[PATCH v2 1/5] net: cadence: macb: Set upper 32bits of DMA ring buffer

[Stanimir Varbanov]

On 8/26/25 12:14 PM, Nicolas Ferre wrote:
> On 26/08/2025 at 01:53, Jakub Kicinski wrote:
>> On Fri, 22 Aug 2025 12:34:36 +0300 Stanimir Varbanov wrote:
>>> In case of rx queue reset and 64bit capable hardware, set the upper
>>> 32bits of DMA ring buffer address.
>>>
>>> Cc: stable at vger.kernel.org # v4.6+
>>> Fixes: 9ba723b081a2 ("net: macb: remove BUG_ON() and reset the queue
>>> to handle RX errors")
>>> Credits-to: Phil Elwell <phil at raspberrypi.com>
>>> Credits-to: Jonathan Bell <jonathan at raspberrypi.com>
>>> Signed-off-by: Stanimir Varbanov <svarbanov at suse.de>
>>> Reviewed-by: Andrew Lunn <andrew at lunn.ch>
>>
>>> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/
>>> ethernet/cadence/macb_main.c
>>> index ce95fad8cedd..36717e7e5811 100644
>>> --- a/drivers/net/ethernet/cadence/macb_main.c
>>> +++ b/drivers/net/ethernet/cadence/macb_main.c
>>> @@ -1634,7 +1634,11 @@ static int macb_rx(struct macb_queue *queue,
>>> struct napi_struct *napi,
>>>                macb_writel(bp, NCR, ctrl & ~MACB_BIT(RE));
>>>
>>>                macb_init_rx_ring(queue);
>>> -             queue_writel(queue, RBQP, queue->rx_ring_dma);
>>> +             queue_writel(queue, RBQP, lower_32_bits(queue-
>>> >rx_ring_dma));
>>> +#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
>>> +             if (bp->hw_dma_cap & HW_DMA_CAP_64B)
>>> +                     macb_writel(bp, RBQPH, upper_32_bits(queue-
>>> >rx_ring_dma));
>>> +#endif
>>>
>>>                macb_writel(bp, NCR, ctrl | MACB_BIT(RE));
>>>
>>
>> Looks like a subset of Théo Lebrun's work:
>> https://lore.kernel.org/all/20250820-macb-fixes-
>> v4-0-23c399429164 at bootlin.com/
>> let's wait for his patches to get merged instead?
> 
> Yes, we can certainly wait. As RBOPH changes by Théo are key, they will
> probably remove the need for this fix altogether: but I count on you
> Stanimir to monitor that (as I don't have a 64 bit capable platform at
> hand).

Sure I will monitor those series. Unfortunately I also don't have MACB
64bit platform, I only have GEM.

regards,
~Stan