sfc: Cleanups in io.h

Most of the Falcon locking description does not apply to EF10.

Signed-off-by: Martin Habets <habetsm.xilinx@gmail.com>
Acked-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 9 insertions, 80 deletions

diff --git a/drivers/net/ethernet/sfc/io.h b/drivers/net/ethernet/sfc/io.h
index 30439cc83a89..7432c09010d6 100644
--- a/drivers/net/ethernet/sfc/io.h
+++ b/drivers/net/ethernet/sfc/io.h
@@ -17,46 +17,22 @@
  *
  **************************************************************************
  *
- * Notes on locking strategy for the Falcon architecture:
- *
- * Many CSRs are very wide and cannot be read or written atomically.
- * Writes from the host are buffered by the Bus Interface Unit (BIU)
- * up to 128 bits.  Whenever the host writes part of such a register,
- * the BIU collects the written value and does not write to the
- * underlying register until all 4 dwords have been written.  A
- * similar buffering scheme applies to host access to the NIC's 64-bit
- * SRAM.
- *
- * Writes to different CSRs and 64-bit SRAM words must be serialised,
- * since interleaved access can result in lost writes.  We use
- * efx_nic::biu_lock for this.
- *
- * We also serialise reads from 128-bit CSRs and SRAM with the same
- * spinlock.  This may not be necessary, but it doesn't really matter
- * as there are no such reads on the fast path.
+ * The EF10 architecture exposes very few registers to the host and
+ * most of them are only 32 bits wide.  The only exceptions are the MC
+ * doorbell register pair, which has its own latching, and
+ * TX_DESC_UPD.
  *
- * The DMA descriptor pointers (RX_DESC_UPD and TX_DESC_UPD) are
- * 128-bit but are special-cased in the BIU to avoid the need for
- * locking in the host:
+ * The TX_DESC_UPD DMA descriptor pointer is 128-bits but is a special
+ * case in the BIU to avoid the need for locking in the host:
  *
- * - They are write-only.
- * - The semantics of writing to these registers are such that
+ * - It is write-only.
+ * - The semantics of writing to this register is such that
  *   replacing the low 96 bits with zero does not affect functionality.
- * - If the host writes to the last dword address of such a register
+ * - If the host writes to the last dword address of the register
  *   (i.e. the high 32 bits) the underlying register will always be
  *   written.  If the collector and the current write together do not
  *   provide values for all 128 bits of the register, the low 96 bits
  *   will be written as zero.
- * - If the host writes to the address of any other part of such a
- *   register while the collector already holds values for some other
- *   register, the write is discarded and the collector maintains its
- *   current state.
- *
- * The EF10 architecture exposes very few registers to the host and
- * most of them are only 32 bits wide.  The only exceptions are the MC
- * doorbell register pair, which has its own latching, and
- * TX_DESC_UPD, which works in a similar way to the Falcon
- * architecture.
  */
 
 #if BITS_PER_LONG == 64
@@ -125,27 +101,6 @@ static inline void efx_writeo(struct efx_nic *efx, const efx_oword_t *value,
 	spin_unlock_irqrestore(&efx->biu_lock, flags);
 }
 
-/* Write 64-bit SRAM through the supplied mapping, locking as appropriate. */
-static inline void efx_sram_writeq(struct efx_nic *efx, void __iomem *membase,
-				   const efx_qword_t *value, unsigned int index)
-{
-	unsigned int addr = index * sizeof(*value);
-	unsigned long flags __attribute__ ((unused));
-
-	netif_vdbg(efx, hw, efx->net_dev,
-		   "writing SRAM address %x with " EFX_QWORD_FMT "\n",
-		   addr, EFX_QWORD_VAL(*value));
-
-	spin_lock_irqsave(&efx->biu_lock, flags);
-#ifdef EFX_USE_QWORD_IO
-	__raw_writeq((__force u64)value->u64[0], membase + addr);
-#else
-	__raw_writel((__force u32)value->u32[0], membase + addr);
-	__raw_writel((__force u32)value->u32[1], membase + addr + 4);
-#endif
-	spin_unlock_irqrestore(&efx->biu_lock, flags);
-}
-
 /* Write a 32-bit CSR or the last dword of a special 128-bit CSR */
 static inline void efx_writed(struct efx_nic *efx, const efx_dword_t *value,
 			      unsigned int reg)
@@ -176,27 +131,6 @@ static inline void efx_reado(struct efx_nic *efx, efx_oword_t *value,
 		   EFX_OWORD_VAL(*value));
 }
 
-/* Read 64-bit SRAM through the supplied mapping, locking as appropriate. */
-static inline void efx_sram_readq(struct efx_nic *efx, void __iomem *membase,
-				  efx_qword_t *value, unsigned int index)
-{
-	unsigned int addr = index * sizeof(*value);
-	unsigned long flags __attribute__ ((unused));
-
-	spin_lock_irqsave(&efx->biu_lock, flags);
-#ifdef EFX_USE_QWORD_IO
-	value->u64[0] = (__force __le64)__raw_readq(membase + addr);
-#else
-	value->u32[0] = (__force __le32)__raw_readl(membase + addr);
-	value->u32[1] = (__force __le32)__raw_readl(membase + addr + 4);
-#endif
-	spin_unlock_irqrestore(&efx->biu_lock, flags);
-
-	netif_vdbg(efx, hw, efx->net_dev,
-		   "read from SRAM address %x, got "EFX_QWORD_FMT"\n",
-		   addr, EFX_QWORD_VAL(*value));
-}
-
 /* Read a 32-bit CSR or SRAM */
 static inline void efx_readd(struct efx_nic *efx, efx_dword_t *value,
 				unsigned int reg)
diff --git a/drivers/net/ethernet/sfc/nic.c b/drivers/net/ethernet/sfc/nic.c
index 7e057741425f..a33ed473cc8a 100644
--- a/drivers/net/ethernet/sfc/nic.c
+++ b/drivers/net/ethernet/sfc/nic.c
@@ -272,11 +272,6 @@ void efx_nic_get_regs(struct efx_nic *efx, void *buf)
 			case 4: /* 32-bit SRAM */
 				efx_readd(efx, buf, table->offset + 4 * i);
 				break;
-			case 8: /* 64-bit SRAM */
-				efx_sram_readq(efx,
-					       efx->membase + table->offset,
-					       buf, i);
-				break;
 			case 16: /* 128-bit-readable register */
 				efx_reado_table(efx, buf, table->offset, i);
 				break;