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

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

[Maxim Kochetkov]

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 <fido_max@inbox.ru>
Reviewed-by: Robert Hancock <robert.hancock@calian.com>
---
 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

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

[Pandey, Radhey Shyam]

> -----Original Message-----
> From: Maxim Kochetkov <fido_max@inbox.ru>
> Sent: Friday, June 23, 2023 12:22 AM
> To: netdev@vger.kernel.org
> Cc: Maxim Kochetkov <fido_max@inbox.ru>; Robert Hancock
> <robert.hancock@calian.com>; Pandey, Radhey Shyam
> <radhey.shyam.pandey@amd.com>; David S. Miller
> <davem@davemloft.net>; Eric Dumazet <edumazet@google.com>; Jakub
> Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; Simek,
> Michal <michal.simek@amd.com>; Andre Przywara
> <andre.przywara@arm.com>; linux-arm-kernel@lists.infradead.org; linux-
> kernel@vger.kernel.org
> 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 <fido_max@inbox.ru>
> Reviewed-by: Robert Hancock <robert.hancock@calian.com>

Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Thanks!
> ---
>  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

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

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

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!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html