Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754446AbcDMWSn (ORCPT ); Wed, 13 Apr 2016 18:18:43 -0400 Received: from mail-pa0-f66.google.com ([209.85.220.66]:33630 "EHLO mail-pa0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754271AbcDMWSi (ORCPT ); Wed, 13 Apr 2016 18:18:38 -0400 Subject: Re: [PATCH 1/2] [v4] net: emac: emac gigabit ethernet controller driver To: Timur Tabi , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, sdharia@codeaurora.org, Shanker Donthineni , Greg Kroah-Hartman , vikrams@codeaurora.org, cov@codeaurora.org, gavidov@codeaurora.org, Rob Herring , andrew@lunn.ch, bjorn.andersson@linaro.org, Mark Langsdorf , Jon Masters , Andy Gross , "David S. Miller" References: <1460570393-19838-1-git-send-email-timur@codeaurora.org> From: Florian Fainelli Message-ID: <570EC541.6080603@gmail.com> Date: Wed, 13 Apr 2016 15:16:33 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1460570393-19838-1-git-send-email-timur@codeaurora.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 20694 Lines: 716 On 13/04/16 10:59, Timur Tabi wrote: > From: Gilad Avidov > > Add supports for ethernet controller HW on Qualcomm Technologies, Inc. SoC. > This driver supports the following features: > 1) Checksum offload. > 2) Runtime power management support. > 3) Interrupt coalescing support. > 4) SGMII phy. > 5) SGMII direct connection without external phy. I think you should shoot for more simple for an initial submission: - no offload - no timestamping get that accepted, and then add features one by one, it sure is more work, but it helps with the review, and makes you work off a solid base. You will see below, but a pet peeve of mine is authors reimplementing code that exists in PHYLIB. [snip] > diff --git a/Documentation/devicetree/bindings/net/qcom-emac.txt b/Documentation/devicetree/bindings/net/qcom-emac.txt > new file mode 100644 > index 0000000..df5e7c0 > --- /dev/null > +++ b/Documentation/devicetree/bindings/net/qcom-emac.txt > @@ -0,0 +1,65 @@ > +Qualcomm EMAC Gigabit Ethernet Controller > + > +Required properties: > +- compatible : Should be "qcom,emac". > +- reg : Offset and length of the register regions for the device > +- reg-names : Register region names referenced in 'reg' above. > + Required register resource entries are: > + "base" : EMAC controller base register block. > + "csr" : EMAC wrapper register block. > + Optional register resource entries are: > + "ptp" : EMAC PTP (1588) register block. > + Required if 'qcom,emac-tstamp-en' is present. > + "sgmii" : EMAC SGMII PHY register block. > +- interrupts : Interrupt numbers used by this controller > +- interrupt-names : Interrupt resource names referenced in 'interrupts' above. > + Required interrupt resource entries are: > + "emac_core0" : EMAC core0 interrupt. > + "sgmii_irq" : EMAC SGMII interrupt. > +- phy-addr : Specifies phy address on MDIO bus. > + Required if the optional property "qcom,no-external-phy" > + is not specified. This is not the standard way to represent an Ethernet PHY hanging off a MDIO bus see ethernet.txt and phy.txt in D/dt/bindings/net/ > + > +Optional properties: > +- qcom,emac-tstamp-en : Enables the PTP (1588) timestamping feature. > + Include this only if PTP (1588) timestamping > + feature is needed. If included, "ptp" register > + base should be specified. If the "ptp" register range is not specified, then PTP gets disabled, so is a boolean really