Hi all,
I'll highly appreciated any of your comments.
On 2016/3/26 16:11, Jiancheng Xue wrote:
> Add hisilicon spi-nor flash controller driver
>
[...]
> +static int hisi_spi_nor_read(struct spi_nor *nor, loff_t from, size_t len,
> + size_t *retlen, u_char *read_buf)
> +{
> + struct hifmc_priv *priv = nor->priv;
> + struct hifmc_host *host = priv->host;
> + unsigned char *ptr = read_buf;
> + size_t actual_len;
> +
> + *retlen = 0;
> + while (len > 0) {
> + actual_len = (len >= HIFMC_DMA_MAX_LEN)
> + ? HIFMC_DMA_MAX_LEN : len;
> + hisi_spi_nor_dma_transfer(nor, from, host->dma_buffer,
> + actual_len, FMC_OP_READ);
> + memcpy(ptr, host->buffer, actual_len);
> + ptr += actual_len;
> + from += actual_len;
> + len -= actual_len;
> + *retlen += actual_len;
> + }
> +
> + return 0;
> +}
For easy understanding, the read function will be changed like below:
static int hisi_spi_nor_read(struct spi_nor *nor, loff_t from, size_t len,
size_t *retlen, u_char *read_buf)
{
struct hifmc_priv *priv = nor->priv;
struct hifmc_host *host = priv->host;
int i;
/* read all bytes in only one time */
if (len <= HIFMC_DMA_MAX_LEN) {
hisi_spi_nor_dma_transfer(nor, from, host->dma_buffer,
len, FMC_OP_READ);
memcpy(read_buf, host->buffer, len);
} else {
/* read HIFMC_DMA_MAX_LEN bytes at a time */
for (i = 0; i < len; i += HIFMC_DMA_MAX_LEN) {
hisi_spi_nor_dma_transfer(nor, from + i, host->dma_buffer,
HIFMC_DMA_MAX_LEN, FMC_OP_READ);
memcpy(read_buf + i, host->buffer, HIFMC_DMA_MAX_LEN);
}
/* read remaining bytes */
i -= HIFMC_DMA_MAX_LEN;
hisi_spi_nor_dma_transfer(nor, from + i, host->dma_buffer,
len - i, FMC_OP_READ);
memcpy(read_buf + i, host->buffer, len - i);
}
*retlen = len;
return 0;
}
> +static void hisi_spi_nor_write(struct spi_nor *nor, loff_t to,
> + size_t len, size_t *retlen, const u_char *write_buf)
> +{
> + struct hifmc_priv *priv = nor->priv;
> + struct hifmc_host *host = priv->host;
> + const unsigned char *ptr = write_buf;
> + size_t actual_len;
> +
> + *retlen = 0;
> + while (len > 0) {
> + if (to & HIFMC_DMA_MASK)
> + actual_len = (HIFMC_DMA_MAX_LEN - (to & HIFMC_DMA_MASK))
> + >= len ? len
> + : (HIFMC_DMA_MAX_LEN - (to & HIFMC_DMA_MASK));
> + else
> + actual_len = (len >= HIFMC_DMA_MAX_LEN)
> + ? HIFMC_DMA_MAX_LEN : len;
> + memcpy(host->buffer, ptr, actual_len);
> + hisi_spi_nor_dma_transfer(nor, to, host->dma_buffer, actual_len,
> + FMC_OP_WRITE);
> + to += actual_len;
> + ptr += actual_len;
> + len -= actual_len;
> + *retlen += actual_len;
> + }
> +}
> +
Because "len" passed from spi_nor_write is smaller than nor->page_size, and nor->page_size
is smaller than the length of host->dma_buffer. We can transfer "len" bytes data by
hisi_spi_nor_dma_transfer at one time. hisi_spi_nor_write can be simplified like below:
static void hisi_spi_nor_write(struct spi_nor *nor, loff_t to,
size_t len, size_t *retlen, const u_char *write_buf)
{
struct hifmc_priv *priv = nor->priv;
struct hifmc_host *host = priv->host;
/* len is smaller than dma buffer length*/
memcpy(host->buffer, write_buf, len);
hisi_spi_nor_dma_transfer(nor, to, host->dma_buffer, len,
FMC_OP_WRITE);
*retlen = len;
}
Regards,
Jiancheng
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