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/****************************************************************************
* Driver for Solarflare Solarstorm network controllers and boards
* Copyright 2005-2006 Fen Systems Ltd.
* Copyright 2005-2011 Solarflare Communications Inc.
*
* 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, incorporated herein by reference.
*/
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/slab.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/prefetch.h>
#include <linux/moduleparam.h>
#include <net/ip.h>
#include <net/checksum.h>
#include "net_driver.h"
#include "efx.h"
#include "nic.h"
#include "selftest.h"
#include "workarounds.h"
/* Number of RX descriptors pushed at once. */
#define EFX_RX_BATCH 8
/* Maximum size of a buffer sharing a page */
#define EFX_RX_HALF_PAGE ((PAGE_SIZE >> 1) - sizeof(struct efx_rx_page_state))
/* Size of buffer allocated for skb header area. */
#define EFX_SKB_HEADERS 64u
/*
* rx_alloc_method - RX buffer allocation method
*
* This driver supports two methods for allocating and using RX buffers:
* each RX buffer may be backed by an skb or by an order-n page.
*
* When GRO is in use then the second method has a lower overhead,
* since we don't have to allocate then free skbs on reassembled frames.
*
* Values:
* - RX_ALLOC_METHOD_AUTO = 0
* - RX_ALLOC_METHOD_SKB = 1
* - RX_ALLOC_METHOD_PAGE = 2
*
* The heuristic for %RX_ALLOC_METHOD_AUTO is a simple hysteresis count
* controlled by the parameters below.
*
* - Since pushing and popping descriptors are separated by the rx_queue
* size, so the watermarks should be ~rxd_size.
* - The performance win by using page-based allocation for GRO is less
* than the performance hit of using page-based allocation of non-GRO,
* so the watermarks should reflect this.
*
* Per channel we maintain a single variable, updated by each channel:
*
* rx_alloc_level += (gro_performed ? RX_ALLOC_FACTOR_GRO :
* RX_ALLOC_FACTOR_SKB)
* Per NAPI poll interval, we constrain rx_alloc_level to 0..MAX (which
* limits the hysteresis), and update the allocation strategy:
*
* rx_alloc_method = (rx_alloc_level > RX_ALLOC_LEVEL_GRO ?
* RX_ALLOC_METHOD_PAGE : RX_ALLOC_METHOD_SKB)
*/
static int rx_alloc_method = RX_ALLOC_METHOD_AUTO;
#define RX_ALLOC_LEVEL_GRO 0x2000
#define RX_ALLOC_LEVEL_MAX 0x3000
#define RX_ALLOC_FACTOR_GRO 1
#define RX_ALLOC_FACTOR_SKB (-2)
/* This is the percentage fill level below which new RX descriptors
* will be added to the RX descriptor ring.
*/
static unsigned int rx_refill_threshold;
/*
* RX maximum head room required.
*
* This must be at least 1 to prevent overflow and at least 2 to allow
* pipelined receives.
*/
#define EFX_RXD_HEAD_ROOM 2
/* Offset of ethernet header within page */
static inline unsigned int efx_rx_buf_offset(struct efx_nic *efx,
struct efx_rx_buffer *buf)
{
/* Offset is always within one page, so we don't need to consider
* the page order.
*/
return ((unsigned int) buf->dma_addr & (PAGE_SIZE - 1)) +
efx->type->rx_buffer_hash_size;
}
static inline unsigned int efx_rx_buf_size(struct efx_nic *efx)
{
return PAGE_SIZE << efx->rx_buffer_order;
}
static u8 *efx_rx_buf_eh(struct efx_nic *efx, struct efx_rx_buffer *buf)
{
if (buf->flags & EFX_RX_BUF_PAGE)
return page_address(buf->u.page) + efx_rx_buf_offset(efx, buf);
else
return (u8 *)buf->u.skb->data + efx->type->rx_buffer_hash_size;
}
static inline u32 efx_rx_buf_hash(const u8 *eh)
{
/* The ethernet header is always directly after any hash. */
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) || NET_IP_ALIGN % 4 == 0
return __le32_to_cpup((const __le32 *)(eh - 4));
#else
const u8 *data = eh - 4;
return (u32)data[0] |
(u32)data[1] << 8 |
(u32)data[2] << 16 |
(u32)data[3] << 24;
#endif
}
/**
* efx_init_rx_buffers_skb - create EFX_RX_BATCH skb-based RX buffers
*
* @rx_queue: Efx RX queue
*
* This allocates EFX_RX_BATCH skbs, maps them for DMA, and populates a
* struct efx_rx_buffer for each one. Return a negative error code or 0
* on success. May fail having only inserted fewer than EFX_RX_BATCH
* buffers.
