atl1: simplify tx packet descriptor

The transmit packet descriptor consists of four 32-bit words, with word 3
upper bits overloaded depending upon the condition of its bits 3 and 4.
The driver currently duplicates all word 2 and some word 3 register bit
definitions unnecessarily and also uses a set of nested structures in its
definition of the TPD without good cause. This patch adds a lengthy
comment describing the TPD, eliminates duplicate TPD bit definitions,
and simplifies the TPD structure itself. It also expands the TSO check
to correctly handle custom checksum versus TSO processing using the revised
TPD definitions. Finally, shorten some variable names in the transmit
processing path to reduce line lengths, rename some variables to better
describe their purpose (e.g., nseg versus m), and add a comment or two
to better describe what the code is doing.

Signed-off-by: Jay Cliburn <jacliburn@bellsouth.net>
Acked-by: Chris Snook <csnook@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 105 insertions, 96 deletions

diff --git a/drivers/net/atlx/atl1.h b/drivers/net/atlx/atl1.h
index 30c5a8d72f3a..4d3d65b0cf57 100644
--- a/drivers/net/atlx/atl1.h
+++ b/drivers/net/atlx/atl1.h
@@ -452,106 +452,115 @@ struct rx_free_desc {
         /* __attribute__ ((packed)) is required */
 } __attribute__ ((packed));
 
