
4/29/2020
Loongson 3A3000 / 3B3000 Processor User Manual
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1. Modify the Cache description structure in the kernel. Both VCache and SCache are connected by a 16-way group; (same as 3A2000)
2. Modify the calculation method of the temperature sensor, the algorithm is: junction temperature = Thens_out * 731 / 0x4000-273;
3. Modify the configuration register address when shutting down the core; (same as 3A2000)
4. Change the operation of flashing ICache / DCache to flashing ICache / DCache / VCache; (same as 3A2000)
5. If an SPI controller is used, the base address is changed from 0xBFE001F0 to 0xBFE00220; (same as 3A2000)
6. Uncache DMA must be used, and the data consistency of Cache must be maintained by software; (consistent with 3A2000)
7. Add store fill buffer support: One is to add a SYNC before all Uncache requests to ensure
When the Uncache request occurs, the contents of the store fill buffer have been written back to the Cache; the second is that all
The unlock operation in the synchronous operation shared among different cores is implemented using LL / SC instructions. (Consistent with 3A2000)
8. Do not use the MSI function of the device. When you must use the MSI function, you need to transfer the data of the POST channel of the HT controller
Set the number of receive buffers to 1 and reconnect to the HT bus; (same as 3A2000)
9. Lock Cache operations cannot be used for DMA areas where hardware automatically maintains consistency. (Consistent with 3A2000)
Modifications that can also be used to improve performance are:
1. Increase support for FTLB; (consistent with 3A2000)
2. Add support for TLB fast refill; (consistent with 3A2000)
3. Add support for wait command; (consistent with 3A2000)
4. Add support for prefetch instructions; (consistent with 3A2000)
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Godson 3A3000 / 3B3000 Processor User Manual • Volume 1
5. Use DI / EI to implement interrupt return. But it should be noted that the [31: 4] returned by the EI instruction is a random value, which is different from the MIPS
Differences. (Consistent with 3A2000)