diff options
| -rw-r--r-- | drivers/net/ethernet/oa_tc6.c | 258 |
1 files changed, 189 insertions, 69 deletions
diff --git a/drivers/net/ethernet/oa_tc6.c b/drivers/net/ethernet/oa_tc6.c index 417c15d1ff42..6fcc5f561d56 100644 --- a/drivers/net/ethernet/oa_tc6.c +++ b/drivers/net/ethernet/oa_tc6.c @@ -83,7 +83,7 @@ struct oa_tc6 { u16 spi_data_tx_buf_offset; u16 tx_credits; u8 rx_chunks_available; - bool rx_buf_overflow; + bool wait_until_start_valid; bool int_flag; bool disable_traffic; bool prot_ctrl; @@ -455,7 +455,7 @@ static int oa_tc6_mdiobus_read(struct mii_bus *bus, int addr, int regnum) { struct oa_tc6 *tc6 = bus->priv; u32 regval; - bool ret; + int ret; ret = oa_tc6_read_register(tc6, OA_TC6_PHY_STD_REG_ADDR_BASE | (regnum & OA_TC6_PHY_STD_REG_ADDR_MASK), @@ -693,6 +693,26 @@ static int oa_tc6_enable_data_transfer(struct oa_tc6 *tc6) return oa_tc6_write_register(tc6, OA_TC6_REG_CONFIG0, value); } +/* Called when a frame that is meant to be transmitted, is dropped. */ +static void oa_tc6_drop_tx_skb(struct oa_tc6 *tc6, struct sk_buff *skb) +{ + if (skb) { + tc6->netdev->stats.tx_dropped++; + dev_kfree_skb_any(skb); + } +} + +static struct sk_buff *oa_tc6_detach_waiting_tx_skb(struct oa_tc6 *tc6) +{ + struct sk_buff *skb; + + lockdep_assert_held(&tc6->tx_skb_lock); + skb = tc6->waiting_tx_skb; + tc6->waiting_tx_skb = NULL; + + return skb; +} + static void oa_tc6_cleanup_ongoing_rx_skb(struct oa_tc6 *tc6) { if (tc6->rx_skb) { @@ -704,29 +724,39 @@ static void oa_tc6_cleanup_ongoing_rx_skb(struct oa_tc6 *tc6) static void oa_tc6_cleanup_ongoing_tx_skb(struct oa_tc6 *tc6) { - if (tc6->ongoing_tx_skb) { - tc6->netdev->stats.tx_dropped++; - kfree_skb(tc6->ongoing_tx_skb); - tc6->ongoing_tx_skb = NULL; - } + oa_tc6_drop_tx_skb(tc6, tc6->ongoing_tx_skb); + tc6->ongoing_tx_skb = NULL; } static void oa_tc6_cleanup_waiting_tx_skb(struct oa_tc6 *tc6) { - if (tc6->waiting_tx_skb) { - tc6->netdev->stats.tx_dropped++; - kfree_skb(tc6->waiting_tx_skb); - tc6->waiting_tx_skb = NULL; - } + struct sk_buff *skb; + + spin_lock_bh(&tc6->tx_skb_lock); + skb = oa_tc6_detach_waiting_tx_skb(tc6); + spin_unlock_bh(&tc6->tx_skb_lock); + + oa_tc6_drop_tx_skb(tc6, skb); } -static void oa_tc6_free_pending_skbs(struct oa_tc6 *tc6) +static void oa_tc6_free_ongoing_skbs(struct oa_tc6 *tc6) { oa_tc6_cleanup_ongoing_tx_skb(tc6); oa_tc6_cleanup_ongoing_rx_skb(tc6); +} + +static void oa_tc6_free_pending_skbs(struct oa_tc6 *tc6) +{ + oa_tc6_free_ongoing_skbs(tc6); oa_tc6_cleanup_waiting_tx_skb(tc6); } +static void oa_tc6_look_for_new_frame(struct oa_tc6 *tc6) +{ + tc6->wait_until_start_valid = true; + oa_tc6_cleanup_ongoing_rx_skb(tc6); +} + /* If the failure is at SPI interface level, masking and clearing * the interrupt of the device won't work. Since SPI interrupt is * disabled, it should stop the repeated interrupts. @@ -734,9 +764,19 @@ static void