On Mon, Jan 04, 2021 at 07:56:11PM +0200, Lauri Kasanen wrote:
> +static blk_status_t get_seg(struct request *req)
> +{
> + u32 bstart = blk_rq_pos(req) * 512;
> + u32 len = blk_rq_cur_bytes(req);
> + void *dst = bio_data(req->bio);
> +
> + if (bstart + len > size)
> + return BLK_STS_IOERR;
> +
> + bstart += start;
> +
> + while (len) {
> + const u32 curlen = len < BUFSIZE ? len : BUFSIZE;
> +
> + dma_cache_inv((unsigned long) buf, curlen);
> +
> + n64cart_wait_dma();
> +
> + barrier();
> + n64cart_write_reg(PI_DRAM_REG, dma_addr);
> + barrier();
> + n64cart_write_reg(PI_CART_REG, (bstart | 0x10000000) & 0x1FFFFFFF);
> + barrier();
> + n64cart_write_reg(PI_WRITE_REG, curlen - 1);
> + barrier();
> +
> + n64cart_wait_dma();
> +
> + memcpy(dst, buf, curlen);
Is there a reason for using a bounce buffer rather than reading directly
into the destination?
