Loongarch32 Linux phys virt address
现在是到这了，问题是__request_resource第2个参数地址有问题，0xa2800000。物理内存从dtb里写的就是从0x2800000开始，前面的a是多出来的。
这个第二个参数是memblock_alloc()分配出来的。
for_each_mem_range(i, &start, &end) {
struct resource *res;
res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
if (!res)
panic("%s: Failed to allocate %zu bytes\n", __func__,
sizeof(struct resource));
res->start = start;
/*
* In memblock, end points to the first byte after the
* range while in resourses, end points to the last byte in
* the range.
*/
res->end = end - 1;
res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
res->name = "System RAM";
printk("!!!!request_resource\n");
request_resource(&iomem_resource, res);
/*
* We don't know which RAM region contains kernel data,
* so we try it repeatedly and let the resource manager
* test it.
*/
printk("!!!!request_resource\n");
request_resource(res, &code_resource);
printk("!!!!request_resource\n");
request_resource(res, &data_resource);
printk("!!!!request_resource\n");
request_resource(res, &bss_resource);
}
static __always_inline void *memblock_alloc(phys_addr_t size, phys_addr_t align)
{
return memblock_alloc_try_nid(size, align, MEMBLOCK_LOW_LIMIT,
MEMBLOCK_ALLOC_ACCESSIBLE, NUMA_NO_NODE);
}
void * __init memblock_alloc_try_nid(
phys_addr_t size, phys_addr_t align,
phys_addr_t min_addr, phys_addr_t max_addr,
int nid)
{
void *ptr;
memblock_dbg("%s: %llu bytes align=0x%llx nid=%d from=%pa max_addr=%pa %pS\n",
__func__, (u64)size, (u64)align, nid, &min_addr,
&max_addr, (void *)_RET_IP_);
ptr = memblock_alloc_internal(size, align,
min_addr, max_addr, nid, false);
if (ptr)
memset(ptr, 0, size);
return ptr;
}
static void * __init memblock_alloc_internal(
phys_addr_t size, phys_addr_t align,
phys_addr_t min_addr, phys_addr_t max_addr,
int nid, bool exact_nid)
{
phys_addr_t alloc;
/*
* Detect any accidental use of these APIs after slab is ready, as at
* this moment memblock may be deinitialized already and its
* internal data may be destroyed (after execution of memblock_free_all)
*/
if (WARN_ON_ONCE(slab_is_available()))
return kzalloc_node(size, GFP_NOWAIT, nid);
if (max_addr > memblock.current_limit)
max_addr = memblock.current_limit;
alloc = memblock_alloc_range_nid(size, align, min_addr, max_addr, nid,
exact_nid);
/* retry allocation without lower limit */
if (!alloc && min_addr)
alloc = memblock_alloc_range_nid(size, align, 0, max_addr, nid,
exact_nid);
if (!alloc)
return NULL;
return phys_to_virt(alloc);
}
跟到这出现了phys_to_virt()
/*
* Change virtual addresses to physical addresses and vv.
* These are pretty trivial
*/
#ifndef virt_to_phys
#define virt_to_phys virt_to_phys
static inline unsigned long virt_to_phys(volatile void *address)
{
return __pa((unsigned long)address);
}
#endif
#ifndef phys_to_virt
#define phys_to_virt phys_to_virt
static inline void *phys_to_virt(unsigned long address)
{
return __va(address);
}
#endif
/*
* __pa()/__va() should be used only during mem init.
*/
#define __pa(x) PHYSADDR(x)
#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET - PHYS_OFFSET))
/*
* This handles the memory map.
*/
#ifndef PAGE_OFFSET
#define PAGE_OFFSET (CAC_BASE + PHYS_OFFSET)
#endif
#ifndef IO_BASE
#define IO_BASE CSR_DMW0_BASE
#endif
#ifndef CAC_BASE
#define CAC_BASE CSR_DMW1_BASE
#endif
#ifndef UNCAC_BASE
#define UNCAC_BASE CSR_DMW0_BASE
#endif
CAC应该是cache的意思，UNCAC就是un-cache。
/* Direct Map window 0/1 */
#ifdef CONFIG_64BIT
#define CSR_DMW0_PLV0 _CONST64_(1 << 0)
#define CSR_DMW0_VSEG _CONST64_(0x8000)
#define CSR_DMW0_BASE (CSR_DMW0_VSEG << DMW_PABITS)
#define CSR_DMW0_INIT (CSR_DMW0_BASE | CSR_DMW0_PLV0)
#define CSR_DMW1_PLV0 _CONST64_(1 << 0)
#define CSR_DMW1_MAT _CONST64_(1 << 4)
#define CSR_DMW1_VSEG _CONST64_(0x9000)
#define CSR_DMW1_BASE (CSR_DMW1_VSEG << DMW_PABITS)
#define CSR_DMW1_INIT (CSR_DMW1_BASE | CSR_DMW1_MAT | CSR_DMW1_PLV0)
#else
#define CSR_DMW0_PLV0 _ULCAST_(1 << 0)
#define CSR_DMW0_VSEG _ULCAST_(0x8)
#define CSR_DMW0_BASE (CSR_DMW0_VSEG << DMW_PABITS)
#define CSR_DMW0_INIT (CSR_DMW0_BASE | CSR_DMW0_PLV0)
#define CSR_DMW1_PLV0 _ULCAST_(1 << 0)
#define CSR_DMW1_MAT _ULCAST_(1 << 4)
#define CSR_DMW1_VSEG _ULCAST_(0xa)
#define CSR_DMW1_BASE (CSR_DMW1_VSEG << DMW_PABITS)
#define CSR_DMW1_INIT (CSR_DMW1_BASE | CSR_DMW1_MAT | CSR_DMW1_PLV0)
#endif
a的出处找到了，32位上，0xa0000000开始的virt是可以被cache的，物理地址就是去掉前面的a。
0x80000000开始的virt addr是不走cache的，转换成物理地址就是把前面的8去掉。
virt转phys就比较简单了，直接取后面的几位。
/*
* Returns the physical address of a KPRANGEx / XKPRANGE address
*/
#define PHYSADDR(a) ((_ACAST32_(a)) & TO_PHYS_MASK)
#ifdef CONFIG_32BIT
#define DMW_PABITS 28
#define TO_PHYS_MASK ((1UL << DMW_PABITS) - 1)
#endif
从注释上看这个机制只是在mem init的时候用，后面怎样还不知道，遇到了再学习。
在soc2上，直接phys=virt， 改了代码后，这部分就跑过去了。
