Date:	Wed, 8 Jun 2016 22:48:30 -0700
From:	Tien Hock Loh <thloh@...era.com>
To:	Giuseppe CAVALLARO <peppe.cavallaro@...com>
CC:	<robh+dt@...nel.org>, <pawel.moll@....com>, <mark.rutland@....com>,
	<ijc+devicetree@...lion.org.uk>, <galak@...eaurora.org>,
	<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<netdev@...r.kernel.org>, <thloh85@...il.com>,
	<cnphoon@...era.com>, <thloh@...era.com>
Subject: Re: [PATCH v3 1/1] net: ethernet: Add TSE PCS support to
 dwmac-socfpga

Hi Peppe,

On Tue, 2016-06-07 at 10:30 +0200, Giuseppe CAVALLARO wrote:
> Hello
> 
> On 6/7/2016 5:01 AM, thloh@...era.com wrote:
> > From: Tien Hock Loh <thloh@...era.com>
> >
> > This adds support for TSE PCS that uses SGMII adapter when the phy-mode of
> > the dwmac is set to sgmii
> >
> > Signed-off-by: Tien Hock Loh <thloh@...era.com>
> >
> > ---
> > v2:
> > - Refactored the TSE PCS out from the dwmac-socfpga.c file
> > - Added binding documentation for TSE PCS sgmii adapter
> > v3:
> > - Added missing license header for new source files
> > - Updated tse_pcs.h include headers
> > - Standardize if statements
> > ---
> >  .../devicetree/bindings/net/socfpga-dwmac.txt      |   4 +
> >  drivers/net/ethernet/stmicro/stmmac/Makefile       |   2 +-
> >  .../net/ethernet/stmicro/stmmac/dwmac-socfpga.c    | 140 +++++++++--
> >  drivers/net/ethernet/stmicro/stmmac/tse_pcs.c      | 261 +++++++++++++++++++++
> >  drivers/net/ethernet/stmicro/stmmac/tse_pcs.h      |  36 +++
> >  5 files changed, 419 insertions(+), 24 deletions(-)
> >  create mode 100644 drivers/net/ethernet/stmicro/stmmac/tse_pcs.c
> >  create mode 100644 drivers/net/ethernet/stmicro/stmmac/tse_pcs.h
> 
> I just wonder if it could make sense to rename the
> tse_pcs.[hc] files or creating a sub-directory for altera devel.
> It seems that tse_pcs.[hc] are common files but this support
> is for Altera.
> Anyway, I let you decide and I also ask you to update the stmmac.txt
> file.

Yeah the PCS support for TSE is Altera. To avoid confusion, let's rename
them, would altr_tse_pcs.[hc] be good? I don't think creating a
sub-directory with only 2 files is necessary though.

I see that stmmac.txt is generic, and other vendor's PCS support
documents their specific uses in their own *-dwmac.txt (eg.
rockchip-dwmac.txt). Is this not the case?

