Sony CXD5602 User Manual page 924

3.13.4.14 Bus Matrix
APP_DSP has two multi-layer AHB matrixes. APP MAIN Bus matrix uses a processor as a master, and has
SRAM with protection features as a slave. APP SUB Bus matrix has a connection interface for three sub blocks:
PWD_APP_AUD, APP_IMG, and APP_PER mainly used for PWD_APP, and has data of each functional block
inside APP_DSP and control interface. Figure APP-104 shows the connection overview.
Only when simultaneous accesses to a single slave occurs, arbitration operates according to the multi-layer AHB
matrix. The algorithm of the arbitration is round-robin.
3.13.4.15 Exclusive Load/Store
Monitoring and controlling of exclusive accesses to slaves are performed.
One monitoring of access per APP SRAM tile (12 in total) and one monitoring of access from APP MAIN Bus to
APP SUB Bus are performed.
By setting the register, this function can be enabled or disabled.
When BUS_SNOOP_DISABLE.bus_snoop_disable = 1'b1, all accesses receive "success" response.
Switch BUS_SNOOP_DISABLE at the timing when LDREX/STREX is ensured not to be issued. In the case
that it was switched while LDREX or STREX are in use, the snooping of the Bus will be finished.
When BUS_SNOOP_DISABLE.bus_snoop_disable = 1'b1, Bus Snooper is reset. Held status is cleared. (Only
internal flag is cleared.)
Address Register Name
0x0E013000 BUS_SNOOP_DIS
ABLE
3.13.4.15.1 Monitoring Exclusive Accesses to SRAM
The following shows the features of monitoring exclusive accesses to SRAM.

In the case that there is an exclusive read (ExR), the address will be snooped.

Only first address per APP SRAM tile can be snooped. Until the snooping of the first address is released, the
second and subsequent exclusive reads (ExRs) are ignored. In addition, only one master can obtain the
exclusive access right.

The target address of monitoring must be Word address. When monitoring an exclusive access, the data
monitor size is word even if the data access size is any of byte, halfword, or word.
Table APP-759 Exclusive Access Register
Bit Field Name Type
bus_snoop_disable RW
－924/1010－
Bit Initial Description
Value
[0] 1 Exclusive Load/Store Disable register
1: Disable
0: Enable
CXD5602 User Manual