Commit:     5c91fb902d4e6f6006faf45edd3f25932cb7d58c
Parent:     1754a5d9f97f16f729066b8f125351af4951d6fe
Author:     Michael Hennerich <[EMAIL PROTECTED]>
AuthorDate: Sat Nov 17 23:46:58 2007 +0800
Committer:  Bryan Wu <[EMAIL PROTECTED]>
CommitDate: Sat Nov 17 23:46:58 2007 +0800

    Blackfin arch: Add assembly function insl_16
     * CPUs often take a performance hit when accessing unaligned memory
     * locations. The actual performance hit varies, it can be small if the
     * hardware handles it or large if we have to take an exception and fix
     * it
     * in software.
     * Since an ethernet header is 14 bytes network drivers often end up
     * with
     * the IP header at an unaligned offset. The IP header can be aligned by
     * shifting the start of the packet by 2 bytes. Drivers should do this
     * with:
     * skb_reserve(NET_IP_ALIGN);
     * The downside to this alignment of the IP header is that the DMA is
     * now
     * unaligned. On some architectures the cost of an unaligned DMA is high
     * and this cost outweighs the gains made by aligning the IP header.
     * Since this trade off varies between architectures, we allow
     * to be overridden.
    This new function insl_16 allows to read form 32-bit IO and writes to
    16-bit aligned memory. This is useful in above described scenario -
    In particular with the AXIS AX88180 Gigabit Ethernet MAC.
    Once the device is in 32-bit mode, reads from the RX FIFO always
    decrements 4bytes.
    While on the other side the destination address in SDRAM is always
    16-bit aligned.
    If we use skb_reserve(0) the receive buffer is 32-bit aligned but later
    we hit a unaligned exception in the IP code.
    Signed-off-by: Michael Hennerich <[EMAIL PROTECTED]>
    Signed-off-by: Bryan Wu <[EMAIL PROTECTED]>
 arch/blackfin/kernel/bfin_ksyms.c |    1 +
 arch/blackfin/lib/ins.S           |   19 +++++++++++++++++++
 include/asm-blackfin/io.h         |    1 +
 3 files changed, 21 insertions(+), 0 deletions(-)

diff --git a/arch/blackfin/kernel/bfin_ksyms.c 
index 5dad9d3..b3fa7d8 100644
--- a/arch/blackfin/kernel/bfin_ksyms.c
+++ b/arch/blackfin/kernel/bfin_ksyms.c
@@ -100,6 +100,7 @@ EXPORT_SYMBOL(outsw);
diff --git a/arch/blackfin/lib/ins.S b/arch/blackfin/lib/ins.S
index a17cc77..df7b883 100644
--- a/arch/blackfin/lib/ins.S
+++ b/arch/blackfin/lib/ins.S
@@ -77,3 +77,22 @@ ENTRY(_insb)
        sti R3;
+       P0 = R0;        /* P0 = port */
+       cli R3;
+       P1 = R1;        /* P1 = address */
+       P2 = R2;        /* P2 = count */
+       SSYNC;
+       LSETUP( .Llong16_loop_s, .Llong16_loop_e) LC0 = P2;
+.Llong16_loop_s:  R0 = [P0];
+                 W[P1++] = R0;
+                 R0 = R0 >> 16;
+                 W[P1++] = R0;
+                 NOP;
+.Llong16_loop_e:  NOP;
+       sti R3;
+       RTS;
diff --git a/include/asm-blackfin/io.h b/include/asm-blackfin/io.h
index d1d2e6b..1601d62 100644
--- a/include/asm-blackfin/io.h
+++ b/include/asm-blackfin/io.h
@@ -122,6 +122,7 @@ extern void outsl(unsigned long port, const void *addr, 
unsigned long count);
 extern void insb(unsigned long port, void *addr, unsigned long count);
 extern void insw(unsigned long port, void *addr, unsigned long count);
 extern void insl(unsigned long port, void *addr, unsigned long count);
+extern void insl_16(unsigned long port, void *addr, unsigned long count);
 extern void dma_outsb(unsigned long port, const void *addr, unsigned short 
 extern void dma_outsw(unsigned long port, const void *addr, unsigned short 
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