> 
> > diff --git a/Documentation/devicetree/bindings/net/socfpga-dwmac.txt b/Documentation/devicetree/bindings/net/socfpga-dwmac.txt
> > index 3a9d679..2bc39f1 100644
> > --- a/Documentation/devicetree/bindings/net/socfpga-dwmac.txt
> > +++ b/Documentation/devicetree/bindings/net/socfpga-dwmac.txt
> > @@ -15,6 +15,8 @@ Required properties:
> >  Optional properties:
> >  altr,emac-splitter: Should be the phandle to the emac splitter soft IP node if
> >  		DWMAC controller is connected emac splitter.
> > +phy-mode: The phy mode the ethernet operates in
> > +altr,sgmii_to_sgmii_converter: phandle to the TSE SGMII converter
> >
> >  Example:
> >
> > @@ -28,4 +30,6 @@ gmac0: ethernet@...00000 {
> >  	mac-address = [00 00 00 00 00 00];/* Filled in by U-Boot */
> >  	clocks = <&emac_0_clk>;
> >  	clock-names = "stmmaceth";
> > +	phy-mode = "sgmii";
> > +	altr,gmii_to_sgmii_converter = <&sgmii_1_gmii_to_sgmii_converter_0>;
> >  };
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > index 73c2715..29c1dee 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> > +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > @@ -6,7 +6,7 @@ stmmac-objs:= stmmac_main.o stmmac_ethtool.o stmmac_mdio.o ring_mode.o	\
> >
> >  obj-$(CONFIG_STMMAC_PLATFORM) += stmmac-platform.o
> >  stmmac-platform-objs:= stmmac_platform.o dwmac-meson.o dwmac-sunxi.o	\
> > -		       dwmac-sti.o dwmac-socfpga.o dwmac-rk.o
> > +		       dwmac-sti.o dwmac-socfpga.o dwmac-rk.o tse_pcs.o
> >
> >  obj-$(CONFIG_STMMAC_PCI) += stmmac-pci.o
> >  stmmac-pci-objs:= stmmac_pci.o
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
> > index 3f9588e..88fba4e 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
> > @@ -27,6 +27,8 @@
> >  #include "stmmac.h"
> >  #include "stmmac_platform.h"
> >
> > +#include "tse_pcs.h"
> > +
> >  #define SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_GMII_MII 0x0
> >  #define SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_RGMII 0x1
> >  #define SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_RMII 0x2
> > @@ -47,48 +49,60 @@ struct socfpga_dwmac {
> >  	struct regmap *sys_mgr_base_addr;
> >  	struct reset_control *stmmac_rst;
> >  	void __iomem *splitter_base;
> > +	struct tse_pcs pcs;
> >  };
> >
> >  static void socfpga_dwmac_fix_mac_speed(void *priv, unsigned int speed)
> >  {
> >  	struct socfpga_dwmac *dwmac = (struct socfpga_dwmac *)priv;
> >  	void __iomem *splitter_base = dwmac->splitter_base;
> > +	void __iomem *tse_pcs_base = dwmac->pcs.tse_pcs_base;
> > +	void __iomem *sgmii_adapter_base = dwmac->pcs.sgmii_adapter_base;
> > +	struct device *dev = dwmac->dev;
> > +	struct net_device *ndev = dev_get_drvdata(dev);
> > +	struct phy_device *phy_dev = ndev->phydev;
> >  	u32 val;
> >
> > -	if (!splitter_base)
> > -		return;
> > -
> > -	val = readl(splitter_base + EMAC_SPLITTER_CTRL_REG);
> > -	val &= ~EMAC_SPLITTER_CTRL_SPEED_MASK;
> > -
> > -	switch (speed) {
> > -	case 1000:
> > -		val |= EMAC_SPLITTER_CTRL_SPEED_1000;
> > -		break;
> > -	case 100:
> > -		val |= EMAC_SPLITTER_CTRL_SPEED_100;
> > -		break;
> > -	case 10:
> > -		val |= EMAC_SPLITTER_CTRL_SPEED_10;
> > -		break;
> > -	default:
> > -		return;
> > +	if (splitter_base) {
> > +		val = readl(splitter_base + EMAC_SPLITTER_CTRL_REG);
> > +		val &= ~EMAC_SPLITTER_CTRL_SPEED_MASK;
> > +
> > +		switch (speed) {
> > +		case 1000:
> > +			val |= EMAC_SPLITTER_CTRL_SPEED_1000;
> > +			break;
> > +		case 100:
> > +			val |= EMAC_SPLITTER_CTRL_SPEED_100;
