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Date: Fri, 26 Apr 2013 13:56:52 +0200
From: Oliver Neukum <oneukum@...e.de>
To: Hayes Wang <hayeswang@...ltek.com>
Cc: gregkh@...uxfoundation.org, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
Realtek linux nic maintainers <nic_swsd@...ltek.com>
Subject: Re: [PATCH net-next] net/usb: new driver for RTL8152
On Friday 26 April 2013 16:45:48 Hayes Wang wrote:
> +static u16 r8152_mdio_read(struct r8152 *tp, u32 reg_addr)
> +{
> + u32 ocp_data;
> + int i;
> +
> + ocp_data = (reg_addr & 0x1f) << 16;
> + ocp_write_dword(tp, MCU_TYPE_PLA, PLA_PHYAR, ocp_data);
> +
> + for (i = 20; i > 0; i--) {
> + udelay(25);
> + ocp_data = ocp_read_dword(tp, MCU_TYPE_PLA, PLA_PHYAR);
> + if (ocp_data & PHYAR_FLAG)
> + break;
> + }
> + udelay(20);
> +
> + return (u16)(ocp_data & 0xffff);
> +}
Unfortunately this can fail, as it is physical IO and you throw away errors.
> +static int read_mii_word(struct net_device *netdev, int phy_id, int reg)
> +{
> + struct r8152 *tp = netdev_priv(netdev);
> +
> + if (phy_id != R8152_PHY_ID)
> + return -1;
> +
> + return r8152_mdio_read(tp, reg);
> +}
> +
> +static
> +void write_mii_word(struct net_device *netdev, int phy_id, int reg, int val)
> +{
> + struct r8152 *tp = netdev_priv(netdev);
> +
> + if (phy_id != R8152_PHY_ID)
> + return;
> +
> + r8152_mdio_write(tp, reg, val);
> +}
> +
> +static void ocp_reg_write(struct r8152 *tp, u16 addr, u16 data)
> +{
> + u16 ocp_base, ocp_index;
> +
> + ocp_base = addr & 0xf000;
> + if (ocp_base != tp->ocp_base) {
> + ocp_write_word(tp, MCU_TYPE_PLA, PLA_OCP_GPHY_BASE, ocp_base);
> + tp->ocp_base = ocp_base;
> + }
> +
> + ocp_index = (addr & 0x0fff) | 0xb000;
> + ocp_write_word(tp, MCU_TYPE_PLA, ocp_index, data);
> +}
> +
> +static inline void set_ethernet_addr(struct r8152 *tp)
> +{
> + struct net_device *dev = tp->netdev;
> + u8 node_id[8] = {0};
> +
> + if (pla_ocp_read(tp, PLA_IDR, sizeof(node_id), node_id) < 0)
DMA coherency rules. No buffers on the stack.
> + netif_notice(tp, probe, dev, "inet addr fail\n");
> + else {
> + memcpy(dev->dev_addr, node_id, sizeof(node_id));
> + memcpy(dev->perm_addr, dev->dev_addr, dev->addr_len);
> + }
> +}
> +static void _rtl8152_set_rx_mode(struct net_device *netdev)
> +{
> + struct r8152 *tp = netdev_priv(netdev);
> + u32 tmp, mc_filter[2]; /* Multicast hash filter */
> + u32 ocp_data;
> +
> + clear_bit(RTL8152_SET_RX_MODE, &tp->flags);
> + netif_stop_queue(netdev);
> + ocp_data = ocp_read_dword(tp, MCU_TYPE_PLA, PLA_RCR);
> + ocp_data &= ~RCR_ACPT_ALL;
> + ocp_data |= RCR_AB | RCR_APM;
> +
> + if (netdev->flags & IFF_PROMISC) {
> + /* Unconditionally log net taps. */
> + netif_notice(tp, link, netdev, "Promiscuous mode enabled\n");
> + ocp_data |= RCR_AM | RCR_AAP;
> + mc_filter[1] = mc_filter[0] = 0xffffffff;
> + } else if ((netdev_mc_count(netdev) > multicast_filter_limit) ||
> + (netdev->flags & IFF_ALLMULTI)) {
> + /* Too many to filter perfectly -- accept all multicasts. */
> + ocp_data |= RCR_AM;
> + mc_filter[1] = mc_filter[0] = 0xffffffff;
> + } else {
> + struct netdev_hw_addr *ha;
> +
> + mc_filter[1] = mc_filter[0] = 0;
> + netdev_for_each_mc_addr(ha, netdev) {
> + int bit_nr = ether_crc(ETH_ALEN, ha->addr) >> 26;
> + mc_filter[bit_nr >> 5] |= 1 << (bit_nr & 31);
> + ocp_data |= RCR_AM;
> + }
> + }
> +
> + tmp = mc_filter[0];
> + mc_filter[0] = __cpu_to_le32(swab32(mc_filter[1]));
> + mc_filter[1] = __cpu_to_le32(swab32(tmp));
> +
> + pla_ocp_write(tp, PLA_MAR, BYTE_EN_DWORD, sizeof(mc_filter), mc_filter);
This looks like a violation of the DMA coherency rules.
