qlge: Get rid of volatile usage for shadow register.

Putting back ql_read_sh_reg() function and using rmb() instead of
volatile.

Signed-off-by: Ron Mercer <ron.mercer@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 2 deletions

diff --git a/drivers/net/qlge/qlge.h b/drivers/net/qlge/qlge.h
index 459663a4023d..4cb3647bb1b0 100644
--- a/drivers/net/qlge/qlge.h
+++ b/drivers/net/qlge/qlge.h
@@ -1145,7 +1145,7 @@ struct tx_ring {
         struct wqicb wqicb;     /* structure used to inform chip of new queue */
         void *wq_base;          /* pci_alloc:virtual addr for tx */
         dma_addr_t wq_base_dma; /* pci_alloc:dma addr for tx */
-        u32 *cnsmr_idx_sh_reg;  /* shadow copy of consumer idx */
+        __le32 *cnsmr_idx_sh_reg;       /* shadow copy of consumer idx */
         dma_addr_t cnsmr_idx_sh_reg_dma;        /* dma-shadow copy of consumer */
         u32 wq_size;            /* size in bytes of queue area */
         u32 wq_len;             /* number of entries in queue */
@@ -1181,7 +1181,7 @@ struct rx_ring {
         u32 cq_size;
         u32 cq_len;
         u16 cq_id;
-        volatile __le32 *prod_idx_sh_reg;       /* Shadowed producer register. */
+        __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 */
@@ -1459,6 +1459,24 @@ 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 u32 ql_read_sh_reg(__le32  *addr)
+{
+        u32 reg;
+        reg =  le32_to_cpu(*addr);
+        rmb();
+        return reg;
+}
+
 extern char qlge_driver_name[];
 extern const char qlge_driver_version[];
 extern const struct ethtool_ops qlge_ethtool_ops;