*/
static int efx_init_rx_buffers_skb(struct efx_rx_queue *rx_queue)
{
struct efx_nic *efx = rx_queue->efx;
struct net_device *net_dev = efx->net_dev;
struct efx_rx_buffer *rx_buf;
struct sk_buff *skb;
int skb_len = efx->rx_buffer_len;
unsigned index, count;
for (count = 0; count < EFX_RX_BATCH; ++count) {
index = rx_queue->added_count & rx_queue->ptr_mask;
rx_buf = efx_rx_buffer(rx_queue, index);
rx_buf->u.skb = skb = netdev_alloc_skb(net_dev, skb_len);
if (unlikely(!skb))
return -ENOMEM;
/* Adjust the SKB for padding */
skb_reserve(skb, NET_IP_ALIGN);
rx_buf->len = skb_len - NET_IP_ALIGN;
rx_buf->flags = 0;
rx_buf->dma_addr = pci_map_single(efx->pci_dev,
skb->data, rx_buf->len,
PCI_DMA_FROMDEVICE);
if (unlikely(pci_dma_mapping_error(efx->pci_dev,
rx_buf->dma_addr))) {
dev_kfree_skb_any(skb);
rx_buf->u.skb = NULL;
return -EIO;
}
++rx_queue->added_count;
++rx_queue->alloc_skb_count;
}
return 0;
}
/**
* efx_init_rx_buffers_page - create EFX_RX_BATCH page-based RX buffers
*
* @rx_queue: Efx RX queue
*
* This allocates memory for EFX_RX_BATCH receive buffers, maps them for DMA,
* and populates struct efx_rx_buffers for each one. Return a negative error
* code or 0 on success. If a single page can be split between two buffers,
* then the page will either be inserted fully, or not at at all.
*/
static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue)
{
struct efx_nic *efx = rx_queue->efx;
struct efx_rx_buffer *rx_buf;
struct page *page;
void *page_addr;
struct efx_rx_page_state *state;
dma_addr_t dma_addr;
unsigned index, count;
/* We can split a page between two buffers */
BUILD_BUG_ON(EFX_RX_BATCH & 1);
for (count = 0; count < EFX_RX_BATCH; ++count) {
page = alloc_pages(__GFP_COLD | __GFP_COMP | GFP_ATOMIC,
efx->rx_buffer_order);
if (unlikely(page == NULL))
return -ENOMEM;
dma_addr = pci_map_page(efx->pci_dev, page, 0,
efx_rx_buf_size(efx),
PCI_DMA_FROMDEVICE);
if (unlikely(pci_dma_mapping_error(efx->pci_dev, dma_addr))) {
__free_pages(page, efx->rx_buffer_order);
return -EIO;
}
page_addr = page_address(page);
state = page_addr;
state->refcnt = 0;
state->dma_addr = dma_addr;
page_addr += sizeof(struct efx_rx_page_state);
dma_addr += sizeof(struct efx_rx_page_state);
split:
index = rx_queue->added_count & rx_queue->ptr_mask;
rx_buf = efx_rx_buffer(rx_queue, index);
rx_buf->dma_addr = dma_addr + EFX_PAGE_IP_ALIGN;
rx_buf->u.page = page;
rx_buf->len = efx->rx_buffer_len -
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