diff mbox series

[netdev] net: stmmac: dwmac-rk: Provide FIFO sizes for DWMAC 1000

Message ID 20250204161359.3335241-1-wens@kernel.org (mailing list archive)
State New
Headers show
Series [netdev] net: stmmac: dwmac-rk: Provide FIFO sizes for DWMAC 1000 | expand

Commit Message

Chen-Yu Tsai Feb. 4, 2025, 4:13 p.m. UTC
From: Chen-Yu Tsai <wens@csie.org>

The DWMAC 1000 DMA capabilities register does not provide actual
FIFO sizes, nor does the driver really care. If they are not
provided via some other means, the driver will work fine, only
disallowing changing the MTU setting.

The recent commit 8865d22656b4 ("net: stmmac: Specify hardware
capability value when FIFO size isn't specified") changed this by
requiring the FIFO sizes to be provided, breaking devices that were
working just fine.

Provide the FIFO sizes through the driver's platform data, to not
only fix the breakage, but also enable MTU changes. The FIFO sizes
are confirmed to be the same across RK3288, RK3328, RK3399 and PX30,
based on their respective manuals. It is likely that Rockchip
synthesized their DWMAC 1000 with the same parameters on all their
chips that have it.

Fixes: eaf4fac47807 ("net: stmmac: Do not accept invalid MTU values")
Fixes: 8865d22656b4 ("net: stmmac: Specify hardware capability value when FIFO size isn't specified")
Cc: <stable@vger.kernel.org>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
The reason for stable inclusion is not to fix the device breakage
(which only broke in v6.14-rc1), but to provide the values so that MTU
changes can work in older kernels.

Since a fix for stmmac in general has already been sent [1] and a revert
was also proposed [2], I'll refrain from sending mine.

[1] https://lore.kernel.org/all/20250203093419.25804-1-steven.price@arm.com/
[2] https://lore.kernel.org/all/Z6Clkh44QgdNJu_O@shell.armlinux.org.uk/

 drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Andrew Lunn Feb. 4, 2025, 7:45 p.m. UTC | #1
On Wed, Feb 05, 2025 at 12:13:59AM +0800, Chen-Yu Tsai wrote:
> From: Chen-Yu Tsai <wens@csie.org>
> 
> The DWMAC 1000 DMA capabilities register does not provide actual
> FIFO sizes, nor does the driver really care. If they are not
> provided via some other means, the driver will work fine, only
> disallowing changing the MTU setting.
> 
> The recent commit 8865d22656b4 ("net: stmmac: Specify hardware
> capability value when FIFO size isn't specified") changed this by
> requiring the FIFO sizes to be provided, breaking devices that were
> working just fine.
> 
> Provide the FIFO sizes through the driver's platform data, to not
> only fix the breakage, but also enable MTU changes. The FIFO sizes
> are confirmed to be the same across RK3288, RK3328, RK3399 and PX30,
> based on their respective manuals. It is likely that Rockchip
> synthesized their DWMAC 1000 with the same parameters on all their
> chips that have it.
> 
> Fixes: eaf4fac47807 ("net: stmmac: Do not accept invalid MTU values")
> Fixes: 8865d22656b4 ("net: stmmac: Specify hardware capability value when FIFO size isn't specified")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
> The reason for stable inclusion is not to fix the device breakage
> (which only broke in v6.14-rc1), but to provide the values so that MTU
> changes can work in older kernels.

Allowing the MTU to be changed is probably classed as a new feature,
not bug fix.

I _think_ this also allows flow control, which again is a new feature.

Please submit to net-next.

	Andrew
Jakub Kicinski Feb. 4, 2025, 9:43 p.m. UTC | #2
On Wed,  5 Feb 2025 00:13:59 +0800 Chen-Yu Tsai wrote:
> Since a fix for stmmac in general has already been sent [1] and a revert
> was also proposed [2], I'll refrain from sending mine.

No, no, please do. You need to _submit_ the revert like a normal patch.
With all the usual details in the commit message.
Chen-Yu Tsai Feb. 5, 2025, 3:45 a.m. UTC | #3
On Wed, Feb 5, 2025 at 5:43 AM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Wed,  5 Feb 2025 00:13:59 +0800 Chen-Yu Tsai wrote:
> > Since a fix for stmmac in general has already been sent [1] and a revert
> > was also proposed [2], I'll refrain from sending mine.
>
> No, no, please do. You need to _submit_ the revert like a normal patch.
> With all the usual details in the commit message.

Mine isn't a revert, but simply downgrading the error to a warning.
So... yet another workaround approach.
diff mbox series

Patch

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
index a4dc89e23a68..71a4c4967467 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
@@ -1966,8 +1966,11 @@  static int rk_gmac_probe(struct platform_device *pdev)
 	/* If the stmmac is not already selected as gmac4,
 	 * then make sure we fallback to gmac.
 	 */
-	if (!plat_dat->has_gmac4)
+	if (!plat_dat->has_gmac4) {
 		plat_dat->has_gmac = true;
+		plat_dat->rx_fifo_size = 4096;
+		plat_dat->tx_fifo_size = 2048;
+	}
 	plat_dat->fix_mac_speed = rk_fix_speed;
 
 	plat_dat->bsp_priv = rk_gmac_setup(pdev, plat_dat, data);