> > +			break;
> > +		case 10:
> > +			val |= EMAC_SPLITTER_CTRL_SPEED_10;
> > +			break;
> > +		default:
> > +			return;
> > +		}
> > +		writel(val, splitter_base + EMAC_SPLITTER_CTRL_REG);
> >  	}
> >
> > -	writel(val, splitter_base + EMAC_SPLITTER_CTRL_REG);
> > +	if ((tse_pcs_base) && (sgmii_adapter_base))
> > +		tse_pcs_fix_mac_speed(&dwmac->pcs, phy_dev, speed);
> >  }
> >
> > -static int socfpga_dwmac_parse_data(struct socfpga_dwmac *dwmac, struct device *dev)
> > +static int socfpga_dwmac_parse_data(struct socfpga_dwmac *dwmac,
> > +				    struct device *dev)
> >  {
> >  	struct device_node *np = dev->of_node;
> >  	struct regmap *sys_mgr_base_addr;
> >  	u32 reg_offset, reg_shift;
> > -	int ret;
> > -	struct device_node *np_splitter;
> > +	int ret, index;
> > +	struct device_node *np_splitter = NULL;
> > +	struct device_node *np_sgmii_adapter = NULL;
> > +
> >  	struct resource res_splitter;
> > +	struct resource res_tse_pcs;
> > +	struct resource res_sgmii_adapter;
> >
> >  	dwmac->stmmac_rst = devm_reset_control_get(dev,
> > -						  STMMAC_RESOURCE_NAME);
> > +						   STMMAC_RESOURCE_NAME);
> >  	if (IS_ERR(dwmac->stmmac_rst)) {
> >  		dev_info(dev, "Could not get reset control!\n");
> >  		if (PTR_ERR(dwmac->stmmac_rst) == -EPROBE_DEFER)
> > @@ -99,6 +113,7 @@ static int socfpga_dwmac_parse_data(struct socfpga_dwmac *dwmac, struct device *
> >  	dwmac->interface = of_get_phy_mode(np);
> >
> >  	sys_mgr_base_addr = syscon_regmap_lookup_by_phandle(np, "altr,sysmgr-syscon");
> > +
> >  	if (IS_ERR(sys_mgr_base_addr)) {
> >  		dev_info(dev, "No sysmgr-syscon node found\n");
> >  		return PTR_ERR(sys_mgr_base_addr);
> > @@ -130,6 +145,74 @@ static int socfpga_dwmac_parse_data(struct socfpga_dwmac *dwmac, struct device *
> >  		}
> >  	}
> >
> > +	np_sgmii_adapter = of_parse_phandle(np,
> > +					    "altr,gmii_to_sgmii_converter", 0);
> > +	if (np_sgmii_adapter) {
> > +		index = of_property_match_string(np_sgmii_adapter, "reg-names",
> > +						 "hps_emac_interface_splitter_avalon_slave");
> > +
> > +		if (index >= 0) {
> > +			if (of_address_to_resource(np_sgmii_adapter, index,
> > +						   &res_splitter)) {
> > +				dev_err(dev, "%s: ERROR: missing emac splitter address\n",
> > +					__func__);
> > +				return -EINVAL;
> > +			}
> > +
> > +			dwmac->splitter_base = devm_ioremap_resource(
> > +				dev, &res_splitter);
> > +
> > +			if (IS_ERR(dwmac->splitter_base)) {
> > +				dev_err(dev, "%s: ERROR: failed mapping emac splitter\n",
> > +					__func__);
> > +				return PTR_ERR(dwmac->splitter_base);
> > +			}
> > +		}
> > +
> > +		index = of_property_match_string(np_sgmii_adapter, "reg-names",
> > +						 "gmii_to_sgmii_adapter_avalon_slave");
> > +
> > +		if (index >= 0) {
> > +			if (of_address_to_resource(np_sgmii_adapter, index,
> > +						   &res_sgmii_adapter)) {
> > +				dev_err(dev,
> > +					"%s: ERROR: failed mapping adapter\n",
> > +					__func__);
> > +				return -EINVAL;
> > +			}
> > +
> > +			dwmac->pcs.sgmii_adapter_base =
> > +			devm_ioremap_resource(dev, &res_sgmii_adapter);
> > +
> > +			if (IS_ERR(dwmac->pcs.sgmii_adapter_base)) {
> > +				dev_err(dev, "%s: failed to mapping adapter\n",
> > +					__func__);
> > +				return PTR_ERR(dwmac->pcs.sgmii_adapter_base);
> > +			}
> > +		}
> > +
> > +		index = of_property_match_string(np_sgmii_adapter, "reg-names",
> > +						 "eth_tse_control_port");
> 
> reg-names looks to be specific and mandatory, IMO they should be
> documented in the binding.

