What was found
FLT 520 - PHX - RNO - FL380, CREW RECEIVED ECAM INDICATION FOR NR 2 ENGINE AIR BLEED FAULT. PILOT OPENED CROSS BLEED VALVE WHICH RESULTED IN NR 1 BLEED FAULT CAUSING BOTH PACKS TO FAIL. CABIN PRESSURE CLIMBING 500'/MIN. DESCENDED TO 12000' WITH BOTH BLEED VALVES SHOWING CLOSED. PUT CROSS BLEED BACK TO AUTO RESTORING NR 2 ENGINE BLEED AND PRESSURIZATION. ECAM INDICATED 'CAB PRESS SYS 2' FAULT. CREW DECLARED AN EMERGENCY INTO RNO AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED NR 1 AND NR 2 ENGINE FAN AIR VALVES AND BOTH TEMPERATURE CONTROL THERMOSTATS.