From patchwork Fri Mar 22 13:39:28 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Fainelli X-Patchwork-Id: 2320331 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id 1A59E3FD8C for ; Fri, 22 Mar 2013 13:51:27 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UJ2KT-0002xE-I7; Fri, 22 Mar 2013 13:48:21 +0000 Received: from zmc.proxad.net ([212.27.53.206]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UJ2C4-0006K4-TJ for linux-arm-kernel@lists.infradead.org; Fri, 22 Mar 2013 13:39:48 +0000 Received: from localhost (localhost [127.0.0.1]) by zmc.proxad.net (Postfix) with ESMTP id 6D460C5CA5C; Fri, 22 Mar 2013 14:39:37 +0100 (CET) X-Virus-Scanned: amavisd-new at localhost Received: from zmc.proxad.net ([127.0.0.1]) by localhost (zmc.proxad.net [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ZC-OaqJcauin; Fri, 22 Mar 2013 14:39:36 +0100 (CET) Received: from flexo.iliad.local (freebox.vlq16.iliad.fr [213.36.7.13]) by zmc.proxad.net (Postfix) with ESMTPSA id 02131C5CBD8; Fri, 22 Mar 2013 14:39:35 +0100 (CET) From: Florian Fainelli To: davem@davemloft.net Subject: [PATCH 4/4 v3] mv643xx_eth: convert to use the Marvell Orion MDIO driver Date: Fri, 22 Mar 2013 14:39:28 +0100 Message-Id: <1363959568-16976-5-git-send-email-florian@openwrt.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1363959568-16976-1-git-send-email-florian@openwrt.org> References: <1363284515-9865-1-git-send-email-florian@openwrt.org> <1363959568-16976-1-git-send-email-florian@openwrt.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130322_093942_872716_9892700E X-CRM114-Status: GOOD ( 30.70 ) X-Spam-Score: -1.9 (-) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-1.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Thomas Petazzoni , Andrew Lunn , Russell King , Jason Cooper , linux-doc@vger.kernel.org, Benjamin Herrenschmidt , devicetree-discuss@lists.ozlabs.org, linux-kernel@vger.kernel.org, Rob Herring , Grant Likely , netdev@vger.kernel.org, Paul Mackerras , linux-arm-kernel@lists.infradead.org, Rob Landley , Greg Kroah-Hartman , linuxppc-dev@lists.ozlabs.org, Florian Fainelli , Lennert Buytenhek X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org This patch converts the Marvell MV643XX ethernet driver to use the Marvell Orion MDIO driver. As a result, PowerPC and ARM platforms registering the Marvell MV643XX ethernet driver are also updated to register a Marvell Orion MDIO driver. This driver voluntarily overlaps with the Marvell Ethernet shared registers because it will use a subset of this shared register (shared_base + 0x4 to shared_base + 0x84). The Ethernet driver is also updated to look up for a PHY device using the Orion MDIO bus driver. For ARM and PowerPC we register a single instance of the "mvmdio" driver in the system like it used to be done with the use of the "shared_smi" platform_data cookie on ARM. Note that it is safe to register the mvmdio driver only for the "ge00" instance of the driver because this "ge00" interface is guaranteed to always be explicitely registered by consumers of arch/arm/plat-orion/common.c and other instances (ge01, ge10 and ge11) were all pointing their shared_smi to ge00. For PowerPC the in-tree Device Tree Source files mention