That's the binding for the adapter (the phandle to the sgmii adapter),
not the stmac binding itself. Do you mean I should document the sgmii
adapter as well?

> 
> > +
> > +		if (index >= 0) {
> > +			if (of_address_to_resource(np_sgmii_adapter, index,
> > +						   &res_tse_pcs)) {
> > +				dev_err(dev,
> > +					"%s: ERROR: failed mapping tse control port\n",
> > +					__func__);
> > +				return -EINVAL;
> > +			}
> > +
> > +			dwmac->pcs.tse_pcs_base = devm_ioremap_resource(
> > +			dev, &res_tse_pcs);
> 
> can you check with indentation (scripts/Lindent)?

Noted. For some reason check_patch didn't catch this.

> 
> 
> > +
> > +			if (IS_ERR(dwmac->pcs.tse_pcs_base)) {
> > +				dev_err(dev, "%s: ERROR: failed mapping tse control port\n",
> > +					__func__);
> > +				return PTR_ERR(dwmac->pcs.sgmii_adapter_base);
> > +			}
> > +		}
> > +	}
> >  	dwmac->reg_offset = reg_offset;
> >  	dwmac->reg_shift = reg_shift;
> >  	dwmac->sys_mgr_base_addr = sys_mgr_base_addr;
> > @@ -153,6 +236,7 @@ static int socfpga_dwmac_setup(struct socfpga_dwmac *dwmac)
> >  		break;
> >  	case PHY_INTERFACE_MODE_MII:
> >  	case PHY_INTERFACE_MODE_GMII:
> > +	case PHY_INTERFACE_MODE_SGMII:
> >  		val = SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_GMII_MII;
> >  		break;
> >  	default:
> > @@ -172,6 +256,10 @@ static int socfpga_dwmac_setup(struct socfpga_dwmac *dwmac)
> >  	ctrl |= val << reg_shift;
> >
> >  	regmap_write(sys_mgr_base_addr, reg_offset, ctrl);
> > +
> > +	if (phymode == PHY_INTERFACE_MODE_SGMII)
> > +		tse_pcs_init(dwmac->pcs.tse_pcs_base, &dwmac->pcs);
> > +
> >  	return 0;
> >  }
> >
> > @@ -191,6 +279,12 @@ static void *socfpga_dwmac_probe(struct platform_device *pdev)
> >  		return ERR_PTR(ret);
> >  	}
> >
> > +	ret = socfpga_dwmac_setup(dwmac);
> > +	if (ret) {
> > +		dev_err(dev, "couldn't setup SoC glue (%d)\n", ret);
> > +		return ERR_PTR(ret);
> > +	}
> > +
> >  	return dwmac;
> >  }
> >
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/tse_pcs.c b/drivers/net/ethernet/stmicro/stmmac/tse_pcs.c
> > new file mode 100644
> > index 0000000..1989bd1
> > --- /dev/null
> > +++ b/drivers/net/ethernet/stmicro/stmmac/tse_pcs.c
> > @@ -0,0 +1,261 @@
> > +/* Copyright Altera Corporation (C) 2016. All rights reserved.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License, version 2,
> > + * as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> > + *
> > + * Author: Tien Hock Loh <thloh@...era.com>
> > + */
> > +
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/of.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_net.h>
> > +#include <linux/phy.h>
> > +#include <linux/regmap.h>
> > +#include <linux/reset.h>
> > +#include <linux/stmmac.h>
> > +
> > +#include "stmmac.h"
> > +#include "stmmac_platform.h"
> > +#include "tse_pcs.h"
> > +
> > +#define SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_GMII_MII 0x0
> > +#define SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_RGMII 0x1
> > +#define SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_RMII 0x2
> > +#define SYSMGR_EMACGRP_CTRL_PHYSEL_WIDTH 2
> > +#define SYSMGR_EMACGRP_CTRL_PHYSEL_MASK 0x00000003
> > +
> > +#define EMAC_SPLITTER_CTRL_REG			0x0
> > +#define EMAC_SPLITTER_CTRL_SPEED_MASK		0x3
> > +#define EMAC_SPLITTER_CTRL_SPEED_10		0x2
> > +#define EMAC_SPLITTER_CTRL_SPEED_100		0x3
> > +#define EMAC_SPLITTER_CTRL_SPEED_1000		0x0
> 
> pls use BIT and GENMASK.

Noted. Will do the next patch. 

