[PATCH v2 3/5] net: designware: eqos: add comment about external clock dependencies for the soft reset

Oleksij Rempel o.rempel at pengutronix.de
Sun Aug 13 22:32:27 PDT 2023


This part of code is not error proof and may fail depending on
implementation state of external HW. I hope this note help to find bugs
later.

Signed-off-by: Oleksij Rempel <o.rempel at pengutronix.de>
---
 drivers/net/designware_eqos.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/designware_eqos.c b/drivers/net/designware_eqos.c
index 6caf3a436f..4489725e87 100644
--- a/drivers/net/designware_eqos.c
+++ b/drivers/net/designware_eqos.c
@@ -427,6 +427,10 @@ static int eqos_start(struct eth_device *edev)
 	if (ret)
 		return ret;
 
+	/* In some cases where PHY or DSA switch is the clock provider for
+	 * EQOS, we need to probe and configure them before issuing software
+	 * reset here.
+	 */
 	setbits_le32(&eqos->dma_regs->mode, EQOS_DMA_MODE_SWR);
 
 	ret = readl_poll_timeout(&eqos->dma_regs->mode, mode_set,
-- 
2.39.2




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