required here, considering that this looks like a policy decision more than anything. > +- mac-address : The 6-byte MAC address. If present, it is the > + default MAC address. This property is pretty much mandatory > +- qcom,no-external-phy : Indicates there is no external PHY connected to > + EMAC. Include this only if the EMAC is directly > + connected to the peer end without EPHY. How is the internal PHY accessed, is it responding on the MDIO bus at a particular address? If so, standard MDIO scanning/probing works, and you can have your PHY driver flag this device has internal. Worst case, you can do what BCMGENET does, and have a special "phy-mode" value set to "internal" when this knowledge needs to exist prior to MDIO bus scanning (e.g: to power on the PHY). > +Example: > + emac0: qcom,emac@feb20000 { > + compatible = "qcom,fsm9900-emac"; > + reg-names = "base", "csr", "ptp", "sgmii"; > + reg = <0xfeb20000 0x10000>, > + <0xfeb36000 0x1000>, > + <0xfeb3c000 0x4000>, > + <0xfeb38000 0x400>; > + #address-cells = <0>; > + interrupt-parent = <&emac0>; > + #interrupt-cells = <1>; > + interrupts = <0 1>; > + interrupt-map-mask = <0xffffffff>; > + interrupt-map = <0 &intc 0 76 0 > + 1 &intc 0 80 0>; > + interrupt-names = "emac_core0", "sgmii_irq"; > + qcom,emac-tstamp-en; > + phy-addr = <0>; > + > + pinctrl-names = "default"; > + pinctrl-0 = <&mdio_pins_a>; > + }; > + > + tlmm: pinctrl@fd510000 { > + compatible = "qcom,fsm9900-pinctrl"; > + > + mdio_pins_a: mdio { > + state { > + pins = "gpio123", "gpio124"; > + function = "mdio"; > + }; > + }; > + }; > diff --git a/drivers/net/ethernet/qualcomm/Kconfig b/drivers/net/ethernet/qualcomm/Kconfig > index a76e380..85b599f 100644 > --- a/drivers/net/ethernet/qualcomm/Kconfig > +++ b/drivers/net/ethernet/qualcomm/Kconfig > @@ -24,4 +24,15 @@ config QCA7000 > To compile this driver as a module, choose M here. The module > will be called qcaspi. > > +config QCOM_EMAC > + tristate "Qualcomm Technologies, Inc. EMAC Gigabit Ethernet support" > + select CRC32 > + ---help--- > + This driver supports the Qualcomm Technologies, Inc. Gigabit > + Ethernet Media Access Controller (EMAC). The controller > + supports IEEE 802.3-2002, half-duplex mode at 10/100 Mb/s, > + full-duplex mode at 10/100/1000Mb/s, Wake On LAN (WOL) for > + low power, Receive-Side Scaling (RSS), and IEEE 1588-2008 > + Precision Clock Synchronization Protocol. > + > endif # NET_VENDOR_QUALCOMM [snip] > +/* Config MAC modes */ > +void emac_mac_mode_config(struct emac_adapter *adpt) > +{ > + u32 mac; > + > + mac = readl(adpt->base + EMAC_MAC_CTRL); > + > + if (test_bit(EMAC_STATUS_VLANSTRIP_EN, &adpt->status)) > + mac |= VLAN_STRIP; > + else > + mac &= ~VLAN_STRIP; > + > + if (test_bit(EMAC_STATUS_PROMISC_EN, &adpt->status)) > + mac |= PROM_MODE; > + else > + mac &= ~PROM_MODE; > + > + if (test_bit(EMAC_STATUS_MULTIALL_EN, &adpt->status)) > + mac |= MULTI_ALL; > + else > + mac &= ~MULTI_ALL; > + > + if (test_bit(EMAC_STATUS_LOOPBACK_EN, &adpt->status)) > + mac |= MAC_LP_EN; > + else > + mac &= ~MAC_LP_EN; Do you need to maintain these flags when most, if not all of them already exist in dev->flags or dev->features? [snip] > + /* setup link speed */ > + mac &= ~SPEED_BMSK; > + switch (phy->link_speed) { > + case EMAC_LINK_SPEED_1GB_FULL: > + mac |= ((emac_mac_speed_1000 << SPEED_SHFT) & SPEED_BMSK); > + csr1 |= FREQ_MODE; > + break; > + default: > + mac |= ((emac_mac_speed_10_100 << SPEED_SHFT) & SPEED_BMSK); > + csr1 &= ~FREQ_MODE; > + break; > + } If you implement the driver using PHYLIB, which you should in order to support arbitrary or internal PHYs, then this function gets invoked whenever there is a link parameter change (auto-neg, forcing, duplex/speed/no link etc.). [snip] > + napi_enable(&adpt->rx_q.napi); > + > + /* enable mac irq */ > + writel(~DIS_INT, adpt->base + EMAC_INT_STATUS); > + writel(adpt->irq.mask, adpt->base + EMAC_INT_MASK); > + > + netif_start_queue(netdev); Starting the TX queue is typically the last ting you want to do, to avoid a transient state where the TX queue is enabled, and the link is not (which is okay if your driver is properly implemented and reflects carrier changes anyway). > + clear_bit(EMAC_STATUS_DOWN, &adpt->status); > + > + /* check link status */ > + set_bit(EMAC_STATUS_TASK_LSC_REQ, &adpt->status); > + adpt->link_chk_timeout = jiffies + EMAC_TRY_LINK_TIMEOUT; > + mod_timer(&adpt->timers, jiffies); Please implement a PHYLIB driver and use phy_start() here. > + > + return 0; > +} > + > +/* Bring down the interface/HW */ > +void emac_mac_down(struct emac_adapter *adpt, bool reset) > +{ > + struct net_device *netdev = adpt->netdev; > + struct emac_phy *phy = &adpt->phy; > + unsigned long flags; > + > + set_bit(EMAC_STATUS_DOWN, &adpt->status); Do you need to maintain that? Would not netif_running() tell you what you want if you reflect the carrier state properly? > + > + netif_stop_queue(netdev); > + netif_carrier_off(netdev); phy_stop() would take care of the latter. [snip] > +/* Process transmit event */ > +void emac_mac_tx_process(struct emac_adapter *adpt, struct emac_tx_queue *tx_q) > +{ > + struct emac_buffer *tpbuf; > + u32 hw_consume_idx; > + u32 pkts_compl = 0, bytes_compl = 0; > + u32 reg = readl_relaxed(adpt->base + tx_q->consume_reg); > + > + hw_consume_idx = (reg & tx_q->consume_mask) >> tx_q->consume_shift; > + > + while (tx_q->tpd.consume_idx != hw_consume_idx) { > + tpbuf = GET_TPD_BUFFER(tx_q, tx_q->tpd.consume_idx); > + if (tpbuf->dma_addr) { > + dma_unmap_single(adpt->netdev->dev.parent, > + tpbuf->dma_addr, tpbuf->length, > + DMA_TO_DEVICE); > + tpbuf->dma_addr = 0; > + } > + > + if (tpbuf->skb) { > + pkts_compl++; > + bytes_compl += tpbuf->skb->len; > + dev_kfree_skb_irq(tpbuf->skb); > + tpbuf->skb = NULL; > + } > + > + if (++tx_q->tpd.consume_idx == tx_q->tpd.count) > + tx_q->tpd.consume_idx = 0; > + } > + > + if (pkts_compl || bytes_compl) > + netdev_completed_queue(adpt->netdev, pkts_compl, bytes_compl); The condition can be eliminated. [snip] > + if (skb_network_offset(skb) != ETH_HLEN) > + TPD_TYP_SET(&tpd, 1); > + > + emac_tx_fill_tpd(adpt, tx_q, skb, &tpd); > + > + netdev_sent_queue(adpt->netdev, skb->len); > + > + /* update produce idx */ > + prod_idx = (tx_q->tpd.produce_idx << tx_q->produce_shift) & > + tx_q->produce_mask; > + emac_reg_update32(adpt->base + tx_q->produce_reg, > + tx_q->produce_mask, prod_idx); Since you have a producer index, you should consider checking skb->xmit_more to know whether you can update the register now, or later, which could save some expensive operation and batch TX. [snip] > diff --git a/drivers/net/ethernet/qualcomm/emac/emac-phy.c b/drivers/net/ethernet/qualcomm/emac/emac-phy.c > new file mode 100644 > index 0000000..7d18de3 > --- /dev/null > +++ b/drivers/net/ethernet/qualcomm/emac/emac-phy.c This file is really really ugly, and duplicates a lot of functionality provided by PHYLIB, you really need to implement a PHYLIB MDIO driver and eventually a small PHY driver for your internal PHY if it needs some baby sitting. [snip] > diff --git a/drivers/net/ethernet/qualcomm/emac/emac.c b/drivers/net/ethernet/qualcomm/emac/emac.c > new file mode 100644 > index 0000000..ce328f5 > --- /dev/null > +++ b/drivers/net/ethernet/qualcomm/emac/emac.c > @@ -0,0 +1,1206 @@ > +/* Copyright (c) 2013-2016, The Linux Foundation. 