| # SPDX-License-Identifier: GPL-2.0-only |
| comment "Processor Features" |
| |
| config CPU_BIG_ENDIAN |
| def_bool !CPU_LITTLE_ENDIAN |
| |
| config CPU_LITTLE_ENDIAN |
| bool "Little endian" |
| default y |
| |
| config FPU |
| bool "FPU support" |
| default n |
| help |
| If FPU ISA is used in user space, this configuration shall be Y to |
| enable required support in kernel such as fpu context switch and |
| fpu exception handler. |
| |
| If no FPU ISA is used in user space, say N. |
| |
| config LAZY_FPU |
| bool "lazy FPU support" |
| depends on FPU |
| default y |
| help |
| Say Y here to enable the lazy FPU scheme. The lazy FPU scheme can |
| enhance system performance by reducing the context switch |
| frequency of the FPU register. |
| |
| For normal case, say Y. |
| |
| config SUPPORT_DENORMAL_ARITHMETIC |
| bool "Denormal arithmetic support" |
| depends on FPU |
| default n |
| help |
| Say Y here to enable arithmetic of denormalized number. Enabling |
| this feature can enhance the precision for tininess number. |
| However, performance loss in float point calculations is |
| possibly significant due to additional FPU exception. |
| |
| If the calculated tolerance for tininess number is not critical, |
| say N to prevent performance loss. |
| |
| config HWZOL |
| bool "hardware zero overhead loop support" |
| depends on CPU_D10 || CPU_D15 |
| default n |
| help |
| A set of Zero-Overhead Loop mechanism is provided to reduce the |
| instruction fetch and execution overhead of loop-control instructions. |
| It will save 3 registers($LB, $LC, $LE) for context saving if say Y. |
| You don't need to save these registers if you can make sure your user |
| program doesn't use these registers. |
| |
| If unsure, say N. |
| |
| config CPU_CACHE_ALIASING |
| bool "Aliasing cache" |
| depends on CPU_N10 || CPU_D10 || CPU_N13 || CPU_V3 |
| default y |
| help |
| If this CPU is using VIPT data cache and its cache way size is larger |
| than page size, say Y. If it is using PIPT data cache, say N. |
| |
| If unsure, say Y. |
| |
| choice |
| prompt "minimum CPU type" |
| default CPU_V3 |
| help |
| The data cache of N15/D15 is implemented as PIPT and it will not cause |
| the cache aliasing issue. The rest cpus(N13, N10 and D10) are |
| implemented as VIPT data cache. It may cause the cache aliasing issue |
| if its cache way size is larger than page size. You can specify the |
| CPU type directly or choose CPU_V3 if unsure. |
| |
| A kernel built for N10 is able to run on N15, D15, N13, N10 or D10. |
| A kernel built for N15 is able to run on N15 or D15. |
| A kernel built for D10 is able to run on D10 or D15. |
| A kernel built for D15 is able to run on D15. |
| A kernel built for N13 is able to run on N15, N13 or D15. |
| |
| config CPU_N15 |
| bool "AndesCore N15" |
| config CPU_N13 |
| bool "AndesCore N13" |
| select CPU_CACHE_ALIASING if ANDES_PAGE_SIZE_4KB |
| config CPU_N10 |
| bool "AndesCore N10" |
| select CPU_CACHE_ALIASING |
| config CPU_D15 |
| bool "AndesCore D15" |
| config CPU_D10 |
| bool "AndesCore D10" |
| select CPU_CACHE_ALIASING |
| config CPU_V3 |
| bool "AndesCore v3 compatible" |
| select CPU_CACHE_ALIASING |
| endchoice |
| choice |
| prompt "Paging -- page size " |
| default ANDES_PAGE_SIZE_4KB |
| config ANDES_PAGE_SIZE_4KB |
| bool "use 4KB page size" |
| config ANDES_PAGE_SIZE_8KB |
| bool "use 8KB page size" |
| endchoice |
| |
| config CPU_ICACHE_DISABLE |
| bool "Disable I-Cache" |
