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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>
This commit is contained in:
Arthur Benilov 2010-09-24 19:26:13 +02:00 committed by Greg Kroah-Hartman
parent 0abd242839
commit 53059aa059
1 changed files with 89 additions and 5 deletions
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94
drivers/staging/vme/bridges/vme_ca91cx42.c
View File

@ -848,12 +848,57 @@ ssize_t ca91cx42_master_read(struct vme_master_resource *image, void *buf,
size_t count, loff_t offset) size_t count, loff_t offset)
{ {
ssize_t retval; 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)); spin_lock(&(image->lock));
memcpy_fromio(buf, image->kern_base + offset, (unsigned int)count); /* The following code handles VME address alignment problem
retval = count; * 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)); spin_unlock(&(image->lock));
return retval; 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, ssize_t ca91cx42_master_write(struct vme_master_resource *image, void *buf,
size_t count, loff_t offset) 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)); 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; retval = count;
spin_unlock(&(image->lock)); spin_unlock(&(image->lock));
return retval; return retval;
} }