diff options
author | Arthur Benilov <arthur.benilov@gmail.com> | 2010-09-24 19:26:13 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-09-30 04:33:26 -0700 |
commit | 53059aa05988761a738fa8bc082bbf3c5d4462d1 (patch) | |
tree | 1d260afd6dce5e55389516d444570e4e6bc42c37 /drivers | |
parent | 0abd242839eac8437521101c9361c095728eded3 (diff) |
Staging: vme: Assure D16 cycle if required in master_read and master_write
From a95892fc2246d6dc45f57b7dd68f32b9b28bd0f7 Mon Sep 17 00:00:00 2001
From: Arthur Benilov <arthur.benilov@gmail.com>
Date: Fri, 24 Sep 2010 13:51:07 +0200
Subject: [PATCH] Staging: vme: Assure D16 cycle if required in master_read and master_write
memcpy_fromio() and memcpy_toio() functions apply internally to __memcpy() that
performs data transfer in 32-bits or 8-bits blocks (at least on x86). This makes
impossible to perform D16 cycle with ca91cx42 bridge. Provided modification
assures performing data transfer with 32, 16, and 8 bits chunks.
Signed-off-by: Arthur Benilov <arthur.benilov@iba-group.com>
Signed-off-by: Martyn Welch <martyn.welch@ge.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/staging/vme/bridges/vme_ca91cx42.c | 94 |
1 files changed, 89 insertions, 5 deletions
diff --git a/drivers/staging/vme/bridges/vme_ca91cx42.c b/drivers/staging/vme/bridges/vme_ca91cx42.c index 06bd793c52b5..4d745623211b 100644 --- a/drivers/staging/vme/bridges/vme_ca91cx42.c +++ b/drivers/staging/vme/bridges/vme_ca91cx42.c @@ -848,12 +848,57 @@ ssize_t ca91cx42_master_read(struct vme_master_resource *image, void *buf, size_t count, loff_t offset) { ssize_t retval; + void *addr = image->kern_base + offset; + unsigned int done = 0; + unsigned int count32; + + if (count == 0) + return 0; spin_lock(&(image->lock)); - memcpy_fromio(buf, image->kern_base + offset, (unsigned int)count); - retval = count; + /* The following code handles VME address alignment problem + * in order to assure the maximal data width cycle. + * We cannot use memcpy_xxx directly here because it + * may cut data transfer in 8-bits cycles, thus making + * D16 cycle impossible. + * From the other hand, the bridge itself assures that + * maximal configured data cycle is used and splits it + * automatically for non-aligned addresses. + */ + if ((int)addr & 0x1) { + *(u8 *)buf = ioread8(addr); + done += 1; + if (done == count) + goto out; + } + if ((int)addr & 0x2) { + if ((count - done) < 2) { + *(u8 *)(buf + done) = ioread8(addr + done); + done += 1; + goto out; + } else { + *(u16 *)(buf + done) = ioread16(addr + done); + done += 2; + } + } + count32 = (count - done) & ~0x3; + if (count32 > 0) { + memcpy_fromio(buf + done, addr + done, (unsigned int)count); + done += count32; + } + + if ((count - done) & 0x2) { + *(u16 *)(buf + done) = ioread16(addr + done); + done += 2; + } + if ((count - done) & 0x1) { + *(u8 *)(buf + done) = ioread8(addr + done); + done += 1; + } +out: + retval = count; spin_unlock(&(image->lock)); return retval; @@ -862,15 +907,54 @@ ssize_t ca91cx42_master_read(struct vme_master_resource *image, void *buf, ssize_t ca91cx42_master_write(struct vme_master_resource *image, void *buf, size_t count, loff_t offset) { - int retval = 0; + ssize_t retval; + void *addr = image->kern_base + offset; + unsigned int done = 0; + unsigned int count32; + + if (count == 0) + return 0; spin_lock(&(image->lock)); - memcpy_toio(image->kern_base + offset, buf, (unsigned int)count); + /* Here we apply for the same strategy we do in master_read + * function in order to assure D16 cycle when required. + */ + if ((int)addr & 0x1) { + iowrite8(*(u8 *)buf, addr); + done += 1; + if (done == count) + goto out; + } + if ((int)addr & 0x2) { + if ((count - done) < 2) { + iowrite8(*(u8 *)(buf + done), addr + done); + done += 1; + goto out; + } else { + iowrite16(*(u16 *)(buf + done), addr + done); + done += 2; + } + } + + count32 = (count - done) & ~0x3; + if (count32 > 0) { + memcpy_toio(addr + done, buf + done, count32); + done += count32; + } + + if ((count - done) & 0x2) { + iowrite16(*(u16 *)(buf + done), addr + done); + done += 2; + } + if ((count - done) & 0x1) { + iowrite8(*(u8 *)(buf + done), addr + done); + done += 1; + } +out: retval = count; spin_unlock(&(image->lock)); - return retval; } |