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Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:35002) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1pjJzb-0002oj-SP; Mon, 03 Apr 2023 14:13:03 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1pjJza-0004GU-TN; Mon, 03 Apr 2023 14:13:02 +0100 Date: Mon, 3 Apr 2023 14:13:02 +0100 From: "Russell King (Oracle)" To: Siddharth Vadapalli Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, rogerq@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, srk@ti.com Subject: Re: [PATCH net-next v2 1/3] net: ethernet: ti: am65-cpsw: Move mode specific config to mac_config() Message-ID: References: <20230403110106.983994-1-s-vadapalli@ti.com> <20230403110106.983994-2-s-vadapalli@ti.com> <3a62f5cf-ebba-1603-50a0-7a873973534d@ti.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <3a62f5cf-ebba-1603-50a0-7a873973534d@ti.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230403_061315_064771_58FEB59C X-CRM114-Status: GOOD ( 36.18 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Apr 03, 2023 at 06:31:52PM +0530, Siddharth Vadapalli wrote: > > > On 03-04-2023 16:38, Russell King (Oracle) wrote: > > On Mon, Apr 03, 2023 at 04:31:04PM +0530, Siddharth Vadapalli wrote: > >> Move the interface mode specific configuration to the mac_config() > >> callback am65_cpsw_nuss_mac_config(). > >> > >> Signed-off-by: Siddharth Vadapalli > >> --- > >> drivers/net/ethernet/ti/am65-cpsw-nuss.c | 10 +++++++--- > >> 1 file changed, 7 insertions(+), 3 deletions(-) > >> > >> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c > >> index d17757ecbf42..74e099828978 100644 > >> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c > >> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c > >> @@ -1504,12 +1504,17 @@ static void am65_cpsw_nuss_mac_config(struct phylink_config *config, unsigned in > >> phylink_config); > >> struct am65_cpsw_port *port = container_of(slave, struct am65_cpsw_port, slave); > >> struct am65_cpsw_common *common = port->common; > >> + u32 mac_control = 0; > >> > >> if (common->pdata.extra_modes & BIT(state->interface)) { > >> - if (state->interface == PHY_INTERFACE_MODE_SGMII) > >> + if (state->interface == PHY_INTERFACE_MODE_SGMII) { > >> + mac_control |= CPSW_SL_CTL_EXT_EN; > >> writel(ADVERTISE_SGMII, > >> port->sgmii_base + AM65_CPSW_SGMII_MR_ADV_ABILITY_REG); > >> + } > >> > >> + if (mac_control) > >> + cpsw_sl_ctl_set(port->slave.mac_sl, mac_control); > >> writel(AM65_CPSW_SGMII_CONTROL_MR_AN_ENABLE, > >> port->sgmii_base + AM65_CPSW_SGMII_CONTROL_REG); > >> } > >> @@ -1553,8 +1558,7 @@ static void am65_cpsw_nuss_mac_link_up(struct phylink_config *config, struct phy > >> > >> if (speed == SPEED_1000) > >> mac_control |= CPSW_SL_CTL_GIG; > >> - if (interface == PHY_INTERFACE_MODE_SGMII) > >> - mac_control |= CPSW_SL_CTL_EXT_EN; > >> + /* TODO: Verify whether in-band is necessary for 10 Mbps RGMII */ > >> if (speed == SPEED_10 && phy_interface_mode_is_rgmii(interface)) > >> /* Can be used with in band mode only */ > >> mac_control |= CPSW_SL_CTL_EXT_EN; > > > > I'm afraid I can see you haven't thought this patch through properly. > > > > am65_cpsw_nuss_mac_link_down() will call > > cpsw_sl_ctl_reset(port->slave.mac_sl); which has the effect of clearing > > to zero the entire MAC control register. This will clear > > CPSW_SL_CTL_EXT_EN that was set in am65_cpsw_nuss_mac_config() which is > > not what you want to be doing. > > > > Given that we have the 10Mbps issue with RGMII, I think what you want > > to be doing is: > > > > 1. Set CPSW_SL_CTL_EXT_EN in am65_cpsw_nuss_mac_config() if in SGMII > > mode, otherwise clear this bit. > > > > 2. Clear the mac_control register in am65_cpsw_nuss_mac_link_down() > > if in RMGII mode, otherwise preserve the state of > > CPSW_SL_CTL_EXT_EN but clear all other bits. > > > > 3. Set CPSW_SL_CTL_EXT_EN in am65_cpsw_nuss_mac_link_up() if in > > RGMII mode and 10Mbps. > > I plan to implement it as follows: > 1. Add a member "u32 mode_config" to "struct am65_cpsw_slave_data" in > "am65-cpsw-nuss.h". > 2. In am65_cpsw_nuss_mac_config(), store the value of mac_control in > "port->slave.mode_config". > 3. In am65_cpsw_nuss_mac_link_down(), after the reset via > cpsw_sl_ctl_reset(), execute: > cpsw_sl_ctl_set(port->slave.mac_sl, port->slave.mode_config) in order to > restore the configuration performed in am65_cpsw_nuss_mac_config(). > > Please let me know in case of any suggestions to implement it in a > better manner. Do you think this complexity is really worth it? Let's look at what's available: cpsw_sl_ctl_set() - sets bits in the mac control register cpsw_sl_ctl_clr() - clears bits in the mac control register cpsw_sl_ctl_reset() - sets the mac control register to zero So, in mac_config(), we can do: if (interface == SGMII) cpsw_sl_ctl_set(CPSW_SL_CTL_EXT_EN); else cpsw_sl_ctl_clr(CPSW_SL_CTL_EXT_EN); in mac_link_down(): u32 ctl; ctl = CPSW_SL_CTL_GMII_EN | CPSW_SL_CTL_GIG | CPSW_SL_CTL_IFCTL_A | CPSW_SL_CTL_FULLDUPLEX | CPSW_SL_CTL_RX_FLOW_EN | CPSW_SL_CTL_TX_FLOW_EN; if (phy_interface_mode_is_rgmii(interface)) ctl |= CPSW_SL_CTL_EXT_EN; cpsw_sl_ctl_clr(ctl); This ensures that we don't touch any bits in mac_link_down() which we aren't modifying in the corresponding mac_link_up() implementation. Q: do we really need to clear the mac control register on link down? If we don't, then we can do better, but we need an additional helper which allows read-modify-write of the mac control register using a mask value and a value of bits to set. Then we can have mac_link_up() setting and clearing the bits as necessary - but I would still keep the clearing of CPSW_SL_CTL_EXT_EN for RGMII modes in mac_link_down() for now. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel