/******************************************************************************
*
* Copyright(c) 2003 - 2011 Intel Corporation. All rights reserved.
*
* Portions of this file are derived from the ipw3945 project, as well
* as portions of the ieee80211 subsystem header files.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2 of the GNU General Public License 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.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
*
* The full GNU General Public License is included in this distribution in the
* file called LICENSE.
*
* Contact Information:
* Intel Linux Wireless <ilw@linux.intel.com>
* Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
*
*****************************************************************************/
#include <linux/etherdevice.h>
#include <linux/slab.h>
#include <net/mac80211.h>
#include <asm/unaligned.h>
#include "iwl-eeprom.h"
#include "iwl-dev.h"
#include "iwl-core.h"
#include "iwl-sta.h"
#include "iwl-io.h"
#include "iwl-helpers.h"
/************************** RX-FUNCTIONS ****************************/
/*
* Rx theory of operation
*
* Driver allocates a circular buffer of Receive Buffer Descriptors (RBDs),
* each of which point to Receive Buffers to be filled by the NIC. These get
* used not only for Rx frames, but for any command response or notification
* from the NIC. The driver and NIC manage the Rx buffers by means
* of indexes into the circular buffer.
*
* Rx Queue Indexes
* The host/firmware share two index registers for managing the Rx buffers.
*
* The READ index maps to the first position that the firmware may be writing
* to -- the driver can read up to (but not including) this position and get
* good data.
* The READ index is managed by the firmware once the card is enabled.
*
* The WRITE index maps to the last position the driver has read from -- the
* position preceding WRITE is the last slot the firmware can place a packet.
*
* The queue is empty (no good data) if WRITE = READ - 1, and is full if
* WRITE = READ.
*
* During initialization, the host sets up the READ queue position to the first
* INDEX position, and WRITE to the last (READ - 1 wrapped)
*
* When the firmware places a packet in a buffer, it will advance the READ index
* and fire the RX interrupt. The driver can then query the READ index and
* process as many packets as possible, moving the WRITE index forward as it
* resets the Rx queue buffers with new memory.
*
* The management in the driver is as follows:
* + A list of pre-allocated SKBs is stored in iwl->rxq->rx_free. When
* iwl->rxq->free_count drops to or below RX_LOW_WATERMARK, work is scheduled
* to replenish the iwl->rxq->rx_free.
* + In il_rx_replenish (scheduled) if 'processed' != 'read' then the
* iwl->rxq is replenished and the READ INDEX is updated (updating the
* 'processed' and 'read' driver indexes as well)
* + A received packet is processed and handed to the kernel network stack,
* detached from the iwl->rxq. The driver 'processed' index is updated.
* + The Host/Firmware iwl->rxq is replenished at tasklet time from the rx_free
* list. If there are no allocated buffers in iwl->rxq->rx_free, the READ
* INDEX is not incremented and iwl->status(RX_STALLED) is set. If there
* were enough free buffers and RX_STALLED is set it is cleared.
*
*
* Driver sequence:
*
* il_rx_queue_alloc() Allocates rx_free
* il_rx_replenish() Replenishes rx_free list from rx_used, and calls
* il_rx_queue_restock
* il_rx_queue_restock() Moves available buffers from rx_free into Rx
* queue, updates firmware pointers, and updates
* the WRITE index. If insufficient rx_free buffers
* are available, schedules il_rx_replenish
*
* -- enable interrupts --
* ISR - il_rx() Detach il_rx_bufs from pool up to the
* READ INDEX, detaching the SKB from the pool.
* Moves the packet buffer from queue to rx_used.
* Calls il_rx_queue_restock to refill any empty
* slots.
* ...
*
*/
/**
* il_rx_queue_space - Return number of free slots available in queue.
