[PATCH v2 1/1] net: axienet: Move reset before DMA detection

From: Maxim Kochetkov
Date: Thu Jun 22 2023 - 13:52:24 EST


DMA detection will fail if axinet was started before (by boot loader,
boot ROM, etc). In this state axinet 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
(axinet 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 axinet reset before DMA detection.

Fixes: 04cc2da39698 ("net: axienet: reset core on initialization prior to MDIO access")
Signed-off-by: Maxim Kochetkov <fido_max@xxxxxxxx>
---
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