only one MV643XX ethernet MAC instance so the MDIO bus driver is registered only when id == 0. Signed-off-by: Florian Fainelli --- Changes since v2: - added missing adjust_link callback to phy_connect - removed superfluous phy_attach() call - modified PowerPC code to register a single orion-mdio instance - modified arm code to register a single orion-mdio instance for all GE* interfaces Changes since v1: - removed one too many mdio bus registration for Orion5x/Kirkwood arch/arm/plat-orion/common.c | 54 ++++---- arch/powerpc/platforms/chrp/pegasos_eth.c | 20 +++ arch/powerpc/sysdev/mv64x60_dev.c | 16 ++- drivers/net/ethernet/marvell/Kconfig | 5 +- drivers/net/ethernet/marvell/Makefile | 2 +- drivers/net/ethernet/marvell/mv643xx_eth.c | 195 +++------------------------- include/linux/mv643xx_eth.h | 1 - 7 files changed, 84 insertions(+), 209 deletions(-) diff --git a/arch/arm/plat-orion/common.c b/arch/arm/plat-orion/common.c index 2d4b641..251f827 100644 --- a/arch/arm/plat-orion/common.c +++ b/arch/arm/plat-orion/common.c @@ -238,6 +238,7 @@ static __init void ge_complete( struct mv643xx_eth_shared_platform_data *orion_ge_shared_data, struct resource *orion_ge_resource, unsigned long irq, struct platform_device *orion_ge_shared, + struct platform_device *orion_ge_mvmdio, struct mv643xx_eth_platform_data *eth_data, struct platform_device *orion_ge) { @@ -247,6 +248,8 @@ static __init void ge_complete( orion_ge->dev.platform_data = eth_data; platform_device_register(orion_ge_shared); + if (orion_ge_mvmdio) + platform_device_register(orion_ge_mvmdio); platform_device_register(orion_ge); } @@ -258,8 +261,6 @@ struct mv643xx_eth_shared_platform_data orion_ge00_shared_data; static struct resource orion_ge00_shared_resources[] = { { .name = "ge00 base", - }, { - .name = "ge00 err irq", }, }; @@ -271,6 +272,19 @@ static struct platform_device orion_ge00_shared = { }, }; +static struct resource orion_ge_mvmdio_resources[] = { + { + .name = "ge00 mvmdio base", + }, { + .name = "ge00 mvmdio err irq", + }, +}; + +static struct platform_device orion_ge_mvmdio = { + .name = "orion-mdio", + .id = -1, +}; + static struct resource orion_ge00_resources[] = { { .name = "ge00 irq", @@ -295,26 +309,25 @@ void __init orion_ge00_init(struct mv643xx_eth_platform_data *eth_data, unsigned int tx_csum_limit) { fill_resources(&orion_ge00_shared, orion_ge00_shared_resources, - mapbase + 0x2000, SZ_16K - 1, irq_err); + mapbase + 0x2000, SZ_16K - 1, NO_IRQ); + fill_resources(&orion_ge_mvmdio, orion_ge_mvmdio_resources, + mapbase + 0x2004, 0x84 - 1, irq_err); orion_ge00_shared_data.tx_csum_limit = tx_csum_limit; ge_complete(&orion_ge00_shared_data, orion_ge00_resources, irq, &orion_ge00_shared, + &orion_ge_mvmdio, eth_data, &orion_ge00); } /***************************************************************************** * GE01 ****************************************************************************/ -struct mv643xx_eth_shared_platform_data orion_ge01_shared_data = { - .shared_smi = &orion_ge00_shared, -}; +struct mv643xx_eth_shared_platform_data orion_ge01_shared_data; static struct resource orion_ge01_shared_resources[] = { { .name = "ge01 base", - }, { - .name = "ge01 err irq", - }, + } }; static struct platform_device