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qlge: bugfix: Fix shadow register endian issue.
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Shadow registers are consistent memory locations to which the chip
echos ring indexes in little endian format.  These values need to
be endian swapped before referencing.

Note:
The register pointer declaration uses the volatile modifier which
causes warnings in checkpatch.
Per Documentation/volatile-considered-harmful.txt:
  - Pointers to data structures in coherent memory which might be modified
    by I/O devices can, sometimes, legitimately be volatile.  A ring buffer
    used by a network adapter, where that adapter changes pointers to
    indicate which descriptors have been processed, is an example of this
    type of situation.

Signed-off-by: Ron Mercer <ron.mercer@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Ron Mercer authored and David S. Miller committed Jan 5, 2009
1 parent 4055c7d commit 2b72c78
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Showing 2 changed files with 7 additions and 22 deletions.
17 changes: 1 addition & 16 deletions drivers/net/qlge/qlge.h
Original file line number Diff line number Diff line change
Expand Up @@ -1189,7 +1189,7 @@ struct rx_ring {
u32 cq_size;
u32 cq_len;
u16 cq_id;
u32 *prod_idx_sh_reg; /* Shadowed producer register. */
volatile __le32 *prod_idx_sh_reg; /* Shadowed producer register. */
dma_addr_t prod_idx_sh_reg_dma;
void __iomem *cnsmr_idx_db_reg; /* PCI doorbell mem area + 0 */
u32 cnsmr_idx; /* current sw idx */
Expand Down Expand Up @@ -1467,21 +1467,6 @@ static inline void ql_write_db_reg(u32 val, void __iomem *addr)
mmiowb();
}

/*
* Shadow Registers:
* Outbound queues have a consumer index that is maintained by the chip.
* Inbound queues have a producer index that is maintained by the chip.
* For lower overhead, these registers are "shadowed" to host memory
* which allows the device driver to track the queue progress without
* PCI reads. When an entry is placed on an inbound queue, the chip will
* update the relevant index register and then copy the value to the
* shadow register in host memory.
*/
static inline unsigned int ql_read_sh_reg(const volatile void *addr)
{
return *(volatile unsigned int __force *)addr;
}

extern char qlge_driver_name[];
extern const char qlge_driver_version[];
extern const struct ethtool_ops qlge_ethtool_ops;
Expand Down
12 changes: 6 additions & 6 deletions drivers/net/qlge/qlge_main.c
Original file line number Diff line number Diff line change
Expand Up @@ -1559,7 +1559,7 @@ static void ql_process_chip_ae_intr(struct ql_adapter *qdev,
static int ql_clean_outbound_rx_ring(struct rx_ring *rx_ring)
{
struct ql_adapter *qdev = rx_ring->qdev;
u32 prod = ql_read_sh_reg(rx_ring->prod_idx_sh_reg);
u32 prod = le32_to_cpu(*rx_ring->prod_idx_sh_reg);
struct ob_mac_iocb_rsp *net_rsp = NULL;
int count = 0;

Expand All @@ -1585,7 +1585,7 @@ static int ql_clean_outbound_rx_ring(struct rx_ring *rx_ring)
}
count++;
ql_update_cq(rx_ring);
prod = ql_read_sh_reg(rx_ring->prod_idx_sh_reg);
prod = le32_to_cpu(*rx_ring->prod_idx_sh_reg);
}
ql_write_cq_idx(rx_ring);
if (netif_queue_stopped(qdev->ndev) && net_rsp != NULL) {
Expand All @@ -1605,7 +1605,7 @@ static int ql_clean_outbound_rx_ring(struct rx_ring *rx_ring)
static int ql_clean_inbound_rx_ring(struct rx_ring *rx_ring, int budget)
{
struct ql_adapter *qdev = rx_ring->qdev;
u32 prod = ql_read_sh_reg(rx_ring->prod_idx_sh_reg);
u32 prod = le32_to_cpu(*rx_ring->prod_idx_sh_reg);
struct ql_net_rsp_iocb *net_rsp;
int count = 0;

Expand Down Expand Up @@ -1638,7 +1638,7 @@ static int ql_clean_inbound_rx_ring(struct rx_ring *rx_ring, int budget)
}
count++;
ql_update_cq(rx_ring);
prod = ql_read_sh_reg(rx_ring->prod_idx_sh_reg);
prod = le32_to_cpu(*rx_ring->prod_idx_sh_reg);
if (count == budget)
break;
}
Expand Down Expand Up @@ -1801,7 +1801,7 @@ static irqreturn_t qlge_isr(int irq, void *dev_id)
* Check the default queue and wake handler if active.
*/
rx_ring = &qdev->rx_ring[0];
if (ql_read_sh_reg(rx_ring->prod_idx_sh_reg) != rx_ring->cnsmr_idx) {
if (le32_to_cpu(*rx_ring->prod_idx_sh_reg) != rx_ring->cnsmr_idx) {
QPRINTK(qdev, INTR, INFO, "Waking handler for rx_ring[0].\n");
ql_disable_completion_interrupt(qdev, intr_context->intr);
queue_delayed_work_on(smp_processor_id(), qdev->q_workqueue,
Expand All @@ -1815,7 +1815,7 @@ static irqreturn_t qlge_isr(int irq, void *dev_id)
*/
for (i = 1; i < qdev->rx_ring_count; i++) {
rx_ring = &qdev->rx_ring[i];
if (ql_read_sh_reg(rx_ring->prod_idx_sh_reg) !=
if (le32_to_cpu(*rx_ring->prod_idx_sh_reg) !=
rx_ring->cnsmr_idx) {
QPRINTK(qdev, INTR, INFO,
"Waking handler for rx_ring[%d].\n", i);
Expand Down

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