[src/trunk]: src/sys/arch/arm/broadcom Only use 128-bit mode when the transfe...

[skrll <skrll%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/bb7e69979625
branches:  trunk
changeset: 804140:bb7e69979625
user:      skrll <skrll%NetBSD.org@localhost>
date:      Tue Nov 25 14:30:05 2014 +0000

description:
Only use 128-bit mode when the transfer is a multiple of this.

>From Jared (the arm periph guy)

diffstat:

 sys/arch/arm/broadcom/bcm2835_emmc.c |  27 +++++++++++++++++++++------
 1 files changed, 21 insertions(+), 6 deletions(-)

diffs (64 lines):

diff -r 6ded8fedcab2 -r bb7e69979625 sys/arch/arm/broadcom/bcm2835_emmc.c
--- a/sys/arch/arm/broadcom/bcm2835_emmc.c      Tue Nov 25 13:42:31 2014 +0000
+++ b/sys/arch/arm/broadcom/bcm2835_emmc.c      Tue Nov 25 14:30:05 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: bcm2835_emmc.c,v 1.19 2014/10/04 18:10:04 jmcneill Exp $       */
+/*     $NetBSD: bcm2835_emmc.c,v 1.20 2014/11/25 14:30:05 skrll Exp $  */
 
 /*-
  * Copyright (c) 2012 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: bcm2835_emmc.c,v 1.19 2014/10/04 18:10:04 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: bcm2835_emmc.c,v 1.20 2014/11/25 14:30:05 skrll Exp $");
 
 #include "bcmdmac.h"
 
@@ -248,9 +248,21 @@
        for (seg = 0; seg < cmd->c_dmamap->dm_nsegs; seg++) {
                sc->sc_cblk[seg].cb_ti =
                    __SHIFTIN(11, DMAC_TI_PERMAP); /* e.MMC */
+               sc->sc_cblk[seg].cb_txfr_len =
+                   cmd->c_dmamap->dm_segs[seg].ds_len;
+               /*
+                * All transfers are assumed to be multiples of 32-bits.
+                */
+               KASSERTMSG((sc->sc_cblk[seg].cb_txfr_len & 0x3) == 0,
+                   "seg %zu len %d", seg, sc->sc_cblk[seg].cb_txfr_len);
                if (ISSET(cmd->c_flags, SCF_CMD_READ)) {
                        sc->sc_cblk[seg].cb_ti |= DMAC_TI_DEST_INC;
-                       sc->sc_cblk[seg].cb_ti |= DMAC_TI_DEST_WIDTH;
+                       /*
+                        * Use 128-bit mode if transfer is a multiple of
+                        * 16-bytes.
+                        */
+                       if ((sc->sc_cblk[seg].cb_txfr_len & 0xf) == 0)
+                               sc->sc_cblk[seg].cb_ti |= DMAC_TI_DEST_WIDTH;
                        sc->sc_cblk[seg].cb_ti |= DMAC_TI_SRC_DREQ;
                        sc->sc_cblk[seg].cb_source_ad =
                            BCM2835_PERIPHERALS_TO_BUS(sc->sc_physaddr +
@@ -259,7 +271,12 @@
                            cmd->c_dmamap->dm_segs[seg].ds_addr;
                } else {
                        sc->sc_cblk[seg].cb_ti |= DMAC_TI_SRC_INC;
-                       sc->sc_cblk[seg].cb_ti |= DMAC_TI_SRC_WIDTH;
+                       /*
+                        * Use 128-bit mode if transfer is a multiple of
+                        * 16-bytes.
+                        */
+                       if ((sc->sc_cblk[seg].cb_txfr_len & 0xf) == 0)
+                               sc->sc_cblk[seg].cb_ti |= DMAC_TI_SRC_WIDTH;
                        sc->sc_cblk[seg].cb_ti |= DMAC_TI_DEST_DREQ;
                        sc->sc_cblk[seg].cb_source_ad =
                            cmd->c_dmamap->dm_segs[seg].ds_addr;
@@ -267,8 +284,6 @@
                            BCM2835_PERIPHERALS_TO_BUS(sc->sc_physaddr +
                            SDHC_DATA);
                }
-               sc->sc_cblk[seg].cb_txfr_len =
-                   cmd->c_dmamap->dm_segs[seg].ds_len;
                sc->sc_cblk[seg].cb_stride = 0;
                if (seg == cmd->c_dmamap->dm_nsegs - 1) {
                        sc->sc_cblk[seg].cb_ti |= DMAC_TI_WAIT_RESP;