-/* tsopu defines */
-#define TSO_PARAM_BUFLEN_MASK           0x3FFF
-#define TSO_PARAM_BUFLEN_SHIFT          0
-#define TSO_PARAM_DMAINT_MASK           0x0001
-#define TSO_PARAM_DMAINT_SHIFT          14
-#define TSO_PARAM_PKTNT_MASK            0x0001
-#define TSO_PARAM_PKTINT_SHIFT          15
-#define TSO_PARAM_VLANTAG_MASK          0xFFFF
-#define TSO_PARAM_VLAN_SHIFT            16
-
-/* tsopl defines */
-#define TSO_PARAM_EOP_MASK              0x0001
-#define TSO_PARAM_EOP_SHIFT             0
-#define TSO_PARAM_COALESCE_MASK         0x0001
-#define TSO_PARAM_COALESCE_SHIFT        1
-#define TSO_PARAM_INSVLAG_MASK          0x0001
-#define TSO_PARAM_INSVLAG_SHIFT         2
-#define TSO_PARAM_CUSTOMCKSUM_MASK      0x0001
-#define TSO_PARAM_CUSTOMCKSUM_SHIFT     3
-#define TSO_PARAM_SEGMENT_MASK          0x0001
-#define TSO_PARAM_SEGMENT_SHIFT         4
-#define TSO_PARAM_IPCKSUM_MASK          0x0001
-#define TSO_PARAM_IPCKSUM_SHIFT         5
-#define TSO_PARAM_TCPCKSUM_MASK         0x0001
-#define TSO_PARAM_TCPCKSUM_SHIFT        6
-#define TSO_PARAM_UDPCKSUM_MASK         0x0001
-#define TSO_PARAM_UDPCKSUM_SHIFT        7
-#define TSO_PARAM_VLANTAGGED_MASK       0x0001
-#define TSO_PARAM_VLANTAGGED_SHIFT      8
-#define TSO_PARAM_ETHTYPE_MASK          0x0001
-#define TSO_PARAM_ETHTYPE_SHIFT         9
-#define TSO_PARAM_IPHL_MASK             0x000F
-#define TSO_PARAM_IPHL_SHIFT            10
-#define TSO_PARAM_TCPHDRLEN_MASK        0x000F
-#define TSO_PARAM_TCPHDRLEN_SHIFT       14
-#define TSO_PARAM_HDRFLAG_MASK          0x0001
-#define TSO_PARAM_HDRFLAG_SHIFT         18
-#define TSO_PARAM_MSS_MASK              0x1FFF
-#define TSO_PARAM_MSS_SHIFT             19
-
-/* csumpu defines */
-#define CSUM_PARAM_BUFLEN_MASK          0x3FFF
-#define CSUM_PARAM_BUFLEN_SHIFT         0
-#define CSUM_PARAM_DMAINT_MASK          0x0001
-#define CSUM_PARAM_DMAINT_SHIFT         14
-#define CSUM_PARAM_PKTINT_MASK          0x0001
-#define CSUM_PARAM_PKTINT_SHIFT         15
-#define CSUM_PARAM_VALANTAG_MASK        0xFFFF
-#define CSUM_PARAM_VALAN_SHIFT          16
-
-/* csumpl defines*/
-#define CSUM_PARAM_EOP_MASK             0x0001
-#define CSUM_PARAM_EOP_SHIFT            0
-#define CSUM_PARAM_COALESCE_MASK        0x0001
-#define CSUM_PARAM_COALESCE_SHIFT       1
-#define CSUM_PARAM_INSVLAG_MASK         0x0001
-#define CSUM_PARAM_INSVLAG_SHIFT        2
-#define CSUM_PARAM_CUSTOMCKSUM_MASK     0x0001
-#define CSUM_PARAM_CUSTOMCKSUM_SHIFT    3
-#define CSUM_PARAM_SEGMENT_MASK         0x0001
-#define CSUM_PARAM_SEGMENT_SHIFT        4
-#define CSUM_PARAM_IPCKSUM_MASK         0x0001
-#define CSUM_PARAM_IPCKSUM_SHIFT        5
-#define CSUM_PARAM_TCPCKSUM_MASK        0x0001
-#define CSUM_PARAM_TCPCKSUM_SHIFT       6
-#define CSUM_PARAM_UDPCKSUM_MASK        0x0001
-#define CSUM_PARAM_UDPCKSUM_SHIFT       7
-#define CSUM_PARAM_VLANTAGGED_MASK      0x0001
-#define CSUM_PARAM_VLANTAGGED_SHIFT     8
-#define CSUM_PARAM_ETHTYPE_MASK         0x0001
-#define CSUM_PARAM_ETHTYPE_SHIFT        9
-#define CSUM_PARAM_IPHL_MASK            0x000F
-#define CSUM_PARAM_IPHL_SHIFT           10
-#define CSUM_PARAM_PLOADOFFSET_MASK     0x00FF
-#define CSUM_PARAM_PLOADOFFSET_SHIFT    16
-#define CSUM_PARAM_XSUMOFFSET_MASK      0x00FF
-#define CSUM_PARAM_XSUMOFFSET_SHIFT     24
-
-/* TPD descriptor */
-struct tso_param {
-        /* The order of these declarations is important -- don't change it */
-        u32 tsopu;      /* tso_param upper word */
-        u32 tsopl;      /* tso_param lower word */
-};
-
-struct csum_param {
-        /* The order of these declarations is important -- don't change it */
-        u32 csumpu;     /* csum_param upper word */
-        u32 csumpl;     /* csum_param lower word */
-};
+/*
+ * The L1 transmit packet descriptor is comprised of four 32-bit words.
+ *
+ *      31                                      0
+ *      +---------------------------------------+
+ *      |       Word 0: Buffer addr lo          |
+ *      +---------------------------------------+
+ *      |       Word 1: Buffer addr hi          |
+ *      +---------------------------------------+
+ *      |               Word 2                  |
+ *      +---------------------------------------+
+ *      |               Word 3                  |
+ *      +---------------------------------------+
+ *
+ * Words 0 and 1 combine to form a 64-bit buffer address.
+ *
+ * Word 2 is self explanatory in the #define block below.
+ *
+ * Word 3 has two forms, depending upon the state of bits 3 and 4.
+ * If bits 3 and 4 are both zero, then bits 14:31 are unused by the
+ * hardware.  Otherwise, if either bit 3 or 4 is set, the definition
+ * of bits 14:31 vary according to the following depiction.
+ *
+ *      0       End of packet                   0       End of packet
+ *      1       Coalesce                        1       Coalesce
+ *      2       Insert VLAN tag                 2       Insert VLAN tag
+ *      3       Custom csum enable = 0          3       Custom csum enable = 1
+ *      4       Segment enable = 1              4       Segment enable = 0
+ *      5       Generate IP checksum            5       Generate IP checksum
+ *      6       Generate TCP checksum           6       Generate TCP checksum
+ *      7       Generate UDP checksum           7       Generate UDP checksum
+ *      8       VLAN tagged                     8       VLAN tagged
+ *      9       Ethernet frame type             9       Ethernet frame type
+ *      10-+                                    10-+
+ *      11 |    IP hdr length (10:13)           11 |    IP hdr length (10:13)
+ *      12 |    (num 32-bit words)              12 |    (num 32-bit words)
+ *      13-+                                    13-+
+ *      14-+                                    14      Unused
+ *      15 |    TCP hdr length (14:17)          15      Unused
+ *      16 |    (num 32-bit words)              16-+
+ *      17-+                                    17 |
+ *      18      Header TPD flag                 18 |
+ *      19-+                                    19 |    Payload offset
+ *      20 |                                    20 |        (16:23)
+ *      21 |                                    21 |
+ *      22 |                                    22 |
+ *      23 |                                    23-+
+ *      24 |                                    24-+
+ *      25 |    MSS (19:31)                     25 |
+ *      26 |                                    26 |
+ *      27 |                                    27 |    Custom csum offset
+ *      28 |                                    28 |         (24:31)
+ *      29 |                                    29 |
+ *      30 |                                    30 |
+ *      31-+                                    31-+
+ */
 