oa_tc6_free_pending_skbs(struct oa_tc6 *tc6) static void oa_tc6_disable_traffic(struct oa_tc6 *tc6) { u32 regval = OA_TC6_INT_MASK0_ALL_INTERRUPTS; + struct sk_buff *skb; + spin_lock_bh(&tc6->tx_skb_lock); tc6->disable_traffic = true; - oa_tc6_free_pending_skbs(tc6); + skb = oa_tc6_detach_waiting_tx_skb(tc6); + spin_unlock_bh(&tc6->tx_skb_lock); + + /* disable_traffic, when set, is a point of no return to + * working state. Keeping the TX queues disabled. + */ + netif_tx_disable(tc6->netdev); + oa_tc6_drop_tx_skb(tc6, skb); + oa_tc6_free_ongoing_skbs(tc6); oa_tc6_write_register(tc6, OA_TC6_REG_INT_MASK0, regval); oa_tc6_read_register(tc6, OA_TC6_REG_STATUS0, ®val); oa_tc6_write_register(tc6, OA_TC6_REG_STATUS0, regval); @@ -755,6 +795,13 @@ static int oa_tc6_process_extended_status(struct oa_tc6 *tc6) return ret; } + /* This function is called for each chunk received in a given SPI + * transaction. In case, extended status bit is set in more than + * one chunk, skip the write, if status0 is already cleared. + */ + if (!value) + return 0; + /* Clear the error interrupts status */ ret = oa_tc6_write_register(tc6, OA_TC6_REG_STATUS0, value); if (ret) { @@ -764,8 +811,7 @@ static int oa_tc6_process_extended_status(struct oa_tc6 *tc6) } if (FIELD_GET(OA_TC6_STATUS0_RX_BUFFER_OVERFLOW_ERROR, value)) { - tc6->rx_buf_overflow = true; - oa_tc6_cleanup_ongoing_rx_skb(tc6); + oa_tc6_look_for_new_frame(tc6); net_err_ratelimited("%s: Receive buffer overflow error\n", tc6->netdev->name); return -EAGAIN; @@ -791,6 +837,8 @@ static int oa_tc6_process_extended_status(struct oa_tc6 *tc6) static int oa_tc6_process_rx_chunk_footer(struct oa_tc6 *tc6, u32 footer) { + int ret = 0; + /* Process rx chunk footer for the following, * 1. tx credits * 2. errors if any from MAC-PHY @@ -801,9 +849,11 @@ static int oa_tc6_process_rx_chunk_footer(struct oa_tc6 *tc6, u32 footer) footer); if (FIELD_GET(OA_TC6_DATA_FOOTER_EXTENDED_STS, footer)) { - int ret = oa_tc6_process_extended_status(tc6); - - if (ret) + ret = oa_tc6_process_extended_status(tc6); + /* EAGAIN error is recoverable. Move on to check + * HEADER and SYNC errors before returning. + */ + if (ret && ret != -EAGAIN) return ret; } @@ -821,7 +871,7 @@ static int oa_tc6_process_rx_chunk_footer(struct oa_tc6 *tc6, u32 footer) return -ENODEV; } - return 0; + return ret; } static void oa_tc6_submit_rx_skb(struct oa_tc6 *tc6) @@ -846,13 +896,35 @@ static void oa_tc6_submit_rx_skb(struct oa_tc6 *tc6) tc6->rx_skb = NULL; } -static void oa_tc6_update_rx_skb(struct oa_tc6 *tc6, u8 *payload, u8 length) +/* On oversubscribed traffic condition, particularly with overwhelming rx + * buffer overflow errors, there could be data chunk loss. If tail + length + * goes beyond end pointer, that is an indication that the data chunk with + * end_valid bit is lost. Time to look for a data chunk with start_valid bit. + * + * If rx_skb is NULL, it