Hi Andy,
On 13/5/2020 11:34 pm, Andy Shevchenko wrote:
> On Wed, May 13, 2020 at 06:46:15PM +0800, Ramuthevar,Vadivel MuruganX wrote:
>> From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@...ux.intel.com>
>>
>> This patch adds the new IP of Nand Flash Controller(NFC) support
>> on Intel's Lightning Mountain(LGM) SoC.
>>
>> DMA is used for burst data transfer operation, also DMA HW supports
>> aligned 32bit memory address and aligned data access by default.
>> DMA burst of 8 supported. Data register used to support the read/write
>> operation from/to device.
>>
>> NAND controller driver implements ->exec_op() to replace legacy hooks,
>> these specific call-back method to execute NAND operations.
> 
> ...
> 
>> +static int ebu_nand_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct ebu_nand_controller *ebu_host;
>> +	struct nand_chip *nand;
>> +	struct mtd_info *mtd;
>> +	struct resource *res;
>> +	char *resname;
>> +	int ret, i;
>> +	u32 reg;
>> +
>> +	ebu_host = devm_kzalloc(dev, sizeof(*ebu_host), GFP_KERNEL);
>> +	if (!ebu_host)
>> +		return -ENOMEM;
>> +
>> +	ebu_host->dev = dev;
>> +	nand_controller_init(&ebu_host->controller);
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ebunand");
>> +	ebu_host->ebu = devm_ioremap_resource(&pdev->dev, res);
> 
> devm_platform_ioremap_resource_byname
> 
>> +	if (IS_ERR(ebu_host->ebu))
>> +		return PTR_ERR(ebu_host->ebu);
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "hsnand");
>> +	ebu_host->hsnand = devm_ioremap_resource(&pdev->dev, res);
> 
> devm_platform_ioremap_resource_byname
Thanks for the review comments
As Boris suggested , split into 2 API's.

> 
>> +	if (IS_ERR(ebu_host->hsnand))
>> +		return PTR_ERR(ebu_host->hsnand);
>> +
>> +	ret = device_property_read_u32(dev, "nand,cs", &reg);
>> +	if (ret) {
>> +		dev_err(dev, "failed to get chip select: %d\n", ret);
>> +		return ret;
>> +	}
>> +	ebu_host->cs_num = reg;
>> +
>> +	for (i = 0; i < MAX_CS; i++) {
>> +		resname = devm_kasprintf(dev, GFP_KERNEL, "nand_cs%d", i);
>> +		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>> +						   resname);
> 
> if res is NULL?
Noted.
> 
>> +		ebu_host->cs[i].chipaddr = devm_ioremap_resource(dev, res);
>> +		ebu_host->cs[i].nand_pa = res->start;
>> +			if (IS_ERR(ebu_host->cs[i].chipaddr))
>> +				return PTR_ERR(ebu_host->cs[i].chipaddr);
> 
> Something happened with ordering / indentation along these lines...
Noted.
> 
>> +	}
>> +
> 
>> +	for (i = 0; i < MAX_CS; i++) {
>> +		resname = devm_kasprintf(dev, GFP_KERNEL, "addr_sel%d", i);
>> +		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>> +						   resname);
> 
> if res is NULL?
Noted.

Regards
Vadivel
> 
>> +		ebu_host->cs[i].addr_sel = res->start;
>> +		writel(ebu_host->cs[i].addr_sel | EBU_ADDR_MASK(5) |
>> +		       EBU_ADDR_SEL_REGEN, ebu_host->ebu + EBU_ADDR_SEL(i));
>> +	}
> 
>> +	return ret;
>> +}
> 
> ...
> 
>> +static int ebu_nand_remove(struct platform_device *pdev)
>> +{
>> +	struct ebu_nand_controller *ebu_host = platform_get_drvdata(pdev);
>> +
> 
>> +	if (ebu_host) {
> 
> How it can be NULL here?
> 
>> +		mtd_device_unregister(nand_to_mtd(&ebu_host->chip));
>> +		nand_cleanup(&ebu_host->chip);
>> +		ebu_nand_disable(&ebu_host->chip);
>> +
>> +		if (ebu_host->dma_rx || ebu_host->dma_tx)
>> +			ebu_dma_cleanup(ebu_host);
>> +
>> +		clk_disable_unprepare(ebu_host->clk);
>> +	}
>> +
>> +	return 0;
>> +}
> 
>