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White Rabbit Switch - Software
Commit 579646e4 authored by Paul Boven's avatar Paul Boven Committed by Adam Wujek
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userspace/libwr: Fixes to make shw_write_sfp() actually write SFP eeproms 

The SFP documentation "INF-8047.pdf" states:
"The serial interface uses the 2-wire serial CMOS E2PROM protocol defined for
the ATMEL AT24C01A/02/04 family of components."

Upon reading that datasheet, some important details stand out:
1) The eeprom can only write in pages, with pages being 8 or 16 bytes. Assuming
   the smallest device, you can only write 8 bytes at a time. To be safe, I'm
   assuming a pagesize of 8 bytes.

   This explains why we only saw stuff change in the first 8 bytes, I guess.

2) A write needs to be preceded by the byte address which is a single byte for
   these devices, and then up to 8 (or 16) data bytes to be written at that
   location. If there are more bytes, or if the data wraps around the page
   binary, it will still only end up on the page belonging to that first
   address.

3) After writing, you need to poll the eeprom to see if it has finished writing
   the byte. At the moment, I'm not doing that yet, instead I'm doing a 10ms
   wait which seems sufficient.
Signed-off-by: Paul Boven's avatarPaul Boven <boven@jive.eu>
Acked-by: Adam Wujek's avatarAdam Wujek <adam.wujek@cern.ch>
parent 3f05b29c
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Showing with 52 additions and 5 deletions
userspace/libwr/i2c_sfp.c
View file @ 579646e4
......@@ -47,6 +47,9 @@
#define SFP_LED_WRMODE_MASK(t) ((t) ? (1 << 5) : (1 << 3))
#define SFP_TX_DISABLE_MASK(t) ((t) ? (1 << 7) : (1 << 2))
/* Either 8 or 16 byte pages, so we use the smaller */
#define SFP_PAGE_SIZE 8
/*
* We need these tables because the schematics are messed up
* The first one is for figuring out the masks in the pca9548's
......@@ -392,15 +395,26 @@ int32_t shw_sfp_read(int num, uint32_t addr, int off, int len, uint8_t * buf)
return i2c_transfer(bus, addr, 0, len, buf);
}
int32_t shw_sfp_write(int num, uint32_t addr, int off, int len, uint8_t * buf)
{
int id;
uint8_t byte1, byte2;
int32_t counter = 0;
struct i2c_bus *bus;
int i = 0;
uint8_t page[SFP_PAGE_SIZE + 1];
int ret;
/* The SFP eeprom only supports 8 bit addresses */
if (len < 1 || len > 256 || off < 0 || off > 256 || off + len < 0
|| off + len > 256)
return -1;
id = shw_sfp_id(num);
if (id < 0)
return -1;
bus = &i2c_buses[WR_MUX_BUS];
if (id == 0 || id == 1)
bus = &i2c_buses[WR_SFP0_BUS + id];
......@@ -413,11 +427,44 @@ int32_t shw_sfp_write(int num, uint32_t addr, int off, int len, uint8_t * buf)
i2c_transfer(bus, 0x71, 1, 0, &byte2);
}
/* Send the offset we want to write to if requested */
if (off >= 0)
i2c_transfer(bus, addr, 1, 0, (uint8_t *) & off);
/* Do the read */
return i2c_transfer(bus, addr, len, 0, buf);
/* Write in a paged mode, 1 byte address */
page[0] = (counter + off) & 0xff;
while (counter < len)
{
page[i + 1] = buf[counter++];
i++;
/* When we hit a page boundary then perform a write */
if ((off + counter) % SFP_PAGE_SIZE == 0)
{
pr_debug("Writing %d bytes to EEPROM address %02x\n",
i, page[0]);
ret = i2c_transfer(bus, addr, i + 1, 0, page);
if (ret < 0) {
pr_error("i2c_transfer error code 0x%x\n",
ret);
return -1;
}
i = 0;
page[0] = (counter + off) & 0xff;
/* Sleep 10ms for eeprom to finish writing the page */
/* XXX this should actually be done by polling the */
/* EEPROM and seeing if it is ready */
usleep(10000);
}
}
/* Write the last page, if not already done */
if (i != 0)
{
pr_debug("Writing last %d bytes to EEPROM address %02x\n",
i, page[0]);
ret = i2c_transfer(bus, addr, i + 1, 0, page);
if (ret < 0) {
pr_error("i2c_transfer error code 0x%x\n", ret);
return -1;
}
usleep(10000);
}
return counter;
}
uint32_t shw_sfp_module_scan(void)
......
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