is time to start looking for data chunk with + * start_bit. + */ +static int oa_tc6_update_rx_skb(struct oa_tc6 *tc6, u8 *payload, u8 length) { + if (!tc6->rx_skb || + skb_tailroom(tc6->rx_skb) < length) { + oa_tc6_look_for_new_frame(tc6); + return -EAGAIN; + } + memcpy(skb_put(tc6->rx_skb, length), payload, length); + return 0; } +/* On overwhelming rx buffer overflow errors, due to data chunk loss, it is + * possible that we get two data chunks with start_valid bit set, without + * end_valid bit set in between. In this case, rx_skb would have a valid + * buffer pointer. We should release, if a valid pointer is found before + * allocating a new one. + */ static int oa_tc6_allocate_rx_skb(struct oa_tc6 *tc6) { + oa_tc6_cleanup_ongoing_rx_skb(tc6); tc6->rx_skb = netdev_alloc_skb_ip_align(tc6->netdev, tc6->netdev->mtu + ETH_HLEN + ETH_FCS_LEN); if (!tc6->rx_skb) { @@ -872,7 +944,9 @@ static int oa_tc6_prcs_complete_rx_frame(struct oa_tc6 *tc6, u8 *payload, if (ret) return ret; - oa_tc6_update_rx_skb(tc6, payload, size); + ret = oa_tc6_update_rx_skb(tc6, payload, size); + if (ret) + return ret; oa_tc6_submit_rx_skb(tc6); @@ -887,22 +961,24 @@ static int oa_tc6_prcs_rx_frame_start(struct oa_tc6 *tc6, u8 *payload, u16 size) if (ret) return ret; - oa_tc6_update_rx_skb(tc6, payload, size); - - return 0; + return oa_tc6_update_rx_skb(tc6, payload, size); } -static void oa_tc6_prcs_rx_frame_end(struct oa_tc6 *tc6, u8 *payload, u16 size) +static int oa_tc6_prcs_rx_frame_end(struct oa_tc6 *tc6, u8 *payload, u16 size) { - oa_tc6_update_rx_skb(tc6, payload, size); + int ret; - oa_tc6_submit_rx_skb(tc6); + ret = oa_tc6_update_rx_skb(tc6, payload, size); + if (!ret) + oa_tc6_submit_rx_skb(tc6); + return ret; } -static void oa_tc6_prcs_ongoing_rx_frame(struct oa_tc6 *tc6, u8 *payload, - u32 footer) +static int oa_tc6_prcs_ongoing_rx_frame(struct oa_tc6 *tc6, u8 *payload, + u32 footer) { - oa_tc6_update_rx_skb(tc6, payload, OA_TC6_CHUNK_PAYLOAD_SIZE); + return oa_tc6_update_rx_skb(tc6, payload, + OA_TC6_CHUNK_PAYLOAD_SIZE); } static int oa_tc6_prcs_rx_chunk_payload(struct oa_tc6 *tc6, u8 *data, @@ -917,10 +993,10 @@ static int oa_tc6_prcs_rx_chunk_payload(struct oa_tc6 *tc6, u8 *data, u16 size; /* Restart the new rx frame after receiving rx buffer overflow error */ - if (start_valid && tc6->rx_buf_overflow) - tc6->rx_buf_overflow = false; + if (start_valid && tc6->wait_until_start_valid) + tc6->wait_until_start_valid = false; - if (tc6->rx_buf_overflow) + if (tc6->wait_until_start_valid) return 0; /* Process the chunk with complete rx frame */ @@ -942,8 +1018,7 @@ static int oa_tc6_prcs_rx_chunk_payload(struct oa_tc6 *tc6, u8 *data, /* Process the chunk with only rx frame end */ if (end_valid && !start_valid) { size = end_byte_offset + 1; - oa_tc6_prcs_rx_frame_end(tc6, data, size); - return 0; + return oa_tc6_prcs_rx_frame_end(tc6, data, size); } /* Process