m68k/atari - stram: alloc ST-RAM pool even if kernel not in ST-RAM
With the kernel loaded to FastRAM (TT-RAM), none of the ST-RAM address range is mapped by init_mem, and ST-RAM is not accessible through the normal allocation pathways as a result. Implement ST-RAM pool allocation to be based on physical addresses always (it already was when the kernel was loaded in ST-RAM). Return kernel virtual addresses as per normal. The current test for the kernel residing in ST-RAM always returns true. Use the bootinfo memory chunk order instead - with the kernel in FastRAM, ST-RAM (phys. 0x0) is not the first chunk. In case the kernel is running from FastRAM, delay mapping of ST-RAM pool until after mem_init. Provide helper functions for those users of ST-RAM that need to be aware of the backing physical addresses. Kudos to Geert for his hints on getting this started. Signed-off-by: Michael Schmitz <schmitz@debian.org> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
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@ -47,6 +47,7 @@ static struct resource stram_pool = {
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static unsigned long pool_size = 1024*1024;
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static unsigned long stram_virt_offset;
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static int __init atari_stram_setup(char *arg)
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{
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@ -67,14 +68,12 @@ early_param("stram_pool", atari_stram_setup);
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void __init atari_stram_init(void)
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{
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int i;
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void *stram_start;
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/*
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* determine whether kernel code resides in ST-RAM
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* (then ST-RAM is the first memory block at virtual 0x0)
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*/
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stram_start = phys_to_virt(0);
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kernel_in_stram = (stram_start == 0);
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kernel_in_stram = (m68k_memory[0].addr == 0);
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for (i = 0; i < m68k_num_memory; ++i) {
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if (m68k_memory[i].addr == 0) {
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@ -89,26 +88,64 @@ void __init atari_stram_init(void)
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/*
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* This function is called from setup_arch() to reserve the pages needed for
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* ST-RAM management.
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* ST-RAM management, if the kernel resides in ST-RAM.
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*/
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void __init atari_stram_reserve_pages(void *start_mem)
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{
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/*
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* always reserve first page of ST-RAM, the first 2 KiB are
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* supervisor-only!
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*/
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if (!kernel_in_stram)
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reserve_bootmem(0, PAGE_SIZE, BOOTMEM_DEFAULT);
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if (kernel_in_stram) {
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pr_debug("atari_stram pool: kernel in ST-RAM, using alloc_bootmem!\n");
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stram_pool.start = (resource_size_t)alloc_bootmem_low_pages(pool_size);
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stram_pool.end = stram_pool.start + pool_size - 1;
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request_resource(&iomem_resource, &stram_pool);
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stram_virt_offset = 0;
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pr_debug("atari_stram pool: size = %lu bytes, resource = %pR\n",
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pool_size, &stram_pool);
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pr_debug("atari_stram pool: stram_virt_offset = %lx\n",
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stram_virt_offset);
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}
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}
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/*
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* This function is called as arch initcall to reserve the pages needed for
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* ST-RAM management, if the kernel does not reside in ST-RAM.
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*/
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int __init atari_stram_map_pages(void)
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{
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if (!kernel_in_stram) {
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/*
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* Skip page 0, as the fhe first 2 KiB are supervisor-only!
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*/
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pr_debug("atari_stram pool: kernel not in ST-RAM, using ioremap!\n");
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stram_pool.start = PAGE_SIZE;
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stram_pool.end = stram_pool.start + pool_size - 1;
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request_resource(&iomem_resource, &stram_pool);
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stram_virt_offset = (unsigned long) ioremap(stram_pool.start,
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resource_size(&stram_pool)) - stram_pool.start;
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pr_debug("atari_stram pool: size = %lu bytes, resource = %pR\n",
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pool_size, &stram_pool);
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pr_debug("atari_stram pool: stram_virt_offset = %lx\n",
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stram_virt_offset);
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}
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return 0;
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}
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arch_initcall(atari_stram_map_pages);
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void *atari_stram_to_virt(unsigned long phys)
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{
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return (void *)(phys + stram_virt_offset);
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}
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EXPORT_SYMBOL(atari_stram_to_virt);
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unsigned long atari_stram_to_phys(void *virt)
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{
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return (unsigned long)(virt - stram_virt_offset);
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}
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EXPORT_SYMBOL(atari_stram_to_phys);
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void *atari_stram_alloc(unsigned long size, const char *owner)
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{
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struct resource *res;
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@ -134,14 +171,14 @@ void *atari_stram_alloc(unsigned long size, const char *owner)
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}
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pr_debug("atari_stram_alloc: returning %pR\n", res);
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return (void *)res->start;
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return atari_stram_to_virt(res->start);
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}
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EXPORT_SYMBOL(atari_stram_alloc);
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void atari_stram_free(void *addr)
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{
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unsigned long start = (unsigned long)addr;
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unsigned long start = atari_stram_to_phys(addr);
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struct resource *res;
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unsigned long size;
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@ -8,6 +8,8 @@
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/* public interface */
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void *atari_stram_alloc(unsigned long size, const char *owner);
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void atari_stram_free(void *);
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void *atari_stram_to_virt(unsigned long phys);
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unsigned long atari_stram_to_phys(void *);
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/* functions called internally by other parts of the kernel */
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void atari_stram_init(void);
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