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

[Nicolas Ferre <nicolas.ferre@microchip.com>]

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@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@raspberrypi.com>
>> Credits-to: Jonathan Bell <jonathan@raspberrypi.com>
>> Signed-off-by: Stanimir Varbanov <svarbanov@suse.de>
>> Reviewed-by: Andrew Lunn <andrew@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@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).

Best regards,
   Nicolas