orion_ge01_shared = { @@ -349,26 +362,23 @@ void __init orion_ge01_init(struct mv643xx_eth_platform_data *eth_data, unsigned int tx_csum_limit) { fill_resources(&orion_ge01_shared, orion_ge01_shared_resources, - mapbase + 0x2000, SZ_16K - 1, irq_err); + mapbase + 0x2000, SZ_16K - 1, NO_IRQ); orion_ge01_shared_data.tx_csum_limit = tx_csum_limit; ge_complete(&orion_ge01_shared_data, orion_ge01_resources, irq, &orion_ge01_shared, + NULL, eth_data, &orion_ge01); } /***************************************************************************** * GE10 ****************************************************************************/ -struct mv643xx_eth_shared_platform_data orion_ge10_shared_data = { - .shared_smi = &orion_ge00_shared, -}; +struct mv643xx_eth_shared_platform_data orion_ge10_shared_data; static struct resource orion_ge10_shared_resources[] = { { .name = "ge10 base", - }, { - .name = "ge10 err irq", - }, + } }; static struct platform_device orion_ge10_shared = { @@ -402,24 +412,21 @@ void __init orion_ge10_init(struct mv643xx_eth_platform_data *eth_data, unsigned long irq_err) { fill_resources(&orion_ge10_shared, orion_ge10_shared_resources, - mapbase + 0x2000, SZ_16K - 1, irq_err); + mapbase + 0x2000, SZ_16K - 1, NO_IRQ); ge_complete(&orion_ge10_shared_data, orion_ge10_resources, irq, &orion_ge10_shared, + NULL, eth_data, &orion_ge10); } /***************************************************************************** * GE11 ****************************************************************************/ -struct mv643xx_eth_shared_platform_data orion_ge11_shared_data = { - .shared_smi = &orion_ge00_shared, -}; +struct mv643xx_eth_shared_platform_data orion_ge11_shared_data; static struct resource orion_ge11_shared_resources[] = { { .name = "ge11 base", - }, { - .name = "ge11 err irq", }, }; @@ -454,9 +461,10 @@ void __init orion_ge11_init(struct mv643xx_eth_platform_data *eth_data, unsigned long irq_err) { fill_resources(&orion_ge11_shared, orion_ge11_shared_resources, - mapbase + 0x2000, SZ_16K - 1, irq_err); + mapbase + 0x2000, SZ_16K - 1, NO_IRQ); ge_complete(&orion_ge11_shared_data, orion_ge11_resources, irq, &orion_ge11_shared, + NULL, eth_data, &orion_ge11); } diff --git a/arch/powerpc/platforms/chrp/pegasos_eth.c b/arch/powerpc/platforms/chrp/pegasos_eth.c index 039fc8e..2b4dc6a 100644 --- a/arch/powerpc/platforms/chrp/pegasos_eth.c +++ b/arch/powerpc/platforms/chrp/pegasos_eth.c @@ -47,6 +47,25 @@ static struct platform_device mv643xx_eth_shared_device = { .resource = mv643xx_eth_shared_resources, }; +/* + * The orion mdio driver only covers shared + 0x4 up to shared + 0x84 - 1 + */ +static struct resource mv643xx_eth_mvmdio_resources[] = { + [0] = { + .name = "ethernet mdio base", + .start = 0xf1000000 + MV643XX_ETH_SHARED_REGS + 0x4, + .end = 0xf1000000 + MV643XX_ETH_SHARED_REGS + 0x83, + .flags = IORESOURCE_MEM, + }, +}; + +static struct platform_device mv643xx_eth_mvmdio_device = { + .name = "orion-mdio", + .id = -1, + .num_resources = ARRAY_SIZE(mv643xx_eth_mvmdio_resources), + .resource = mv643xx_eth_shared_resources, +}; + static struct resource mv643xx_eth_port1_resources[] = { [0] = { .name = "eth port1 irq", @@ -82,6 +101,7 @@ static struct platform_device