tree b642522bae84b0b93fa9dbed1e0a10de3b2dfe4d
parent f05effdb612c2ffdc625f52a28cd7ff2ea0ea401
author PriyangaRamasamy <priyanga24@in.ibm.com> 1599564799 +0530
committer Santosh Puranik <santosh.puranik@in.ibm.com> 1620634764 +0530

Translate Udev Event path to a generic path

Given Udev event generated path is translated into sys bus path - as the json will
have the sys/bus path.

Test:
-> Translation successful for all frus including frus behind muxes.
-> If the system vpd is triggered by udev event, then the execution stops as
the system vpd will already be parsed via system-vpd.service.

Few Reasons why we translate the path to a generic path:
	-> Each i2c bus is memory mapped to a certain address in ASPEED.
	   In future if there are any architectural changes in the kernel, we need to
	   make changes to the JSON accordingly.
	-> Also in future if the system runs on a different ASPEED, we need to
	   update the JSON accordingly.
	-> This generic /sys/bus path represents the system wiring and doesnot rely on
	   how the busses are memory mapped.
	-> Also for call out based events, generic path is expected than the udev event path.

Sample Udev Event i2c path : "/sys/devices/platform/ahb/ahb:apb/ahb:apb:bus@1e78a000/1e78a480.i2c-bus/i2c-8/8-0050/8-00500/nvmem"
Which gets translated to /sys/bus/ path as : "/sys/bus/i2c/drivers/at24/8-0050/eeprom"

Sample Udev Event spi path : "/sys/devices/platform/ahb/ahb:apb/1e79b000.fsi/fsi-master/fsi0/slave@00:00/00:00:00:0a/fsi-master/fsi1/slave@03:00/01:03:00:04/spi_master/spi6/spi6.0/spi6.00/nvmem"
Which gets translated to /sys/bus/ path as : "/sys/bus/spi/drivers/at25/spi6.0/eeprom"

Sample Udev Event i2c path for frus behind mux : "/sys/devices/platform/ahb/ahb:apb/ahb:apb:bus@1e78a000/1e78a300.i2c-bus/i2c-5/i2c-24/24-0051/24-00510/nvmem"
Which gets translated to generic path as /sys/bus/i2c/drivers/at24/24-0051/eeprom

Tested on simics:

<the inventory json should have generic eeprom paths for all frus>

root@rainier:/tmp# ./ibm-read-vpd-UG -f /sys/devices/platform/ahb/ahb:apb/1e79b000.fsi/fsi-master/fsi0/slave@00:00/00:00:00:04/spi_master/spi12/spi12.0/spi12.00/nvmem
the path after translation : /sys/bus/spi/drivers/at25/spi12.0/eeprom

root@rainier:/tmp# ./ibm-read-vpd-UG -f /sys/devices/platform/ahb/ahb:apb/ahb:apb:bus@1e78a000/1e78a480.i2c-bus/i2c-8/8-0051/8-00510/nvmem
the path after translation : /sys/bus/i2c/drivers/at24/8-0051/eeprom

root@rainier:/tmp# ./ibm-read-vpd-UG -f /sys/bus/i2c/drivers/at24/8-0051/8-00510/nvmem
the path after translation : /sys/bus/i2c/drivers/at24/8-0051/eeprom

Signed-off-by: PriyangaRamasamy <priyanga24@in.ibm.com>
Change-Id: I6d5995a85ef15e63d2d0b6f054fb0bf14a2b756c