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i2c: increase BUFLEN/CMDLEN to 128, add page flag.

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128 byte reads are much more common than 32 byte reads. The message
passing + setup/teardown for a read is much more expensive, in terms
of time, than the reading itself. A slightly bigger struct is well
worth the time savings. This reduces read times for /dev/eeprom
from 57 seconds per 4KB to 14 seconds.

Additionally, make sending the page address in the eeprom driver
and utility optional. This can save a little time when reading
within the same page and allows support for smaller devices that
don't support pages (example: chips containing EDID).

Change-Id: Ie48087caee40c11fa241d1555fce9309ddd27b43
This commit is contained in:
Thomas Cort
2013-07-26 19:44:52 -04:00
parent 11be35a165
commit 437177b028
7 changed files with 94 additions and 59 deletions
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68
drivers/cat24c256/cat24c256.c
View File

@@ -1,4 +1,5 @@
#include <minix/blockdriver.h>
#include <minix/com.h>
#include <minix/drivers.h>
#include <minix/ds.h>
#include <minix/i2c.h>
@@ -53,10 +54,10 @@ struct blockdriver cat24c256_tab = {
.bdr_device = NULL /* 1 insance per bus, threads not needed */
};
static int cat24c256_read32(uint16_t memaddr, void *buf, size_t buflen);
static int cat24c256_read(uint16_t memaddr, void *buf, size_t buflen);
static int cat24c256_write16(uint16_t memaddr, void *buf, size_t buflen);
static int cat24c256_write(uint16_t memaddr, void *buf, size_t buflen);
static int cat24c256_read128(uint16_t memaddr, void *buf, size_t buflen, int flags);
static int cat24c256_read(uint16_t memaddr, void *buf, size_t buflen, int flags);
static int cat24c256_write16(uint16_t memaddr, void *buf, size_t buflen, int flags);
static int cat24c256_write(uint16_t memaddr, void *buf, size_t buflen, int flags);
/* globals */
@@ -176,13 +177,13 @@ cat24c256_blk_transfer(dev_t minor, int do_write, u64_t pos64,
return EINVAL;
}
r = cat24c256_write(position, copybuf, count);
r = cat24c256_write(position, copybuf, count, flags);
if (r != OK) {
log_warn(&log, "write failed (r=%d)\n", r);
return r;
}
} else {
r = cat24c256_read(position, copybuf, count);
r = cat24c256_read(position, copybuf, count, flags);
if (r != OK) {
log_warn(&log, "read failed (r=%d)\n", r);
return r;
@@ -259,16 +260,16 @@ cat24c256_blk_other(message * m)
return r;
}
/* The lower level i2c interface can only read/write 32 bytes at a time.
/* The lower level i2c interface can only read/write 128 bytes at a time.
* One might want to do more I/O than that at once w/EEPROM, so there is
* cat24c256_read() and cat24c256_read32(). cat24c256_read32() does the
* actual reading in chunks up to 32 bytes. cat24c256_read() splits
* the request up into chunks and repeatedly calls cat24c256_read32()
* cat24c256_read() and cat24c256_read128(). cat24c256_read128() does the
* actual reading in chunks up to 128 bytes. cat24c256_read() splits
* the request up into chunks and repeatedly calls cat24c256_read128()
* until all of the requested EEPROM locations have been read.