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 and > + * only 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. > + */ > + > +/* Qualcomm Technologies, Inc. EMAC Gigabit Ethernet Driver > + * The EMAC driver supports following features: > + * 1) Receive Side Scaling (RSS). > + * 2) Checksum offload. > + * 3) Multiple PHY support on MDIO bus. > + * 4) Runtime power management support. > + * 5) Interrupt coalescing support. > + * 6) SGMII phy. > + * 7) SGMII direct connection (without external phy). > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include "emac.h" > +#include "emac-mac.h" > +#include "emac-phy.h" > +#include "emac-sgmii.h" > + > +#define DRV_VERSION "1.3.0.0" > + > +static int debug = -1; > +module_param(debug, int, S_IRUGO | S_IWUSR | S_IWGRP); ethtool -s msglvl provides you with that already. > + > +static int emac_irq_use_extended; > +module_param(emac_irq_use_extended, int, S_IRUGO | S_IWUSR | S_IWGRP); What is that module parameter used for? > + > +const char emac_drv_name[] = "qcom-emac"; > +const char emac_drv_description[] = > + "Qualcomm Technologies, Inc. EMAC Ethernet Driver"; > +const char emac_drv_version[] = DRV_VERSION; Static all other the place? [snip] > + > +/* NAPI */ > +static int emac_napi_rtx(struct napi_struct *napi, int budget) > +{ > + struct emac_rx_queue *rx_q = container_of(napi, struct emac_rx_queue, > + napi); > + struct emac_adapter *adpt = netdev_priv(rx_q->netdev); > + struct emac_irq *irq = rx_q->irq; > + > + int work_done = 0; > + > + /* Keep link state information with original netdev */ > + if (!netif_carrier_ok(adpt->netdev)) > + goto quit_polling; I do not think this is a condition that could occur? > + > + emac_mac_rx_process(adpt, rx_q, &work_done, budget); > + > + if (work_done < budget) { > +quit_polling: > + napi_complete(napi); > + > + irq->mask |= rx_q->intr; > + writel(irq->mask, adpt->base + EMAC_INT_MASK); > + } > + > + return work_done; > +} > + > +/* Transmit the packet */ > +static int emac_start_xmit(struct sk_buff *skb, struct net_device *netdev) > +{ > + struct emac_adapter *adpt = netdev_priv(netdev); > + > + return emac_mac_tx_buf_send(adpt, &adpt->tx_q, skb); I would inline emac_mac_tx_buf_send()'s body here to make it much easier to read and audit... > +} > + > +irqreturn_t emac_isr(int _irq, void *data) > +{ > + struct emac_irq *irq = data; > + struct emac_adapter *adpt = container_of(irq, struct emac_adapter, irq); > + struct emac_rx_queue *rx_q = &adpt->rx_q; > + > + int max_ints = 1; > + u32 isr, status; > + > + /* disable the interrupt */ > + writel(0, adpt->base + EMAC_INT_MASK); > + > + do { With max_ints = 1, this is essentially the same as no loop, so just inline it to reduce the indentation. > + isr = readl_relaxed(adpt->base + EMAC_INT_STATUS); > + status = isr & irq->mask; > + > + if (status == 0) > + break; > + > + if (status & ISR_ERROR) { > + netif_warn(adpt, intr, adpt->netdev, > + "warning: