On Sun, Aug 20, 2023 at 09:15:06PM +0200, Andrew Lunn wrote: > On Wed, Aug 16, 2023 at 11:29:19PM +0800, Jisheng Zhang wrote: > > The XGMAC_HWFEAT_GMIISEL bit also indicates whether support 10/100Mbps > > or not. > > The commit message fails to explain the 'Why?' question. GMII does > normally imply 10/100/1000, so i would expect dma_cap->mbps_1000 also > implies 10/100/1000? So why also set dma_cap->mbps_10_100? > > Maybe a better change would be to modify: > > seq_printf(seq, "\t1000 Mbps: %s\n", > (priv->dma_cap.mbps_1000) ? "Y" : "N"); > > to actually say 10/100/1000 Mbps? It does not appear this is used for > anything other than debugfs? Indeed, it also looks to me like mbps_1000 and mbps_10_100 are only used to print things in the debugfs file, and do not have any effect on the driver. Moreover: drivers/net/ethernet/stmicro/stmmac/dwmac4.h:#define GMAC_HW_FEAT_GMIISEL BIT(1) drivers/net/ethernet/stmicro/stmmac/common.h:#define DMA_HW_FEAT_GMIISEL 0x00000002 /* 1000 Mbps Support */ drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h:#define XGMAC_HWFEAT_GMIISEL BIT(1) Seems to be all the same bit, and: drivers/net/ethernet/stmicro/stmmac/dwmac4.h:#define GMAC_HW_FEAT_MIISEL BIT(0) drivers/net/ethernet/stmicro/stmmac/common.h:#define DMA_HW_FEAT_MIISEL 0x00000001 /* 10/100 Mbps Support */ So, if everyone defines the first few bits of the hw_cap identically, is there any point to decoding this separately in each driver? Couldn't the debugfs "show" function just parse the hw_cap directly? Wouldn't it make more sense to print MII / GMII rather than 10/100 and 1000 ? It does bring up one last question though: if the driver makes no use of these hw_cap bits, then is there any point in printing them in the debugfs file? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
