nginx cache secondary php location

gistfile1.nginxconf

fastcgi_cache_path /tmp/cache levels=1:2 keys_zone=images:100m inactive=60m;
fastcgi_cache_key "$scheme$request_method$host$request_uri";

server {
    listen 80 default_server;
    listen [::]:80 default_server ipv6only=on;

    #root /usr/share/nginx/html;
    root /var/www/html;
    index index.html index.htm;

    # Make site accessible from http://localhost/
    server_name localhost;

    location /a/ {
            fastcgi_cache images;
            fastcgi_cache_valid 200 60m; # Only cache 200 responses, cache for 60 minutes
            fastcgi_cache_methods GET HEAD; # Only GET and HEAD methods apply
            add_header X-Fastcgi-Cache $upstream_cache_status;
            #fastcgi_cache_bypass $http_cache_control;
            fastcgi_ignore_headers Set-Cookie Cache-Control Expires;

            fastcgi_pass unix:/var/run/php5-fpm.sock;
            include fastcgi_params;
            fastcgi_param SCRIPT_FILENAME /var/www/html/index.php;
            fastcgi_param PATH_INFO /a;
    }

    location / {
            # First attempt to serve request as file, then
            # as directory, then fall back to displaying a 404.
            try_files $uri $uri/ /index.php?$query_string;
            # Uncomment to enable naxsi on this location
            # include /etc/nginx/naxsi.rules
    }
    
    location ~ \.php$ {
            fastcgi_split_path_info ^(.+\.php)(/.+)$;
    #       # NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini
    #
    #       # With php5-cgi alone:
    #       fastcgi_pass 127.0.0.1:9000;
    #       # With php5-fpm:
            fastcgi_pass unix:/var/run/php5-fpm.sock;
            fastcgi_index index.php;
            include fastcgi_params;
    }
}