You cannot use buffers on the stack.
> + ocp_write_dword(tp, MCU_TYPE_PLA, PLA_RCR, ocp_data);
> + netif_wake_queue(netdev);
> +}
> +
> +static void rtl_work_func_t(struct work_struct *work)
> +{
> + struct r8152 *tp = container_of(work, struct r8152, schedule.work);
> +
> + if (!netif_running(tp->netdev))
> + goto out1;
> +
> + if (test_bit(RTL8152_UNPLUG, &tp->flags))
> + goto out1;
> +
> + set_carrier(tp);
> +
> + if (test_bit(RTL8152_SET_RX_MODE, &tp->flags))
> + _rtl8152_set_rx_mode(tp->netdev);
> +
> + schedule_delayed_work(&tp->schedule, HZ);
Why does this need to run permanently?
> +
> +out1:
> + return;
> +}
> +
> +static int rtl8152_open(struct net_device *netdev)
> +{
> + struct r8152 *tp = netdev_priv(netdev);
> + int res = 0;
> +
> + tp->speed = rtl8152_get_speed(tp);
> + if (tp->speed & LINK_STATUS) {
> + res = rtl8152_enable(tp);
> + netif_carrier_on(netdev);
And you leave it on in the error case?
> + } else {
> + netif_stop_queue(netdev);
> + netif_carrier_off(netdev);
> + }
> +
> + if (res) {
> + if (res == -ENODEV)
> + netif_device_detach(tp->netdev);
> +
> + netif_warn(tp, rx_err, netdev,
> + "rx_urb submit failed: %d\n", res);
> + return res;
> + }
> +
> + rtl8152_set_speed(tp, AUTONEG_ENABLE, SPEED_100, DUPLEX_FULL);
> + netif_start_queue(netdev);
> + schedule_delayed_work(&tp->schedule, 0);
> +
> + return res;
> +}
> +
> +static int rtl8152_close(struct net_device *netdev)
> +{
> + struct r8152 *tp = netdev_priv(netdev);
> + int res = 0;
> +
> + cancel_delayed_work_sync(&tp->schedule);
Looks like a race. What makes sure the work isn't rescheduled?
> + netif_stop_queue(netdev);
> + rtl8152_disable(tp);
> +
> + return res;
> +}
> +static int rtl8152_suspend(struct usb_interface *intf, pm_message_t message)
> +{
> + struct r8152 *tp = usb_get_intfdata(intf);
> +
> + netif_device_detach(tp->netdev);
> +
> + if (netif_running(tp->netdev))
> + cancel_delayed_work_sync(&tp->schedule);
This looks like a race. What makes sure that the work isn't rescheduled?
> +
> + rtl8152_down(tp);
> +
> + return 0;
> +}
> +
> +static int rtl8152_resume(struct usb_interface *intf)
> +{
> + struct r8152 *tp = usb_get_intfdata(intf);
> +
> + r8152b_init(tp);
> + netif_device_attach(tp->netdev);
> + if (netif_running(tp->netdev)) {
> + rtl8152_enable(tp);
> + rtl8152_set_speed(tp, AUTONEG_ENABLE, SPEED_100, DUPLEX_FULL);
But this may not be the speed that was selected before the device
was suspended.
> + set_bit(RTL8152_SET_RX_MODE, &tp->flags);
> + schedule_delayed_work(&tp->schedule, 0);
> + }
> +
> + return 0;
> +}
> +static void rtl8152_unload(struct r8152 *tp)
> +{
> + u32 ocp_data;
> +
> + if (tp->version != RTL_VER_01) {
> + ocp_data = ocp_read_word(tp, MCU_TYPE_USB, USB_UPS_CTRL);
> + ocp_data |= POWER_CUT;
> + ocp_write_word(tp, MCU_TYPE_USB, USB_UPS_CTRL, ocp_data);
> + }
> +
> + ocp_data = ocp_read_word(tp, MCU_TYPE_USB, USB_PM_CTRL_STATUS);
> + ocp_data &= ~RWSUME_INDICATE;
> + ocp_write_word(tp, MCU_TYPE_USB, USB_PM_CTRL_STATUS, ocp_data);
> +}
> +
> +static void rtl8152_disconnect(struct usb_interface *intf)
> +{
> + struct r8152 *tp = usb_get_intfdata(intf);
> +
> + usb_set_intfdata(intf, NULL);
> + if (tp) {
> + set_bit(RTL8152_UNPLUG, &tp->flags);
> + tasklet_kill(&tp->tl);
This looks like a race condition. What prevents the tasklet from being
scheduled here in case of a soft disconnect?
> + unregister_netdev(tp->netdev);
> + rtl8152_unload(tp);
> + free_all_urbs(tp);
> + if (tp->rx_skb)
> + dev_kfree_skb(tp->rx_skb);
> + free_netdev(tp->netdev);
> + }
> +}
Regards
Oliver
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