eth_port1_device = { static struct platform_device *mv643xx_eth_pd_devs[] __initdata = { &mv643xx_eth_shared_device, + &mv643xx_eth_mvmdio_device, ð_port1_device, }; diff --git a/arch/powerpc/sysdev/mv64x60_dev.c b/arch/powerpc/sysdev/mv64x60_dev.c index 0f6af41..4a25c26 100644 --- a/arch/powerpc/sysdev/mv64x60_dev.c +++ b/arch/powerpc/sysdev/mv64x60_dev.c @@ -214,15 +214,27 @@ static struct platform_device * __init mv64x60_eth_register_shared_pdev( struct device_node *np, int id) { struct platform_device *pdev; - struct resource r[1]; + struct resource r[2]; int err; err = of_address_to_resource(np, 0, &r[0]); if (err) return ERR_PTR(err); + /* register an orion mdio bus driver */ + r[1].start = r[0].start + 0x4; + r[1].end = r[0].start + 0x84 - 1; + r[1].flags = IORESOURCE_MEM; + + if (id == 0) { + pdev = platform_device_register_simple("orion-mdio", -1, &r[1], 1); + if (!pdev) + return pdev; + } + pdev = platform_device_register_simple(MV643XX_ETH_SHARED_NAME, id, - r, 1); + &r[0], 1); + return pdev; } diff --git a/drivers/net/ethernet/marvell/Kconfig b/drivers/net/ethernet/marvell/Kconfig index edfba93..5170ecb 100644 --- a/drivers/net/ethernet/marvell/Kconfig +++ b/drivers/net/ethernet/marvell/Kconfig @@ -23,6 +23,7 @@ config MV643XX_ETH depends on (MV64X60 || PPC32 || PLAT_ORION) && INET select INET_LRO select PHYLIB + select MVMDIO ---help--- This driver supports the gigabit ethernet MACs in the Marvell Discovery PPC/MIPS chipset family (MV643XX) and @@ -38,9 +39,7 @@ config MVMDIO interface units of the Marvell EBU SoCs (Kirkwood, Orion5x, Dove, Armada 370 and Armada XP). - For now, this driver is only needed for the MVNETA driver - (used on Armada 370 and XP), but it could be used in the - future by the MV643XX_ETH driver. + This driver is used by the MV643XX_ETH and MVNETA drivers. config MVNETA tristate "Marvell Armada 370/XP network interface support" diff --git a/drivers/net/ethernet/marvell/Makefile b/drivers/net/ethernet/marvell/Makefile index 7f63b4a..5c4a776 100644 --- a/drivers/net/ethernet/marvell/Makefile +++ b/drivers/net/ethernet/marvell/Makefile @@ -2,8 +2,8 @@ # Makefile for the Marvell device drivers. # -obj-$(CONFIG_MV643XX_ETH) += mv643xx_eth.o obj-$(CONFIG_MVMDIO) += mvmdio.o +obj-$(CONFIG_MV643XX_ETH) += mv643xx_eth.o obj-$(CONFIG_MVNETA) += mvneta.o obj-$(CONFIG_PXA168_ETH) += pxa168_eth.o obj-$(CONFIG_SKGE) += skge.o diff --git a/drivers/net/ethernet/marvell/mv643xx_eth.c b/drivers/net/ethernet/marvell/mv643xx_eth.c index d1ecf4b..a65a92e 100644 --- a/drivers/net/ethernet/marvell/mv643xx_eth.c +++ b/drivers/net/ethernet/marvell/mv643xx_eth.c @@ -69,14 +69,6 @@ static char mv643xx_eth_driver_version[] = "1.4"; * Registers shared between all ports. */ #define PHY_ADDR 0x0000 -#define SMI_REG 0x0004 -#define SMI_BUSY 0x10000000 -#define SMI_READ_VALID 0x08000000 -#define SMI_OPCODE_READ 0x04000000 -#define SMI_OPCODE_WRITE 0x00000000 -#define ERR_INT_CAUSE 0x0080 -#define ERR_INT_SMI_DONE 0x00000010 -#define ERR_INT_MASK 0x0084 #define WINDOW_BASE(w) (0x0200 + ((w) << 3)) #define WINDOW_SIZE(w) (0x0204 + ((w) << 3)) #define WINDOW_REMAP_HIGH(w) (0x0280 + ((w) << 2)) @@ -266,25 +258,6 @@ struct mv643xx_eth_shared_private { void __iomem *base; /* - * Points