*/
int il_rx_queue_space(const struct il_rx_queue *q)
{
int s = q->read - q->write;
if (s <= 0)
s += RX_QUEUE_SIZE;
/* keep some buffer to not confuse full and empty queue */
s -= 2;
if (s < 0)
s = 0;
return s;
}
EXPORT_SYMBOL(il_rx_queue_space);
/**
* il_rx_queue_update_write_ptr - Update the write pointer for the RX queue
*/
void
il_rx_queue_update_write_ptr(struct il_priv *il,
struct il_rx_queue *q)
{
unsigned long flags;
u32 rx_wrt_ptr_reg = il->hw_params.rx_wrt_ptr_reg;
u32 reg;
spin_lock_irqsave(&q->lock, flags);
if (q->need_update == 0)
goto exit_unlock;
/* If power-saving is in use, make sure device is awake */
if (test_bit(STATUS_POWER_PMI, &il->status)) {
reg = _il_rd(il, CSR_UCODE_DRV_GP1);
if (reg & CSR_UCODE_DRV_GP1_BIT_MAC_SLEEP) {
D_INFO(
"Rx queue requesting wakeup,"
" GP1 = 0x%x\n", reg);
il_set_bit(il, CSR_GP_CNTRL,
CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
goto exit_unlock;
}
q->write_actual = (q->write & ~0x7);
il_wr(il, rx_wrt_ptr_reg,
q->write_actual);
/* Else device is assumed to be awake */
} else {
/* Device expects a multiple of 8 */
q->write_actual = (q->write & ~0x7);
il_wr(il, rx_wrt_ptr_reg,
q->write_actual);
}
q->need_update = 0;
exit_unlock:
spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL(il_rx_queue_update_write_ptr);
int il_rx_queue_alloc(struct il_priv *il)
{
struct il_rx_queue *rxq = &il->rxq;
struct device *dev = &il->pci_dev->dev;
int i;
spin_lock_init(&rxq->lock);
INIT_LIST_HEAD(&rxq->rx_free);
INIT_LIST_HEAD(&rxq->rx_used);
/* Alloc the circular buffer of Read Buffer Descriptors (RBDs) */
rxq->bd = dma_alloc_coherent(dev, 4 * RX_QUEUE_SIZE, &rxq->bd_dma,
GFP_KERNEL);
if (!rxq->bd)
goto err_bd;
rxq->rb_stts = dma_alloc_coherent(dev, sizeof(struct il_rb_status),
&rxq->rb_stts_dma, GFP_KERNEL);
if (!rxq->rb_stts)
goto err_rb;
/* Fill the rx_used queue with _all_ of the Rx buffers */
for (i = 0; i < RX_FREE_BUFFERS + RX_QUEUE_SIZE; i++)
list_add_tail(&rxq->pool[i].list, &rxq->rx_used);
/* Set us so that we have processed and used all buffers, but have
* not restocked the Rx queue with fresh buffers */
rxq->read = rxq->write = 0;
rxq->write_actual = 0;
rxq->free_count = 0;
rxq->need_update = 0;
return 0;
err_rb:
dma_free_coherent(&il->pci_dev->dev, 4 * RX_QUEUE_SIZE, rxq->bd,
rxq->bd_dma);
err_bd:
return -ENOMEM;
}
EXPORT_SYMBOL(il_rx_queue_alloc);
void il_rx_spectrum_measure_notif(struct il_priv *il,
struct il_rx_buf *rxb)
{
struct il_rx_pkt *pkt = rxb_addr(rxb);
struct il_spectrum_notification *report = &(pkt->u.spectrum_notif);
if (!report->state) {
D_11H(
"Spectrum Measure Notification: Start\n");
return;
}
memcpy(&il->measure_report, report, sizeof(*report));
il->measurement_status |= MEASUREMENT_READY;
}
EXPORT_SYMBOL(il_rx_spectrum_measure_notif);
/*
* returns non-zero if packet should be dropped
*/
int il_set_decrypted_flag(struct il_priv *il,
struct ieee80211_hdr *hdr,
u32 decrypt_res,
struct ieee80211_rx_status *stats)
{
u16 fc = le16_to_cpu(hdr->frame_control);
/*
* All contexts have the same setting here due to it being
* a module parameter, so OK to check any context.
*/
if (il->ctx.active.filter_flags &
RXON_FILTER_DIS_DECRYPT_MSK)
return 0;
if (!(fc & IEEE80211_FCTL_PROTECTED))
return 0;
D_RX("decrypt_res:0x%x\n", decrypt_res);
switch (decrypt_res & RX_RES_STATUS_SEC_TYPE_MSK) {
case RX_RES_STATUS_SEC_TYPE_TKIP:
/* The uCode has got a bad phase 1 Key, pushes the packet.
* Decryption will be done in SW. */
if ((decrypt_res & RX_RES_STATUS_DECRYPT_TYPE_MSK) ==
RX_RES_STATUS_BAD_KEY_TTAK)
break;
case RX_RES_STATUS_SEC_TYPE_WEP:
if ((decrypt_res & RX_RES_STATUS_DECRYPT_TYPE_MSK) ==
RX_RES_STATUS_BAD_ICV_MIC) {
/* bad ICV, the packet is destroyed since the
* decryption is inplace, drop it */
D_RX("Packet destroyed\n");
return -1;
}
case RX_RES_STATUS_SEC_TYPE_CCMP:
if ((decrypt_res & RX_RES_STATUS_DECRYPT_TYPE_MSK) ==
RX_RES_STATUS_DECRYPT_OK) {
D_RX("hw decrypt successfully!!!\n");
stats->flag |= RX_FLAG_DECRYPTED;
}
break;
default:
break;
}
return 0;
}
EXPORT_SYMBOL(il_set_decrypted_flag);
