2023-06-22 20:00:03

by Maxim Kochetkov

Subject: [PATCH v3 1/1] net: axienet: Move reset before DMA detection

DMA detection will fail if axienet was started before (by boot loader,
boot ROM, etc). In this state axienet will not start properly.
XAXIDMA_TX_CDESC_OFFSET + 4 register (MM2S_CURDESC_MSB) is used to detect
64 DMA capability here. But datasheet says: When DMACR.RS is 1
(axienet is in enabled state), CURDESC_PTR becomes Read Only (RO) and
is used to fetch the first descriptor. So iowrite32()/ioread32() trick
to this register to detect DMA will not work.
So move axienet reset before DMA detection.

Fixes: f735c40ed93c ("net: axienet: Autodetect 64-bit DMA capability")
Signed-off-by: Maxim Kochetkov <[email protected]>
Reviewed-by: Robert Hancock <[email protected]>
---
drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 3e310b55bce2..734822321e0a 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -2042,6 +2042,11 @@ static int axienet_probe(struct platform_device *pdev)
goto cleanup_clk;
}

+ /* Reset core now that clocks are enabled, prior to accessing MDIO */
+ ret = __axienet_device_reset(lp);
+ if (ret)
+ goto cleanup_clk;
+
/* Autodetect the need for 64-bit DMA pointers.
* When the IP is configured for a bus width bigger than 32 bits,
* writing the MSB registers is mandatory, even if they are all 0.
@@ -2096,11 +2101,6 @@ static int axienet_probe(struct platform_device *pdev)
lp->coalesce_count_tx = XAXIDMA_DFT_TX_THRESHOLD;
lp->coalesce_usec_tx = XAXIDMA_DFT_TX_USEC;

- /* Reset core now that clocks are enabled, prior to accessing MDIO */
- ret = __axienet_device_reset(lp);
- if (ret)
- goto cleanup_clk;
-
ret = axienet_mdio_setup(lp);
if (ret)
dev_warn(&pdev->dev,
--
2.40.1

2023-06-24 23:36:02

by patchwork-bot+netdevbpf

Subject: Re: [PATCH v3 1/1] net: axienet: Move reset before DMA detection

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <[email protected]>:

On Thu, 22 Jun 2023 21:51:30 +0300 you wrote:
> DMA detection will fail if axienet was started before (by boot loader,
> boot ROM, etc). In this state axienet will not start properly.
> XAXIDMA_TX_CDESC_OFFSET + 4 register (MM2S_CURDESC_MSB) is used to detect
> 64 DMA capability here. But datasheet says: When DMACR.RS is 1
> (axienet is in enabled state), CURDESC_PTR becomes Read Only (RO) and
> is used to fetch the first descriptor. So iowrite32()/ioread32() trick
> to this register to detect DMA will not work.
> So move axienet reset before DMA detection.
>
> [...]

Here is the summary with links:
- [v3,1/1] net: axienet: Move reset before DMA detection
https://git.kernel.org/netdev/net/c/f1bc9fc4a06d

You are awesome, thank you!
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