> 
> ...
> 
> > +static void config_tx_buffer(u16 data, void __iomem *base)
> > +{
> > +	writew(data, base + SGMII_ADAPTER_CTRL_REG);
> > +}
> 
> hmm, is this function really necessary?  I think you can use
> directly writew or maybe writew_relaxed.
> 

OK will do. 

> > +
> > +static void tse_pcs_reset(void __iomem *base, struct tse_pcs *pcs)
> > +{
> > +	int counter = 0;
> > +	u16 val;
> > +
> > +	val = readw(base + TSE_PCS_CONTROL_REG);
> > +	val |= TSE_PCS_SW_RST_MASK;
> > +	writew(val, base + TSE_PCS_CONTROL_REG);
> > +
> > +	while (counter < TSE_PCS_SW_RESET_TIMEOUT) {
> > +		val = readw(base + TSE_PCS_CONTROL_REG);
> > +		val &= TSE_PCS_SW_RST_MASK;
> > +		if (val == 0)
> > +			break;
> > +		counter++;
> > +		udelay(1);
> > +	}
> > +	if (counter >= TSE_PCS_SW_RESET_TIMEOUT)
> > +		dev_err(pcs->dev, "PCS could not get out of sw reset\n");
> > +}
> > +
> 
> maybe this should return an error to stop the init if reset is NOK.

Yeah you're right. I'll fix this in the next patch.

> 
> 
> > +void tse_pcs_init(void __iomem *base, struct tse_pcs *pcs)
> > +{
> > +	writew(0x0001, base + TSE_PCS_IF_MODE_REG);
> > +
> > +	writew(TSE_PCS_SGMII_LINK_TIMER_0, base + TSE_PCS_LINK_TIMER_0_REG);
> > +	writew(TSE_PCS_SGMII_LINK_TIMER_1, base + TSE_PCS_LINK_TIMER_1_REG);
> > +
> > +	tse_pcs_reset(base, pcs);
> > +	config_tx_buffer(SGMII_ADAPTER_ENABLE,
> > +			 pcs->sgmii_adapter_base);
> > +}
> > +
> > +static void pcs_link_timer_callback(unsigned long data)
> > +{
> > +	u16 val = 0;
> > +
> > +	struct tse_pcs *pcs = (struct tse_pcs *)data;
> > +	void __iomem *tse_pcs_base = pcs->tse_pcs_base;
> > +	void __iomem *sgmii_adapter_base = pcs->sgmii_adapter_base;
> > +
> > +	val = readw(tse_pcs_base + TSE_PCS_STATUS_REG);
> > +	val &=  TSE_PCS_STATUS_LINK_MASK;
> > +
> > +	if (val != 0) {
> > +		dev_dbg(pcs->dev, "Adapter: Link is established\n");
> > +		config_tx_buffer(SGMII_ADAPTER_ENABLE, sgmii_adapter_base);
> > +	} else {
> > +		mod_timer(&pcs->link_timer, jiffies +
> > +				msecs_to_jiffies(LINK_TIMER));
> > +	}
> > +}
> > +
> > +static void auto_nego_timer_callback(unsigned long data)
> > +{
> > +	u16 val = 0;
> > +	u16 speed = 0;
> > +	u16 duplex = 0;
> > +
> > +	struct tse_pcs *pcs = (struct tse_pcs *)data;
> > +	void __iomem *tse_pcs_base = pcs->tse_pcs_base;
> > +	void __iomem *sgmii_adapter_base = pcs->sgmii_adapter_base;
> > +
> > +	val = readw(tse_pcs_base + TSE_PCS_STATUS_REG);
> > +	val &=  TSE_PCS_STATUS_AN_COMPLETED_MASK;
> > +
> > +	if (val != 0) {
> > +		dev_dbg(pcs->dev, "Adapter: Auto Negotiation is completed\n");
> > +		val = readw(tse_pcs_base + TSE_PCS_PARTNER_ABILITY_REG);
> > +		speed = val & TSE_PCS_PARTNER_SPEED_MASK;
> > +		duplex = val & TSE_PCS_PARTNER_DUPLEX_MASK;
> > +
> > +		if (speed == TSE_PCS_PARTNER_SPEED_10 &&
> > +		    duplex == TSE_PCS_PARTNER_DUPLEX_FULL)
> > +			dev_dbg(pcs->dev,
> > +				"Adapter: Link Partner is Up - 10/Full\n");
> > +		else if (speed == TSE_PCS_PARTNER_SPEED_100 &&
> > +			 duplex == TSE_PCS_PARTNER_DUPLEX_FULL)
> > +			dev_dbg(pcs->dev,
> > +				"Adapter: Link Partner is Up - 100/Full\n");
> > +		else if (speed == TSE_PCS_PARTNER_SPEED_1000 &&
> > +			 duplex == TSE_PCS_PARTNER_DUPLEX_FULL)
> > +			dev_dbg(pcs->dev,
> > +				"Adapter: Link Partner is Up - 1000/Full\n");
> > +		else if (speed == TSE_PCS_PARTNER_SPEED_10 &&
> > +			 duplex == TSE_PCS_PARTNER_DUPLEX_HALF)
> > +			dev_err(pcs->dev,
> > +				"Adapter does not support Half Duplex\n");
> > +		else if (speed == TSE_PCS_PARTNER_SPEED_100 &&
> > +			 duplex == TSE_PCS_PARTNER_DUPLEX_HALF)
> > +			dev_err(pcs->dev,
> > +				"Adapter does not support Half Duplex\n");
> > +		else if (speed == TSE_PCS_PARTNER_SPEED_1000 &&
> > +			 duplex == TSE_PCS_PARTNER_DUPLEX_HALF)
> > +			dev_err(pcs->dev,
> > +				"Adapter does not support Half Duplex\n");
> > +		else
> > +			dev_err(pcs->dev,
> > +				"Adapter: Invalid Partner Speed and Duplex\n");
> 
> ANE is completed but speed or duplex is NOK. Any failure to signalling?
> I see that you then enable the adpter in any case.
> 
> Maybe we could try to restart ANE again or force it (reducing the speed)
> I wonder what happens if, for some reason, there is some hw problem. In
> that case the timer is always running signalling an invalid Parter
> speed. Anyway, this is jus a question... I expect that this error will
> always point us to a problem to debug further (if occurs).