*/
static int
cat24c256_read32(uint16_t memaddr, void *buf, size_t buflen)
cat24c256_read128(uint16_t memaddr, void *buf, size_t buflen, int flags)
{
int r;
minix_i2c_ioctl_exec_t ioctl_exec;
@@ -286,9 +287,15 @@ cat24c256_read32(uint16_t memaddr, void *buf, size_t buflen)
ioctl_exec.iie_addr = address;
/* set the memory address to read from */
ioctl_exec.iie_cmd[0] = ((memaddr >> 8) & 0xff);
ioctl_exec.iie_cmd[1] = (memaddr & 0xff);
ioctl_exec.iie_cmdlen = 2;
if ((BDEV_NOPAGE & flags) == BDEV_NOPAGE) {
/* reading within the current page */
ioctl_exec.iie_cmd[0] = (memaddr & 0xff);
ioctl_exec.iie_cmdlen = 1;
} else {
ioctl_exec.iie_cmd[0] = ((memaddr >> 8) & 0xff);
ioctl_exec.iie_cmd[1] = (memaddr & 0xff);
ioctl_exec.iie_cmdlen = 2;
}
ioctl_exec.iie_buflen = buflen;
@@ -307,7 +314,7 @@ cat24c256_read32(uint16_t memaddr, void *buf, size_t buflen)
}
int
cat24c256_read(uint16_t memaddr, void *buf, size_t buflen)
cat24c256_read(uint16_t memaddr, void *buf, size_t buflen, int flags)
{
int r;
uint16_t i;
@@ -317,25 +324,26 @@ cat24c256_read(uint16_t memaddr, void *buf, size_t buflen)
return -1;
}
for (i = 0; i < buflen; i += 32) {
for (i = 0; i < buflen; i += 128) {
r = cat24c256_read32(memaddr + i, buf + i,
((buflen - i) < 32) ? (buflen - i) : 32);
r = cat24c256_read128(memaddr + i, buf + i,
((buflen - i) < 128) ? (buflen - i) : 128, flags);
if (r != OK) {
return r;
}
log_trace(&log, "read %d bytes starting at 0x%x\n",
((buflen - i) < 32) ? (buflen - i) : 32, memaddr + i);
((buflen - i) < 128) ? (buflen - i) : 128, memaddr + i);
}
return OK;
}
static int
cat24c256_write16(uint16_t memaddr, void *buf, size_t buflen)
cat24c256_write16(uint16_t memaddr, void *buf, size_t buflen, int flags)
{
int r;
int addrlen;
minix_i2c_ioctl_exec_t ioctl_exec;
if (buflen > (I2C_EXEC_MAX_BUFLEN - 2) || buf == NULL
@@ -352,11 +360,17 @@ cat24c256_write16(uint16_t memaddr, void *buf, size_t buflen)
ioctl_exec.iie_cmdlen = 0;
/* set the memory address to write to */
ioctl_exec.iie_buf[0] = ((memaddr >> 8) & 0xff);
ioctl_exec.iie_buf[1] = (memaddr & 0xff);
memcpy(ioctl_exec.iie_buf + 2, buf, buflen);
ioctl_exec.iie_buflen = buflen + 2;
if ((BDEV_NOPAGE & flags) == BDEV_NOPAGE) {
/* writing within the current page */
ioctl_exec.iie_buf[0] = (memaddr & 0xff); /* address */
addrlen = 1;
} else {
ioctl_exec.iie_buf[0] = ((memaddr >> 8) & 0xff);/* page */
ioctl_exec.iie_buf[1] = (memaddr & 0xff); /* address */
addrlen = 2;
}
memcpy(ioctl_exec.iie_buf + addrlen, buf, buflen);
ioctl_exec.iie_buflen = buflen + addrlen;
r = i2cdriver_exec(bus_endpoint, &ioctl_exec);
if (r != OK) {
@@ -371,7 +385,7 @@ cat24c256_write16(uint16_t memaddr, void *buf, size_t buflen)
}
int
cat24c256_write(uint16_t memaddr, void *buf, size_t buflen)
cat24c256_write(uint16_t memaddr, void *buf, size_t buflen, int flags)
{
int r;
uint16_t i;
@@ -384,7 +398,7 @@ cat24c256_write(uint16_t memaddr, void *buf, size_t buflen)
for (i = 0; i < buflen; i += 16) {
r = cat24c256_write16(memaddr + i, buf + i,
((buflen - i) < 16) ? (buflen - i) : 16);
((buflen - i) < 16) ? (buflen - i) : 16, flags);
if (r != OK) {
return r;
}