Re: [PATCH v3 3/8] nand: spi: add basic blocks for infrastructure

Peter Pan
2017-03-20T04:56:06Z

Hi Boris,

On Fri, Mar 17, 2017 at 9:38 PM, Boris Brezillon
<boris.brezillon@free-electrons.com> wrote:
> On Thu, 16 Mar 2017 14:47:32 +0800
> Peter Pan <peterpandong@micron.com> wrote:
>
>
>> +
>> +/*
>> + * spinand_manufacturer_detect - detect SPI NAND device by each manufacturer
>> + * @chip: SPI NAND device structure
>> + * @raw_id: raw id buffer. raw id is read by spinand_read_id(), should be
>> + * decoded by manufacturers
>> + * @id: real id buffer. manufacturer's ->detect() should put real id in
>> + * this buffer.
>> + *
>> + * ->detect() should decode raw id and initialize device related part in
>> + * spinand_device structure if it is the right device.
>> + * ->detect() can not be NULL.
>> + */
>> +static int spinand_manufacturer_detect(struct spinand_device *chip,
>> + u8 *raw_id, u8 *id)
>> +{
>> + int i = 0;
>> +
>> + for (; spinand_manufacturers[i]->id != 0x0; i++) {
>> + if (spinand_manufacturers[i]->ops &&
>> + spinand_manufacturers[i]->ops->detect) {
>
> AFAIU, ->detect() is mandatory, otherwise you have no way to attach a
> NAND to this manufacturer which makes it useless.
> Am I missing something?
>
> If I'm right, you should assume that ->detect() is never NULL and
> complain loudly if it is.

You are totally right. Actually I said ->detect() cannot be NULL in
function header....
I will fix this in v4.

>
>> + if (spinand_manufacturers[i]->ops->detect(chip,
>> + raw_id, id))
>> + return 0;
>> + }
>> + }
>> +
>> + return -ENODEV;
>> +}
>> +
>> +/*
>> + * spinand_manufacturer_init - manufacturer initialization function.
>> + * @chip: SPI NAND device structure
>> + *
>> + * Manufacturer drivers should put all their specific initialization code in
>> + * their ->init() hook.
>> + */
>> +static int spinand_manufacturer_init(struct spinand_device *chip)
>> +{
>> + if (chip->manufacturer.manu->ops && chip->manufacturer.manu->ops->init)
>> + return chip->manufacturer.manu->ops->init(chip);
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * spinand_manufacturer_cleanup - manufacturer cleanup function.
>> + * @chip: SPI NAND device structure
>> + *
>> + * Manufacturer drivers should put all their specific cleanup code in their
>> + * ->cleanup() hook.
>> + */
>> +static void spinand_manufacturer_cleanup(struct spinand_device *chip)
>> +{
>> + /* Release manufacturer private data */
>> + if (chip->manufacturer.manu->ops &&
>> + chip->manufacturer.manu->ops->cleanup)
>> + return chip->manufacturer.manu->ops->cleanup(chip);
>> +}
>> +
>> +/*
>> + * spinand_fill_id - fill id in spinand_device structure.
>> + * @chip: SPI NAND device structure
>> + * @id: id buffer
>> + */
>> +static void spinand_fill_id(struct spinand_device *chip, u8 *id)
>> +{
>> + memcpy(chip->id.data, id, SPINAND_MAX_ID_LEN);
>> + chip->id.len = SPINAND_MAX_ID_LEN;
>> +}
>> +
>> +/*
>> + * spinand_get_mfr_id - get device's manufacturer ID.
>> + * @chip: SPI NAND device structure
>> + */
>> +static u8 spinand_get_mfr_id(struct spinand_device *chip)
>> +{
>> + return chip->id.data[SPINAND_MFR_ID];
>> +}
>> +
>> +/*
>> + * spinand_get_dev_id - get device's device ID.
>> + * @chip: SPI NAND device structure
>> + */
>> +static u8 spinand_get_dev_id(struct spinand_device *chip)
>> +{
>> + return chip->id.data[SPINAND_DEV_ID];
>> +}
>
> As said below, I'm not sure we need to identify the manufacturer and
> device ID bytes if we go for the raw-id approach.
>
>> +
>> +/*
>> + * spinand_set_manufacturer_ops - set manufacture ops in spinand_device
>> + * structure.
>> + * @chip: SPI NAND device structure
>> + * @mfr_id: device's manufacturer ID
>> + */
>> +static void spinand_set_manufacturer_ops(struct spinand_device *chip,
>> + u8 mfr_id)
>> +{
>> + int i = 0;
>> +
>> + for (; spinand_manufacturers[i]->id != 0x0; i++) {
>> + if (spinand_manufacturers[i]->id == mfr_id)
>> + break;
>> + }
>> +
>> + chip->manufacturer.manu = spinand_manufacturers[i];
>
> Clearly something that should be done in spinand_manufacturer_detect()
> when the ->detect() method returns true.

Yes. Fix this in v4.

>
>> +}
>> +
>> +/*
>> + * spinand_detect - [SPI NAND Interface] detect the SPI NAND device
>> + * @chip: SPI NAND device structure
>> + */
>> +int spinand_detect(struct spinand_device *chip)
>> +{
>> + struct nand_device *nand = &chip->base;
>> + u8 raw_id[SPINAND_MAX_ID_LEN] = {0};
>> + u8 id[SPINAND_MAX_ID_LEN] = {0};
>> + int ret;
>> +
>> + spinand_reset(chip);
>> + spinand_read_id(chip, raw_id);
>
> Directly store the raw id in chip->id.data.
>
>> + ret = spinand_manufacturer_detect(chip, raw_id, id);
>
> Why do you need to differentiate raw and non-raw IDs. If we consider the
> ID to be the 4 first bytes without any dummy-cycles, then we'd better
> store this one in chip->id.data and let manufacturer code parse it.

Fix this in v4

>
>> + if (ret)
>> + return ret;
>> +
>> + spinand_fill_id(chip, id);
>> +
>> + pr_info("SPI NAND: %s is found.\n", chip->name);
>> + pr_info("Manufacturer ID: 0x%02x, Chip ID: 0x%02x\n",
>> + spinand_get_mfr_id(chip), spinand_get_dev_id(chip));
>
> Is this really important to print those raw IDs? How about printing the
> manufacturer name (which should be part of struct spinand_manufacturer)
> and the model name (a readable string that can be extracted from the
> device id during detect).

Fix this in v4

Thanks,
Peter Pan