From: Jakub Kicinski <kuba@kernel.org>
To: Yao Zi <ziyao@disroot.org>
Cc: Drew Fustini <fustini@kernel.org>, Guo Ren <guoren@kernel.org>,
Fu Wei <wefu@redhat.com>, Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
Emil Renner Berthing <emil.renner.berthing@canonical.com>,
Jisheng Zhang <jszhang@kernel.org>,
nux-riscv@lists.infradead.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] net: stmmac: thead: Enable TX clock before MAC initialization
Date: Tue, 5 Aug 2025 17:38:25 -0700 [thread overview]
Message-ID: <20250805173825.0f70f9cd@kernel.org> (raw)
In-Reply-To: <20250801094507.54011-1-ziyao@disroot.org>
On Fri, 1 Aug 2025 09:45:07 +0000 Yao Zi wrote:
> The clk_tx_i clock must be supplied to the MAC for successful
> initialization. On TH1520 SoC, the clock is provided by an internal
> divider configured through GMAC_PLLCLK_DIV register when using RGMII
> interface. However, currently we don't setup the divider before
> initialization of the MAC, resulting in DMA reset failures if the
> bootloader/firmware doesn't enable the divider,
>
> [ 7.839601] thead-dwmac ffe7060000.ethernet eth0: Register MEM_TYPE_PAGE_POOL RxQ-0
> [ 7.938338] thead-dwmac ffe7060000.ethernet eth0: PHY [stmmac-0:02] driver [RTL8211F Gigabit Ethernet] (irq=POLL)
> [ 8.160746] thead-dwmac ffe7060000.ethernet eth0: Failed to reset the dma
> [ 8.170118] thead-dwmac ffe7060000.ethernet eth0: stmmac_hw_setup: DMA engine initialization failed
> [ 8.179384] thead-dwmac ffe7060000.ethernet eth0: __stmmac_open: Hw setup failed
>
> Let's simply write GMAC_PLLCLK_DIV_EN to GMAC_PLLCLK_DIV to enable the
> divider before MAC initialization. The rate doesn't matter, which we
> could reclock properly according to the link speed later after link is
> up.
All the possible DIV values are valid?
I think it's safer to set the DIV to some well known constant,
just to be on the safe side.
next prev parent reply other threads:[~2025-08-06 0:38 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-01 9:45 [PATCH net] net: stmmac: thead: Enable TX clock before MAC initialization Yao Zi
2025-08-04 0:06 ` Drew Fustini
2025-08-06 0:38 ` Jakub Kicinski [this message]
2025-08-06 3:16 ` Yao Zi
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