error irq status 0x%lx\n", > + status & ISR_ERROR); > + /* reset MAC */ > + set_bit(EMAC_STATUS_TASK_REINIT_REQ, &adpt->status); > + emac_work_thread_reschedule(adpt); > + } > + > + /* Schedule the napi for receive queue with interrupt > + * status bit set > + */ > + if ((status & rx_q->intr)) { > + if (napi_schedule_prep(&rx_q->napi)) { > + irq->mask &= ~rx_q->intr; > + __napi_schedule(&rx_q->napi); > + } > + } > + > + if (status & TX_PKT_INT) > + emac_mac_tx_process(adpt, &adpt->tx_q); You should consider using a NAPI instance for reclaiming TX buffers as well. > + > + if (status & ISR_OVER) > + netif_warn(adpt, intr, adpt->netdev, > + "warning: TX/RX overflow status 0x%lx\n", > + status & ISR_OVER); This should be ratelimited presumably > + > + /* link event */ > + if (status & (ISR_GPHY_LINK | SW_MAN_INT)) { > + emac_lsc_schedule_check(adpt); > + break; > + } > + } while (--max_ints > 0); > + > + /* enable the interrupt */ > + writel(irq->mask, adpt->base + EMAC_INT_MASK); > + > + return IRQ_HANDLED; > +} > + > +/* Configure VLAN tag strip/insert feature */ > +static int emac_set_features(struct net_device *netdev, > + netdev_features_t features) > +{ > + struct emac_adapter *adpt = netdev_priv(netdev); > + > + netdev_features_t changed = features ^ netdev->features; > + > + if (!(changed & (NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX))) > + return 0; > + > + netdev->features = features; > + if (netdev->features & NETIF_F_HW_VLAN_CTAG_RX) > + set_bit(EMAC_STATUS_VLANSTRIP_EN, &adpt->status); > + else > + clear_bit(EMAC_STATUS_VLANSTRIP_EN, &adpt->status); What about TX vlan offload? [snip] > + > +/* Called when the network interface is made active */ > +static int emac_open(struct net_device *netdev) > +{ > + struct emac_adapter *adpt = netdev_priv(netdev); > + int ret; > + > + netif_carrier_off(netdev); That seems unnecessary here because your close/down function does that, and with PHYLIB you would get it set correctly anyway. [snip] > +/* PHY related IOCTLs */ > +static int emac_mii_ioctl(struct net_device *netdev, > + struct ifreq *ifr, int cmd) > +{ > + struct emac_adapter *adpt = netdev_priv(netdev); > + struct emac_phy *phy = &adpt->phy; > + struct mii_ioctl_data *data = if_mii(ifr); > + > + switch (cmd) { > + case SIOCGMIIPHY: > + data->phy_id = phy->addr; > + return 0; > + > + case SIOCGMIIREG: > + if (!capable(CAP_NET_ADMIN)) > + return -EPERM; > + > + if (data->reg_num & ~(0x1F)) > + return -EFAULT; > + > + if (data->phy_id >= PHY_MAX_ADDR) > + return -EFAULT; > + > + if (phy->external && data->phy_id != phy->addr) > + return -EFAULT; > + > + return emac_phy_read(adpt, data->phy_id, data->reg_num, > + &data->val_out); > + > + case SIOCSMIIREG: > + if (!capable(CAP_NET_ADMIN)) > + return -EPERM; > + > + if (data->reg_num & ~(0x1F)) > + return -EFAULT; > + > + if (data->phy_id >= PHY_MAX_ADDR) > + return -EFAULT; > + > + if (phy->external && data->phy_id != phy->addr) > + return -EFAULT; > + > + return emac_phy_write(adpt, data->phy_id, data->reg_num, > + data->val_in); > + default: > + return -EFAULT; > + } All of that can be eliminated with a PHYLIB implementation too. [snip] > +/* Provide network statistics info for the interface */ > +struct rtnl_link_stats64 *emac_get_stats64(struct net_device *netdev, > + struct rtnl_link_stats64 *net_stats) > +{ > + struct emac_adapter *adpt = netdev_priv(netdev); > + struct