Let me look at how we can handle the case. Perhaps we could do a restart
and register the timer again. I'm just worried it will go into an
infinite timer registering hogging up the kernel if the hardware really
fails. Maybe I can do a n-time retry here. Looking into this. Let me
know if you have any opinions on this.

I haven't been able to check for this behaviour though, negative testing
on this code isn't too easy to simulate.

> 
> > +
> > +		config_tx_buffer(SGMII_ADAPTER_ENABLE, sgmii_adapter_base);
> > +	} else {
> > +		val = readw(tse_pcs_base + TSE_PCS_CONTROL_REG);
> > +		val |= TSE_PCS_CONTROL_RESTART_AN_MASK;
> > +		writew(val, tse_pcs_base + TSE_PCS_CONTROL_REG);
> > +
> > +		tse_pcs_reset(tse_pcs_base, pcs);
> > +		mod_timer(&pcs->an_timer, jiffies +
> > +			  msecs_to_jiffies(AUTONEGO_TIMER));
> > +	}
> > +}
> > +
> > +void tse_pcs_fix_mac_speed(struct tse_pcs *pcs, struct phy_device *phy_dev,
> > +			   unsigned int speed)
> > +{
> > +	void __iomem *tse_pcs_base = pcs->tse_pcs_base;
> > +	void __iomem *sgmii_adapter_base = pcs->sgmii_adapter_base;
> > +	u32 val;
> > +
> > +	config_tx_buffer(SGMII_ADAPTER_DISABLE, sgmii_adapter_base);
> > +
> > +	if (phy_dev->autoneg == AUTONEG_ENABLE) {
> > +		val = readw(tse_pcs_base + TSE_PCS_CONTROL_REG);
> > +		val |= TSE_PCS_CONTROL_AN_EN_MASK;
> > +		writew(val, tse_pcs_base + TSE_PCS_CONTROL_REG);
> > +
> > +		val = readw(tse_pcs_base + TSE_PCS_IF_MODE_REG);
> > +		val |= TSE_PCS_USE_SGMII_AN_MASK;
> > +		writew(val, tse_pcs_base + TSE_PCS_IF_MODE_REG);
> > +
> > +		val = readw(tse_pcs_base + TSE_PCS_CONTROL_REG);
> > +		val |= TSE_PCS_CONTROL_RESTART_AN_MASK;
> > +		writew(val, tse_pcs_base + TSE_PCS_CONTROL_REG);
> > +
> > +		tse_pcs_reset(tse_pcs_base, pcs);
> 
> why do you need to reset here?

