Gregory,
2016-11-29 11:19 GMT+01:00 Gregory CLEMENT <gregory.clem...@free-electrons.com>:
> Hi Marcin,
>
> On mar., nov. 29 2016, Marcin Wojtas <m...@semihalf.com> wrote:
>
>> Hi Gregory,
>>
>> Another remark below, sorry for noise.
>>
>> 2016-11-29 10:37 GMT+01:00 Gregory CLEMENT
>> <gregory.clem...@free-electrons.com>:
>>> Until now the virtual address of the received buffer were stored in the
>>> cookie field of the rx descriptor. However, this field is 32-bits only
>>> which prevents to use the driver on a 64-bits architecture.
>>>
>>> With this patch the virtual address is stored in an array not shared with
>>> the hardware (no more need to use the DMA API). Thanks to this, it is
>>> possible to use cache contrary to the access of the rx descriptor member.
>>>
>>> The change is done in the swbm path only because the hwbm uses the cookie
>>> field, this also means that currently the hwbm is not usable in 64-bits.
>>>
>>> Signed-off-by: Gregory CLEMENT <gregory.clem...@free-electrons.com>
>>> ---
>>> drivers/net/ethernet/marvell/mvneta.c | 93 ++++++++++++++++++++++++----
>>> 1 file changed, 81 insertions(+), 12 deletions(-)
>>>
>>> diff --git a/drivers/net/ethernet/marvell/mvneta.c
>>> b/drivers/net/ethernet/marvell/mvneta.c
>>> index 1b84f746d748..32b142d0e44e 100644
>>> --- a/drivers/net/ethernet/marvell/mvneta.c
>>> +++ b/drivers/net/ethernet/marvell/mvneta.c
>>> @@ -561,6 +561,9 @@ struct mvneta_rx_queue {
>>> u32 pkts_coal;
>>> u32 time_coal;
>>>
>>> + /* Virtual address of the RX buffer */
>>> + void **buf_virt_addr;
>>> +
>>> /* Virtual address of the RX DMA descriptors array */
>>> struct mvneta_rx_desc *descs;
>>>
>>> @@ -1573,10 +1576,14 @@ static void mvneta_tx_done_pkts_coal_set(struct
>>> mvneta_port *pp,
>>>
>>> /* Handle rx descriptor fill by setting buf_cookie and buf_phys_addr */
>>> static void mvneta_rx_desc_fill(struct mvneta_rx_desc *rx_desc,
>>> - u32 phys_addr, u32 cookie)
>>> + u32 phys_addr, void *virt_addr,
>>> + struct mvneta_rx_queue *rxq)
>>> {
>>> - rx_desc->buf_cookie = cookie;
>>> + int i;
>>> +
>>> rx_desc->buf_phys_addr = phys_addr;
>>> + i = rx_desc - rxq->descs;
>>> + rxq->buf_virt_addr[i] = virt_addr;
>>> }
>>>
>>> /* Decrement sent descriptors counter */
>>> @@ -1781,7 +1788,8 @@ EXPORT_SYMBOL_GPL(mvneta_frag_free);
>>>
>>> /* Refill processing for SW buffer management */
>>> static int mvneta_rx_refill(struct mvneta_port *pp,
>>> - struct mvneta_rx_desc *rx_desc)
>>> + struct mvneta_rx_desc *rx_desc,
>>> + struct mvneta_rx_queue *rxq)
>>>
>>> {
>>> dma_addr_t phys_addr;
>>> @@ -1799,7 +1807,7 @@ static int mvneta_rx_refill(struct mvneta_port *pp,
>>> return -ENOMEM;
>>> }
>>>
>>> - mvneta_rx_desc_fill(rx_desc, phys_addr, (u32)data);
>>> + mvneta_rx_desc_fill(rx_desc, phys_addr, data, rxq);
>>> return 0;
>>> }
>>>
>>> @@ -1861,7 +1869,12 @@ static void mvneta_rxq_drop_pkts(struct mvneta_port
>>> *pp,
>>>
>>> for (i = 0; i < rxq->size; i++) {
>>> struct mvneta_rx_desc *rx_desc = rxq->descs + i;
>>> - void *data = (void *)rx_desc->buf_cookie;
>>> + void *data;
>>> +
>>> + if (!pp->bm_priv)
>>> + data = rxq->buf_virt_addr[i];
>>> + else
>>> + data = (void *)(uintptr_t)rx_desc->buf_cookie;
>>
>> Dropping packets for HWBM (in fact returning dropped buffers to the
>> pool) is done a couple of lines above. This point will never be
>
> indeed I changed the code at every place the buf_cookie was used and
> missed the fact that for HWBM this code was never reached.
>
>> reached with HWBM enabled (and it's also incorrect).
>
> What is incorrect?
>
Possible dma_unmapping + mvneta_frag_free for buffers in HWBM, when
dropping packets.
Thanks,
Marcin