emac_stats *stats = &adpt->stats; > + u16 addr = REG_MAC_RX_STATUS_BIN; > + u64 *stats_itr = &adpt->stats.rx_ok; > + u32 val; > + > + while (addr <= REG_MAC_RX_STATUS_END) { > + val = readl_relaxed(adpt->base + addr); > + *stats_itr += val; > + ++stats_itr; > + addr += sizeof(u32); > + } There is no reader locking here, what happens if two applications read the statistics at the same time? [snip] > +/* Get the resources */ > +static int emac_probe_resources(struct platform_device *pdev, > + struct emac_adapter *adpt) > +{ > + struct net_device *netdev = adpt->netdev; > + struct device_node *node = pdev->dev.of_node; > + struct resource *res; > + const void *maddr; > + int ret = 0; > + int i; > + > + /* get time stamp enable flag */ > + adpt->timestamp_en = of_property_read_bool(node, "qcom,emac-tstamp-en"); > + > + /* get mac address */ > + maddr = of_get_mac_address(node); > + if (!maddr) > + return -ENODEV; No, generate a random one, continue, but warn, > + > + memcpy(adpt->mac_perm_addr, maddr, netdev->addr_len); > + > + ret = platform_get_irq_byname(pdev, EMAC_MAC_IRQ_RES); > + if (ret < 0) { > + netdev_err(adpt->netdev, > + "error: missing %s resource\n", EMAC_MAC_IRQ_RES); > + return ret; > + } > + adpt->irq.irq = ret; > + > + ret = emac_clks_get(pdev, adpt); > + if (ret) > + return ret; > + > + /* get register addresses */ > + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "base"); > + if (!res) { > + netdev_err(adpt->netdev, "error: missing 'base' resource\n"); > + ret = -ENXIO; > + goto err_reg_res; > + } > + > + adpt->base = devm_ioremap_resource(&pdev->dev, res); > + if (!adpt->base) { > + ret = -ENOMEM; > + goto err_reg_res; > + } > + > + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr"); > + if (!res) { > + netdev_err(adpt->netdev, "error: missing 'csr' resource\n"); > + ret = -ENXIO; > + goto err_reg_res; > + } No need to check that, devm_ioremap_resource() does it too. > + > + adpt->csr = devm_ioremap_resource(&pdev->dev, res); > + if (!adpt->csr) { > + ret = -ENOMEM; > + goto err_reg_res; > + } > + > + netdev->base_addr = (unsigned long)adpt->base; > + return 0; > + > +err_reg_res: > + for (i = 0; i < EMAC_CLK_CNT; i++) { > + if (adpt->clk[i]) { > + clk_put(adpt->clk[i]); > + adpt->clk[i] = NULL; > + } > + } > + > + return ret; > +} > + > +/* Release resources */ > +static void emac_release_resources(struct emac_adapter *adpt) > +{ > + int i; > + > + for (i = 0; i < EMAC_CLK_CNT; i++) > + if (adpt->clk[i]) { > + clk_put(adpt->clk[i]); > + adpt->clk[i] = NULL; > + } > +} > + > +/* Probe function */ > +static int emac_probe(struct platform_device *pdev) > +{ > + struct net_device *netdev; > + struct emac_adapter *adpt; > + struct emac_phy *phy; > + int ret = 0; > + u32 hw_ver; > + u32 extended_irq_mask = emac_irq_use_extended ? IMR_EXTENDED_MASK : > + IMR_NORMAL_MASK; > + > + netdev = alloc_etherdev(sizeof(struct emac_adapter)); > + if (!netdev) > + return -ENOMEM; There are references to multiple queues in the code, so why not alloc_etherdev_mq() here with the correct number of queues? > + > + dev_set_drvdata(&pdev->dev, netdev); > + SET_NETDEV_DEV(netdev, &pdev->dev); > + > + adpt = netdev_priv(netdev); > + adpt->netdev = netdev; > + phy = &adpt->phy; > + adpt->msg_enable = netif_msg_init(debug, EMAC_MSG_DEFAULT); > + > + dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)); Really, is not that supposed to run on ARM64 servers? -- Florian