-union tpd_descr {
-        u64 data;
-        struct csum_param csum;
-        struct tso_param tso;
-};
+/* tpd word 2 */
+#define TPD_BUFLEN_MASK         0x3FFF
+#define TPD_BUFLEN_SHIFT        0
+#define TPD_DMAINT_MASK         0x0001
+#define TPD_DMAINT_SHIFT        14
+#define TPD_PKTNT_MASK          0x0001
+#define TPD_PKTINT_SHIFT        15
+#define TPD_VLANTAG_MASK        0xFFFF
+#define TPD_VLAN_SHIFT          16
+
+/* tpd word 3 bits 0:13 */
+#define TPD_EOP_MASK            0x0001
+#define TPD_EOP_SHIFT           0
+#define TPD_COALESCE_MASK       0x0001
+#define TPD_COALESCE_SHIFT      1
+#define TPD_INS_VL_TAG_MASK     0x0001
+#define TPD_INS_VL_TAG_SHIFT    2
+#define TPD_CUST_CSUM_EN_MASK   0x0001
+#define TPD_CUST_CSUM_EN_SHIFT  3
+#define TPD_SEGMENT_EN_MASK     0x0001
+#define TPD_SEGMENT_EN_SHIFT    4
+#define TPD_IP_CSUM_MASK        0x0001
+#define TPD_IP_CSUM_SHIFT       5
+#define TPD_TCP_CSUM_MASK       0x0001
+#define TPD_TCP_CSUM_SHIFT      6
+#define TPD_UDP_CSUM_MASK       0x0001
+#define TPD_UDP_CSUM_SHIFT      7
+#define TPD_VL_TAGGED_MASK      0x0001
+#define TPD_VL_TAGGED_SHIFT     8
+#define TPD_ETHTYPE_MASK        0x0001
+#define TPD_ETHTYPE_SHIFT       9
+#define TPD_IPHL_MASK           0x000F
+#define TPD_IPHL_SHIFT          10
+
+/* tpd word 3 bits 14:31 if segment enabled */
+#define TPD_TCPHDRLEN_MASK      0x000F
+#define TPD_TCPHDRLEN_SHIFT     14
+#define TPD_HDRFLAG_MASK        0x0001
+#define TPD_HDRFLAG_SHIFT       18
+#define TPD_MSS_MASK            0x1FFF
+#define TPD_MSS_SHIFT           19
+
+/* tpd word 3 bits 16:31 if custom csum enabled */
+#define TPD_PLOADOFFSET_MASK    0x00FF
+#define TPD_PLOADOFFSET_SHIFT   16
+#define TPD_CCSUMOFFSET_MASK    0x00FF
+#define TPD_CCSUMOFFSET_SHIFT   24
 
 struct tx_packet_desc {
         __le64 buffer_addr;
-        union tpd_descr desc;
+        __le32 word2;
+        __le32 word3;
 };
 
 /* DMA Order Settings */