[PATCH RFC] Upstream A64FX cache driver

[tan.shaopeng]

From: "tan.shaopeng" <tan.shaopeng at jp.fujitsu.com>

Hello, 

This driver enables Fujitsu A64FX's cache function. 

[Driver Description] 
A64FX CPU has several functions for HPC workload and this driver is  
for cache functions. 

Loading this cache driver, control registers will be set to enable  
these functions, and advanced settings registers will be set by default 
values. After loading this driver, you can use the default values of the 
advanced settings registers or set custom values to the advanced 
settings registers from EL0. Unloading this driver, control registers 
will be clear to disable these functions. 

These functions include sector cache function and hardware prefetch  
assistance function. 
- Sector cache function:  
 Cache partitioning function which can control virtual cache capacity for 
 each characteristics of data such as temporal locality. 
- Hardware prefetch assistance function:  
 Software can provide the hint for hardware prefetch mechanism to reduce  
 the penalty of the memory access. By providing the access pattern  
 through that function in advance, hardware prefetch mechanism can access 
 the complex pattern. 

These functions can be executed according to the default values of the 
registers which are set by the driver. Or they can be executed  
according to a tag which is the upper 8 bits of the load/store address 
of application to customize hardware prefetch and sector cache. 

For more details of these functions,  
see A64FX HPC extension specification in 
https://github.com/fujitsu/A64FX  

The driver is based on v5.11-rc2 and tested on FX1000 environment. 

[RFC]  
This function only performs register initialization for A64FX. At first, 
I wanted to insert it to kernel initialization code, but there is no  
initialization code except errata, so I made this driver. 
I'd like to know if this approach is OK? Would you give me some advice? 

Best regards, 
Tan Shaopeng 

tan.shaopeng (1):
  soc: fujitsu: Add cache driver code

 MAINTAINERS                         |   6 ++
 arch/arm64/Kconfig.platforms        |   5 +
 drivers/soc/Kconfig                 |   1 +
 drivers/soc/Makefile                |   1 +
 drivers/soc/fujitsu/Kconfig         |  26 +++++
 drivers/soc/fujitsu/fujitsu_cache.c | 183 ++++++++++++++++++++++++++++++++++++
 6 files changed, 222 insertions(+)
 create mode 100644 drivers/soc/fujitsu/Kconfig
 create mode 100644 drivers/soc/fujitsu/fujitsu_cache.c

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1.8.3.1