[PATCH 6/6] mtd: spi-nand: Support common SPI NAND devices

[Qi Wang 王起 (qiwang)]

Hi Ezequiel,

> +static struct nand_ecclayout ecc_layout_mt29f = {
> +	.eccbytes = 32,
> +	.eccpos = {
> +		8, 9, 10, 11, 12, 13, 14, 15,
> +		24, 25, 26, 27, 28, 29, 30, 31,
> +		40, 41, 42, 43, 44, 45, 46, 47,
> +		56, 57, 58, 59, 60, 61, 62, 63,
> +	 },

Seems "OOB free" variable is missed. As below:

.oobfree = {
{ .offset = 2, .length = 6 },
{ .offset = 16, .length = 8 },
{ .offset = 32, .length = 8 },
{ .offset = 48, .length = 8 },
},


> +static int spi_nand_send_command(struct spi_device *spi, int command,
> +				 struct spi_nand_device_cmd *cmd) {
> +	struct spi_message message;
> +	struct spi_transfer x[4];
> +
> +	spi_message_init(&message);
> +	memset(x, 0, sizeof(x));
> +
> +	/* Command */
> +	cmd->cmd = command;
> +	x[0].len = 1;
> +	x[0].tx_buf = &cmd->cmd;
> +	spi_message_add_tail(&x[0], &message);
> +
> +	/* Address */
> +	if (cmd->n_addr) {
> +		x[1].len = cmd->n_addr;
> +		x[1].tx_buf = cmd->addr;
> +		spi_message_add_tail(&x[1], &message);
> +	}
> +
> +	/* Data to be transmitted */
> +	if (cmd->n_tx) {
> +		x[3].len = cmd->n_tx;
> +		x[3].tx_buf = cmd->tx_buf;
> +		spi_message_add_tail(&x[3], &message);
> +	}
> +
> +	/* Data to be received */
> +	if (cmd->n_rx) {
> +		x[3].len = cmd->n_rx;
> +		x[3].rx_buf = cmd->rx_buf;
> +		spi_message_add_tail(&x[3], &message);
> +	}

Only x[3] is used in above code, I suggest to separate transfer and received 
For x[2] and x[3], in case some command need to send dummy byte before received any data.

> +static int spi_nand_device_block_erase(struct spi_nand *snand,
> unsigned
> +int page_addr) {
> +	struct spi_nand_device *snand_dev = snand->priv;
> +	struct spi_nand_device_cmd *cmd = &snand_dev->cmd;
> +
> +	memset(cmd, 0, sizeof(struct spi_nand_device_cmd));
> +	cmd->n_addr = 3;
> +	cmd->addr[0] = 0;

Page address may beyond 16 bit in large density product. 
So I don't think addr[0] can be forced to be set 0


> +static int spi_nand_mt29f_read_id(struct spi_nand *snand, u8 *buf) {
> +	struct spi_nand_device *snand_dev = snand->priv;
> +	struct spi_nand_device_cmd *cmd = &snand_dev->cmd;
> +
> +	memset(cmd, 0, sizeof(struct spi_nand_device_cmd));
> +	cmd->n_rx = SPI_NAND_MT29F_READID_LEN;
> +	cmd->rx_buf = buf;
> +

Micron SPI NAND need 1 more dummy byte before received ID data.
Code for mt29f_read_id should be like this:

static int spi_nand_mt29f_read_id(struct spi_nand *snand, u8 *buf) {
	struct spi_nand_device *snand_dev = snand->priv;
	struct spi_nand_device_cmd *cmd = &snand_dev->cmd;
	u8 dummy = 0;
	memset(cmd, 0, sizeof(struct spi_nand_device_cmd));
"
	cmd->n_tx = 1;
	cmd->tx_buf = &dummy;
"
	cmd->n_rx = SPI_NAND_MT29F_READID_LEN;
	cmd->rx_buf = buf;

Thanks
Qi Wang