| help |
| Say Y here to disable the processor instruction cache. Unless |
| you have a reason not to or are unsure, say N. |
| |
| config CPU_DCACHE_DISABLE |
| bool "Disable D-Cache" |
| help |
| Say Y here to disable the processor data cache. Unless |
| you have a reason not to or are unsure, say N. |
| |
| config CPU_DCACHE_WRITETHROUGH |
| bool "Force write through D-cache" |
| depends on !CPU_DCACHE_DISABLE |
| help |
| Say Y here to use the data cache in writethrough mode. Unless you |
| specifically require this or are unsure, say N. |
| |
| config WBNA |
| bool "WBNA" |
| default n |
| help |
| Say Y here to enable write-back memory with no-write-allocation policy. |
| |
| config ALIGNMENT_TRAP |
| bool "Kernel support unaligned access handling by sw" |
| depends on PROC_FS |
| default n |
| help |
| Andes processors cannot load/store information which is not |
| naturally aligned on the bus, i.e., a 4 byte load must start at an |
| address divisible by 4. On 32-bit Andes processors, these non-aligned |
| load/store instructions will be emulated in software if you say Y |
| here, which has a severe performance impact. With an IP-only |
| configuration it is safe to say N, otherwise say Y. |
| |
| config HW_SUPPORT_UNALIGNMENT_ACCESS |
| bool "Kernel support unaligned access handling by hw" |
| depends on !ALIGNMENT_TRAP |
| default n |
| help |
| Andes processors load/store world/half-word instructions can access |
| unaligned memory locations without generating the Data Alignment |
| Check exceptions. With an IP-only configuration it is safe to say N, |
| otherwise say Y. |
| |
| config HIGHMEM |
| bool "High Memory Support" |
| depends on MMU && !CPU_CACHE_ALIASING |
| select KMAP_LOCAL |
| help |
| The address space of Andes processors is only 4 Gigabytes large |
| and it has to accommodate user address space, kernel address |
| space as well as some memory mapped IO. That means that, if you |
| have a large amount of physical memory and/or IO, not all of the |
| memory can be "permanently mapped" by the kernel. The physical |
| memory that is not permanently mapped is called "high memory". |
| |
| Depending on the selected kernel/user memory split, minimum |
| vmalloc space and actual amount of RAM, you may not need this |
| option which should result in a slightly faster kernel. |
| |
| If unsure, say N. |
| |
| config CACHE_L2 |
| bool "Support L2 cache" |
| default y |
| help |
| Say Y here to enable L2 cache if your SoC are integrated with L2CC. |
| If unsure, say N. |
| |
| config HW_PRE |
| bool "Enable hardware prefetcher" |
| default y |
| help |
| Say Y here to enable hardware prefetcher feature. |
| Only when CPU_VER.REV >= 0x09 can support. |
| |
| menu "Memory configuration" |
| |
| choice |
| prompt "Memory split" |
| depends on MMU |
| default VMSPLIT_3G_OPT |
| help |
| Select the desired split between kernel and user memory. |
| |
| If you are not absolutely sure what you are doing, leave this |
| option alone! |
| |
| config VMSPLIT_3G |
| bool "3G/1G user/kernel split" |
| config VMSPLIT_3G_OPT |
| bool "3G/1G user/kernel split (for full 1G low memory)" |
| config VMSPLIT_2G |
| bool "2G/2G user/kernel split" |
| config VMSPLIT_1G |
| bool "1G/3G user/kernel split" |
| endchoice |
| |
| config PAGE_OFFSET |
| hex |
| default 0x40000000 if VMSPLIT_1G |
| default 0x80000000 if VMSPLIT_2G |
| default 0xB0000000 if VMSPLIT_3G_OPT |
| default 0xC0000000 |
| |
| endmenu |