This is done according to the Altera TSE specification, whenever a
configuration changes, it is recommended that the PCS gets reset.

> 
> > +
> > +		setup_timer(&pcs->an_timer,
> > +			    auto_nego_timer_callback,
> > +			    (unsigned long)pcs);
> > +		mod_timer(&pcs->an_timer, jiffies +
> > +			  msecs_to_jiffies(AUTONEGO_TIMER));
> > +	} else if (phy_dev->autoneg == AUTONEG_DISABLE) {
> > +		val = readw(tse_pcs_base + TSE_PCS_CONTROL_REG);
> > +		val &= ~TSE_PCS_CONTROL_AN_EN_MASK;
> > +		writew(val, tse_pcs_base + TSE_PCS_CONTROL_REG);
> > +
> > +		val = readw(tse_pcs_base + TSE_PCS_IF_MODE_REG);
> > +		val &= ~TSE_PCS_USE_SGMII_AN_MASK;
> > +		writew(val, tse_pcs_base + TSE_PCS_IF_MODE_REG);
> > +
> > +		val = readw(tse_pcs_base + TSE_PCS_IF_MODE_REG);
> > +		val &= ~TSE_PCS_SGMII_SPEED_MASK;
> > +
> > +		switch (speed) {
> > +		case 1000:
> > +			val |= TSE_PCS_SGMII_SPEED_1000;
> > +			break;
> > +		case 100:
> > +			val |= TSE_PCS_SGMII_SPEED_100;
> > +			break;
> > +		case 10:
> > +			val |= TSE_PCS_SGMII_SPEED_10;
> > +			break;
> > +		default:
> > +			return;
> > +		}
> > +		writew(val, tse_pcs_base + TSE_PCS_IF_MODE_REG);
> > +
> > +		tse_pcs_reset(tse_pcs_base, pcs);
> > +
> > +		setup_timer(&pcs->link_timer,
> > +			    pcs_link_timer_callback,
> > +					(unsigned long)pcs);
> > +		mod_timer(&pcs->link_timer, jiffies +
> > +			  msecs_to_jiffies(LINK_TIMER));
> 
> I wonder if we can have just one timer to manage ANE and LINK.
> 

That would increase the complexity of the code because we would need to
check the callback type on when the callback is triggered and call the
correct function.

> > +	}
> > +}
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/tse_pcs.h b/drivers/net/ethernet/stmicro/stmmac/tse_pcs.h
> > new file mode 100644
> > index 0000000..e3d4511
> > --- /dev/null
> > +++ b/drivers/net/ethernet/stmicro/stmmac/tse_pcs.h
> > @@ -0,0 +1,36 @@
> > +/* Copyright Altera Corporation (C) 2016. All rights reserved.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License, version 2,
> > + * as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> > + *
> > + * Author: Tien Hock Loh <thloh@...era.com>
> > + */
> > +
> > +#ifndef __TSE_PCS_H__
> > +#define __TSE_PCS_H__
> > +
> > +#include <linux/phy.h>
> > +#include <linux/timer.h>
> > +
> > +struct tse_pcs {
> > +	struct device *dev;
> > +	void __iomem *tse_pcs_base;
> > +	void __iomem *sgmii_adapter_base;
> > +	struct timer_list an_timer;
> > +	struct timer_list link_timer;
> > +};
> > +
> > +void tse_pcs_init(void __iomem *base, struct tse_pcs *pcs);
> > +void tse_pcs_fix_mac_speed(struct tse_pcs *pcs, struct phy_device *phy_dev,
> > +			   unsigned int speed);
> > +
> > +#endif /* __TSE_PCS_H__ */
> >
> 

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