at the right SMI instance to use. - */ - struct mv643xx_eth_shared_private *smi; - - /* - * Provides access to local SMI interface. - */ - struct mii_bus *smi_bus; - - /* - * If we have access to the error interrupt pin (which is - * somewhat misnamed as it not only reflects internal errors - * but also reflects SMI completion), use that to wait for - * SMI access completion instead of polling the SMI busy bit. - */ - int err_interrupt; - wait_queue_head_t smi_busy_wait; - - /* * Per-port MBUS window access register value. */ u32 win_protect; @@ -1122,97 +1095,6 @@ out_write: wrlp(mp, PORT_SERIAL_CONTROL, pscr); } -static irqreturn_t mv643xx_eth_err_irq(int irq, void *dev_id) -{ - struct mv643xx_eth_shared_private *msp = dev_id; - - if (readl(msp->base + ERR_INT_CAUSE) & ERR_INT_SMI_DONE) { - writel(~ERR_INT_SMI_DONE, msp->base + ERR_INT_CAUSE); - wake_up(&msp->smi_busy_wait); - return IRQ_HANDLED; - } - - return IRQ_NONE; -} - -static int smi_is_done(struct mv643xx_eth_shared_private *msp) -{ - return !(readl(msp->base + SMI_REG) & SMI_BUSY); -} - -static int smi_wait_ready(struct mv643xx_eth_shared_private *msp) -{ - if (msp->err_interrupt == NO_IRQ) { - int i; - - for (i = 0; !smi_is_done(msp); i++) { - if (i == 10) - return -ETIMEDOUT; - msleep(10); - } - - return 0; - } - - if (!smi_is_done(msp)) { - wait_event_timeout(msp->smi_busy_wait, smi_is_done(msp), - msecs_to_jiffies(100)); - if (!smi_is_done(msp)) - return -ETIMEDOUT; - } - - return 0; -} - -static int smi_bus_read(struct mii_bus *bus, int addr, int reg) -{ - struct mv643xx_eth_shared_private *msp = bus->priv; - void __iomem *smi_reg = msp->base + SMI_REG; - int ret; - - if (smi_wait_ready(msp)) { - pr_warn("SMI bus busy timeout\n"); - return -ETIMEDOUT; - } - - writel(SMI_OPCODE_READ | (reg << 21) | (addr << 16), smi_reg); - - if (smi_wait_ready(msp)) { - pr_warn("SMI bus busy timeout\n"); - return -ETIMEDOUT; - } - - ret = readl(smi_reg); - if (!(ret & SMI_READ_VALID)) { - pr_warn("SMI bus read not valid\n"); - return -ENODEV; - } - - return ret & 0xffff; -} - -static int smi_bus_write(struct mii_bus *bus, int addr, int reg, u16 val) -{ - struct mv643xx_eth_shared_private *msp = bus->priv; - void __iomem *smi_reg = msp->base + SMI_REG; - - if (smi_wait_ready(msp)) { - pr_warn("SMI bus busy timeout\n"); - return -ETIMEDOUT; - } - - writel(SMI_OPCODE_WRITE | (reg << 21) | - (addr << 16) | (val & 0xffff), smi_reg); - - if (smi_wait_ready(msp)) { - pr_warn("SMI bus busy timeout\n"); - return -ETIMEDOUT; - } - - return 0; -} - - /* statistics ***************************************************************/ static struct net_device_stats *mv643xx_eth_get_stats(struct net_device *dev) { @@ -2688,47 +2570,6 @@ static int mv643xx_eth_shared_probe(struct platform_device *pdev) goto out_free; /* - * Set up and register SMI bus. - */ - if (pd == NULL || pd->shared_smi == NULL) { - msp->smi_bus = mdiobus_alloc(); - if (msp->smi_bus == NULL) - goto out_unmap; - - msp->smi_bus->priv = msp; - msp->smi_bus->name = "mv643xx_eth smi"; - msp->smi_bus->read = smi_bus_read; - msp->smi_bus->write = smi_bus_write, - snprintf(msp->smi_bus->id, MII_BUS_ID_SIZE, "%s-%d", - pdev->name, pdev->id); - msp->smi_bus->parent = &pdev->dev; - msp->smi_bus->phy_mask = 0xffffffff; - if (mdiobus_register(msp->smi_bus) < 0) - goto out_free_mii_bus; - msp->smi = msp; - } else { - msp->smi = platform_get_drvdata(pd->shared_smi); - } - - msp->err_interrupt = NO_IRQ; - init_waitqueue_head(&msp->smi_busy_wait); - - /* - * Check whether the error interrupt is hooked up. - */ - res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); - if (res != NULL) { - int err; - - err = request_irq(res->start, mv643xx_eth_err_irq, - IRQF_SHARED, "mv643xx_eth", msp); - if (!err) { - writel(ERR_INT_SMI_DONE, msp->base + ERR_INT_MASK); - msp->err_interrupt = res->start; - } - } - - /* * (Re-)program MBUS remapping windows if we are asked to. */ dram = mv_mbus_dram_info(); @@ -2743,10 +2584,6 @@ static int mv643xx_eth_shared_probe(struct platform_device *pdev) return 0; -out_free_mii_bus: - mdiobus_free(msp->smi_bus); -out_unmap: - iounmap(msp->base); out_free: kfree(msp); out: @@ -2756,14 +2593,7 @@ out: static int mv643xx_eth_shared_remove(struct platform_device *pdev) { struct mv643xx_eth_shared_private *msp = platform_get_drvdata(pdev); - struct mv643xx_eth_shared_platform_data *pd = pdev->dev.platform_data; - if (pd == NULL || pd->shared_smi == NULL) { - mdiobus_unregister(msp->smi_bus); - mdiobus_free(msp->smi_bus); - } - if (msp->err_interrupt != NO_IRQ) - free_irq(msp->err_interrupt, msp); iounmap(msp->base); kfree(msp); @@ -2826,14 +2656,21 @@ static void set_params(struct mv643xx_eth_private *mp, mp->txq_count = pd->tx_queue_count ? : 1; } +static void mv643xx_eth_adjust_link(struct net_device *dev) +{ + struct mv643xx_eth_private *mp = netdev_priv(dev); + + mv643xx_adjust_pscr(mp); +} + static struct phy_device *phy_scan(struct mv643xx_eth_private *mp, int phy_addr) { - struct mii_bus *bus = mp->shared->smi->smi_bus; struct phy_device *phydev; int start; int num; int i; + char phy_id[MII_BUS_ID_SIZE + 3]; if (phy_addr == MV643XX_ETH_PHY_ADDR_DEFAULT) { start = phy_addr_get(mp) & 0x1f; @@ -2843,17 +2680,19 @@ static struct phy_device *phy_scan(struct mv643xx_eth_private *mp, num = 1; } + /* Attempt to connect to the PHY using orion-mdio */ phydev = NULL; for (i = 0; i < num; i++) { int addr = (start + i) & 0x1f; - if (bus->phy_map[addr] == NULL) - mdiobus_scan(bus, addr); + snprintf(phy_id, sizeof(phy_id), PHY_ID_FMT, + "orion-mdio-mii", addr); - if (phydev == NULL) { - phydev = bus->phy_map[addr]; - if (phydev != NULL) - phy_addr_set(mp, addr); + phydev = phy_connect(mp->dev, phy_id, mv643xx_eth_adjust_link, + PHY_INTERFACE_MODE_GMII); + if (!IS_ERR(phydev)) { + phy_addr_set(mp, addr); + break; } } @@ -2866,8 +2705,6 @@ static void phy_init(struct mv643xx_eth_private *mp, int speed, int duplex) phy_reset(mp); - phy_attach(mp->dev, dev_name(&phy->dev), PHY_INTERFACE_MODE_GMII); - if (speed == 0) { phy->autoneg = AUTONEG_ENABLE; phy->speed = 0; diff --git a/include/linux/mv643xx_eth.h b/include/linux/mv643xx_eth.h index 49258e0..141d395 100644 --- a/include/linux/mv643xx_eth.h +++ b/include/linux/mv643xx_eth.h @@ -19,7 +19,6 @@ struct mv643xx_eth_shared_platform_data { struct mbus_dram_target_info *dram; - struct platform_device *shared_smi; /* * Max packet size for Tx IP/Layer 4 checksum, when set to 0, default * limit of 9KiB will be used.