the chunk with previous rx frame end and next rx frame @@ -957,6 +1032,15 @@ static int oa_tc6_prcs_rx_chunk_payload(struct oa_tc6 *tc6, u8 *data, if (tc6->rx_skb) { size = end_byte_offset + 1; oa_tc6_prcs_rx_frame_end(tc6, data, size); + + /* Return value from oa_tc6_prcs_rx_frame_end is not + * checked. If it returned an error, it is to make + * the code to look for new frame. At this stage, + * code below is going to process a new frame. So, + * error condition is set to false, in case it is + * set before proceeding. + */ + tc6->wait_until_start_valid = false; } size = OA_TC6_CHUNK_PAYLOAD_SIZE - start_byte_offset; return oa_tc6_prcs_rx_frame_start(tc6, @@ -965,9 +1049,7 @@ static int oa_tc6_prcs_rx_chunk_payload(struct oa_tc6 *tc6, u8 *data, } /* Process the chunk with ongoing rx frame data */ - oa_tc6_prcs_ongoing_rx_frame(tc6, data, footer); - - return 0; + return oa_tc6_prcs_ongoing_rx_frame(tc6, data, footer); } static u32 oa_tc6_get_rx_chunk_footer(struct oa_tc6 *tc6, u16 footer_offset) @@ -983,8 +1065,9 @@ static u32 oa_tc6_get_rx_chunk_footer(struct oa_tc6 *tc6, u16 footer_offset) static int oa_tc6_process_spi_data_rx_buf(struct oa_tc6 *tc6, u16 length) { u16 no_of_rx_chunks = length / OA_TC6_CHUNK_SIZE; + bool retry = false; + int ret = 0; u32 footer; - int ret; /* All the rx chunks in the receive SPI data buffer are examined here */ for (int i = 0; i < no_of_rx_chunks; i++) { @@ -993,8 +1076,11 @@ static int oa_tc6_process_spi_data_rx_buf(struct oa_tc6 *tc6, u16 length) OA_TC6_CHUNK_PAYLOAD_SIZE); ret = oa_tc6_process_rx_chunk_footer(tc6, footer); - if (ret) - return ret; + if (ret) { + if (ret != -EAGAIN) + return ret; + retry = true; + } /* If there is a data valid chunks then process it for the * information needed to determine the validity and the location @@ -1006,12 +1092,35 @@ static int oa_tc6_process_spi_data_rx_buf(struct oa_tc6 *tc6, u16 length) ret = oa_tc6_prcs_rx_chunk_payload(tc6, payload, footer); - if (ret) - return ret; + if (ret) { + if (ret != -ENOMEM && ret != -EAGAIN) + return ret; + retry = true; + } } } - return 0; + /* Not bailing out on recoverable error codes, -EAGAIN and + * -ENOMEM. If subsequent loop iterations, if any, succeeds, + * error code would be overwritten. retry flag helps to + * make the caller to continue and retry. Since recovery + * action for -ENOMEM and -EAGAIN are same, we are returning + * one of the error codes, that is -EAGAIN. + * + * Successful recovery depends on how small the frames are, + * how many chunks, among the received chunks triggered the + * error, whether data is intact even with error conditions. + * As a result, there is no single, best method to recover + * most data when error conditions hit. We do our best by + * processing all the chunks with good "footer header" and + * "data valid" bit set. + */ + if (retry) { + ret = -EAGAIN; + oa_tc6_look_for_new_frame(tc6); + } + + return ret; } static __be32 oa_tc6_prepare_data_header(bool data_valid, bool start_valid, @@ -1173,12 +1282,9 @@ static int oa_tc6_try_spi_transfer(struct oa_tc6 *tc6) } ret = oa_tc6_process_spi_data_rx_buf(tc6, spi_len); - if (ret) { - if (ret == -EAGAIN) - continue; - oa_tc6_cleanup_ongoing_tx_skb(tc6); - oa_tc6_cleanup_ongoing_rx_skb(tc6); + if (ret && ret != -EAGAIN) { + oa_tc6_free_ongoing_skbs(tc6); netdev_err(tc6->netdev, "Device error: %d\n", ret); return ret; } @@ -1200,15 +1306,20 @@ static irqreturn_t oa_tc6_macphy_threaded_irq(int irq, void *data) * no need to attempt spi transfer, once it fails. Pending skbs * are already freed. */ - if (!tc6->disable_traffic) { - while (tc6->int_flag || - (tc6->waiting_tx_skb && tc6->tx_credits)) { - ret = oa_tc6_try_spi_transfer(tc6); - if (ret) { - disable_irq_nosync(tc6->spi->irq); - oa_tc6_disable_traffic(tc6); - break; - } + spin_lock_bh(&tc6->tx_skb_lock); + if (tc6->disable_traffic) { + spin_unlock_bh(&tc6->tx_skb_lock); + return IRQ_HANDLED; + } + spin_unlock_bh(&tc6->tx_skb_lock); + + while (tc6->int_flag || + (tc6->waiting_tx_skb && tc6->tx_credits)) { + ret = oa_tc6_try_spi_transfer(tc6); + if (ret) { + disable_irq_nosync(tc6->spi->irq); + oa_tc6_disable_traffic(tc6); + break; } } @@ -1287,23 +1398,30 @@ EXPORT_SYMBOL_GPL(oa_tc6_zero_align_receive_frame_enable); * @tc6: oa_tc6 struct. * @skb: socket buffer in which the ethernet frame is stored. * - * Return: NETDEV_TX_OK if the transmit ethernet frame skb added in the tx_skb_q - * otherwise returns NETDEV_TX_BUSY. + * Return: NETDEV_TX_OK either on successful queueing of the packet for + * transmission, or on packet getting dropped. Packet can be dropped due to + * failure in linearizing the buffer or disable_traffic is set due to + * earlier fatal error. Returns NETDEV_TX_BUSY when there is no room + * to queue the packet. */ netdev_tx_t oa_tc6_start_xmit(struct oa_tc6 *tc6, struct sk_buff *skb) { - if (tc6->disable_traffic || tc6->waiting_tx_skb) { - netif_stop_queue(tc6->netdev); - return NETDEV_TX_BUSY; - } - if (skb_linearize(skb)) { - dev_kfree_skb_any(skb); - tc6->netdev->stats.tx_dropped++; + oa_tc6_drop_tx_skb(tc6, skb); return NETDEV_TX_OK; } spin_lock_bh(&tc6->tx_skb_lock); + if (tc6->waiting_tx_skb) { + netif_stop_queue(tc6->netdev); + spin_unlock_bh(&tc6->tx_skb_lock); + return NETDEV_TX_BUSY; + } + if (tc6->disable_traffic) { + spin_unlock_bh(&tc6->tx_skb_lock); + oa_tc6_drop_tx_skb(tc6, skb); + return NETDEV_TX_OK; + } tc6->waiting_tx_skb = skb; spin_unlock_bh(&tc6->tx_skb_lock); @@ -1462,8 +1580,10 @@ EXPORT_SYMBOL_GPL(oa_tc6_init); */ void oa_tc6_exit(struct oa_tc6 *tc6) { - tc6->disable_traffic = true; disable_irq(tc6->spi->irq); + spin_lock_bh(&tc6->tx_skb_lock); + tc6->disable_traffic = true; + spin_unlock_bh(&tc6->tx_skb_lock); oa_tc6_phy_exit(tc6); oa_tc6_free_pending_skbs(tc6); } |