On Thu, 4 Feb 2021 19:21:42 +0800 Joakim Zhang wrote:
> Driver uses dma_alloc_coherent to allocate dma memory for descriptors,
> dma_alloc_coherent will return both the virtual address and physical
> address. AFAIK, virt_to_phys could not convert virtual address to
> physical address, for which memory is allocated by dma_alloc_coherent.
>
> Signed-off-by: Joakim Zhang <qiangqing.zh...@nxp.com>
What does this patch fix? Theoretically incorrect value in a debug dump
or are you actually observing incorrect behavior?
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
> b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
> index c6540b003b43..6f951adc5f90 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
> @@ -402,7 +402,8 @@ static void dwmac4_rd_set_tx_ic(struct dma_desc *p)
> p->des2 |= cpu_to_le32(TDES2_INTERRUPT_ON_COMPLETION);
> }
>
> -static void dwmac4_display_ring(void *head, unsigned int size, bool rx)
> +static void dwmac4_display_ring(void *head, unsigned int size, bool rx,
> + dma_addr_t dma_rx_phy, unsigned int desc_size)
> {
> struct dma_desc *p = (struct dma_desc *)head;
> int i;
> @@ -410,8 +411,8 @@ static void dwmac4_display_ring(void *head, unsigned int
> size, bool rx)
> pr_info("%s descriptor ring:\n", rx ? "RX" : "TX");
>
> for (i = 0; i < size; i++) {
> - pr_info("%03d [0x%x]: 0x%x 0x%x 0x%x 0x%x\n",
> - i, (unsigned int)virt_to_phys(p),
> + pr_info("%03d [0x%llx]: 0x%x 0x%x 0x%x 0x%x\n",
> + i, (unsigned long long)(dma_rx_phy + i * desc_size),
> le32_to_cpu(p->des0), le32_to_cpu(p->des1),
> le32_to_cpu(p->des2), le32_to_cpu(p->des3));
> p++;
Why do you pass the desc_size in? The virt memory pointer is incremented
by sizeof(*p) surely
dma_addr + i * sizeof(*p)
would work correctly? Also please use the correct print format for
dma_addr_t, you shouldn't have to cast.
