From f88747e7f68866f2f82cef1363c5b8e7aa13b0a3 Mon Sep 17 00:00:00 2001 From: Trent Piepho Date: Mon, 8 Dec 2008 19:34:57 -0800 Subject: powerpc/fsl-booke: Remove code duplication in lowmem mapping The code to map lowmem uses three CAM aka TLB[1] entries to cover it. The size of each is stored in three globals named __cam0, __cam1, and __cam2. All the code that uses them is duplicated three times for each of the three variables. We have these things called arrays and loops.... Once converted to use an array, it will be easier to make the number of CAMs configurable. Signed-off-by: Trent Piepho Signed-off-by: Kumar Gala --- arch/powerpc/mm/fsl_booke_mmu.c | 79 ++++++++++++++++------------------------- 1 file changed, 31 insertions(+), 48 deletions(-) (limited to 'arch/powerpc/mm') diff --git a/arch/powerpc/mm/fsl_booke_mmu.c b/arch/powerpc/mm/fsl_booke_mmu.c index 1971e4ee3d6..1dabe1a1751 100644 --- a/arch/powerpc/mm/fsl_booke_mmu.c +++ b/arch/powerpc/mm/fsl_booke_mmu.c @@ -56,7 +56,7 @@ extern void loadcam_entry(unsigned int index); unsigned int tlbcam_index; -static unsigned long __cam0, __cam1, __cam2; +static unsigned long cam[3]; #define NUM_TLBCAMS (16) @@ -152,19 +152,19 @@ void invalidate_tlbcam_entry(int index) loadcam_entry(index); } -void __init cam_mapin_ram(unsigned long cam0, unsigned long cam1, - unsigned long cam2) +unsigned long __init mmu_mapin_ram(void) { - settlbcam(0, PAGE_OFFSET, memstart_addr, cam0, _PAGE_KERNEL, 0); - tlbcam_index++; - if (cam1) { - tlbcam_index++; - settlbcam(1, PAGE_OFFSET+cam0, memstart_addr+cam0, cam1, _PAGE_KERNEL, 0); - } - if (cam2) { + unsigned long virt = PAGE_OFFSET; + phys_addr_t phys = memstart_addr; + + while (cam[tlbcam_index] && tlbcam_index < ARRAY_SIZE(cam)) { + settlbcam(tlbcam_index, virt, phys, cam[tlbcam_index], _PAGE_KERNEL, 0); + virt += cam[tlbcam_index]; + phys += cam[tlbcam_index]; tlbcam_index++; - settlbcam(2, PAGE_OFFSET+cam0+cam1, memstart_addr+cam0+cam1, cam2, _PAGE_KERNEL, 0); } + + return virt - PAGE_OFFSET; } /* @@ -175,51 +175,34 @@ void __init MMU_init_hw(void) flush_instruction_cache(); } -unsigned long __init mmu_mapin_ram(void) -{ - cam_mapin_ram(__cam0, __cam1, __cam2); - - return __cam0 + __cam1 + __cam2; -} - - void __init adjust_total_lowmem(void) { - phys_addr_t max_lowmem_size = __max_low_memory; - phys_addr_t cam_max_size = 0x10000000; phys_addr_t ram; + unsigned int max_cam = 28; /* 2^28 = 256 Mb */ + char buf[ARRAY_SIZE(cam) * 5 + 1], *p = buf; + int i; - /* adjust CAM size to max_lowmem_size */ - if (max_lowmem_size < cam_max_size) - cam_max_size = max_lowmem_size; - - /* adjust lowmem size to max_lowmem_size */ - ram = min(max_lowmem_size, total_lowmem); + /* adjust lowmem size to __max_low_memory */ + ram = min((phys_addr_t)__max_low_memory, (phys_addr_t)total_lowmem); /* Calculate CAM values */ - __cam0 = 1UL << 2 * (__ilog2(ram) / 2); - if (__cam0 > cam_max_size) - __cam0 = cam_max_size; - ram -= __cam0; - if (ram) { - __cam1 = 1UL << 2 * (__ilog2(ram) / 2); - if (__cam1 > cam_max_size) - __cam1 = cam_max_size; - ram -= __cam1; - } - if (ram) { - __cam2 = 1UL << 2 * (__ilog2(ram) / 2); - if (__cam2 > cam_max_size) - __cam2 = cam_max_size; - ram -= __cam2; + __max_low_memory = 0; + for (i = 0; ram && i < ARRAY_SIZE(cam); i++) { + unsigned int camsize = __ilog2(ram) & ~1U; + if (camsize > max_cam) + camsize = max_cam; + cam[i] = 1UL << camsize; + ram -= cam[i]; + __max_low_memory += cam[i]; + + p += sprintf(p, "%lu/", cam[i] >> 20); } + for (; i < ARRAY_SIZE(cam); i++) + p += sprintf(p, "0/"); + p[-1] = '\0'; - printk(KERN_INFO "Memory CAM mapping: CAM0=%ldMb, CAM1=%ldMb," - " CAM2=%ldMb residual: %ldMb\n", - __cam0 >> 20, __cam1 >> 20, __cam2 >> 20, - (long int)((total_lowmem - __cam0 - __cam1 - __cam2) - >> 20)); - __max_low_memory = __cam0 + __cam1 + __cam2; + pr_info("Memory CAM mapping: %s Mb, residual: %ldMb\n", buf, + (total_lowmem - __max_low_memory) >> 20); __initial_memory_limit_addr = memstart_addr + __max_low_memory; } -- cgit v1.2.3 From c8f3570b7e2dd070ba6da41f3ed4ffb4e1d296af Mon Sep 17 00:00:00 2001 From: Trent Piepho Date: Mon, 8 Dec 2008 19:34:59 -0800 Subject: powerpc/fsl-booke: Allow larger CAM sizes than 256 MB The code that maps kernel low memory would only use page sizes up to 256 MB. On E500v2 pages up to 4 GB are supported. However, a page must be aligned to a multiple of the page's size. I.e. 256 MB pages must aligned to a 256 MB boundary. This was enforced by a requirement that the physical and virtual addresses of the start of lowmem be aligned to 256 MB. Clearly requiring 1GB or 4GB alignment to allow pages of that size isn't acceptable. To solve this, I simply have adjust_total_lowmem() take alignment into account when it decides what size pages to use. Give it PAGE_OFFSET = 0x7000_0000, PHYSICAL_START = 0x3000_0000, and 2GB of RAM, and it will map pages like this: PA 0x3000_0000 VA 0x7000_0000 Size 256 MB PA 0x4000_0000 VA 0x8000_0000 Size 1 GB PA 0x8000_0000 VA 0xC000_0000 Size 256 MB PA 0x9000_0000 VA 0xD000_0000 Size 256 MB PA 0xA000_0000 VA 0xE000_0000 Size 256 MB Because the lowmem mapping code now takes alignment into account, PHYSICAL_ALIGN can be lowered from 256 MB to 64 MB. Even lower might be possible. The lowmem code will work down to 4 kB but it's possible some of the boot code will fail before then. Poor alignment will force small pages to be used, which combined with the limited number of TLB1 pages available, will result in very little memory getting mapped. So alignments less than 64 MB probably aren't very useful anyway. Signed-off-by: Trent Piepho Signed-off-by: Kumar Gala --- arch/powerpc/mm/fsl_booke_mmu.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/mm') diff --git a/arch/powerpc/mm/fsl_booke_mmu.c b/arch/powerpc/mm/fsl_booke_mmu.c index 1dabe1a1751..dfd292748e6 100644 --- a/arch/powerpc/mm/fsl_booke_mmu.c +++ b/arch/powerpc/mm/fsl_booke_mmu.c @@ -179,9 +179,14 @@ void __init adjust_total_lowmem(void) { phys_addr_t ram; - unsigned int max_cam = 28; /* 2^28 = 256 Mb */ + unsigned int max_cam = (mfspr(SPRN_TLB1CFG) >> 16) & 0xff; char buf[ARRAY_SIZE(cam) * 5 + 1], *p = buf; int i; + unsigned long virt = PAGE_OFFSET & 0xffffffffUL; + unsigned long phys = memstart_addr & 0xffffffffUL; + + /* Convert (4^max) kB to (2^max) bytes */ + max_cam = max_cam * 2 + 10; /* adjust lowmem size to __max_low_memory */ ram = min((phys_addr_t)__max_low_memory, (phys_addr_t)total_lowmem); @@ -190,11 +195,18 @@ adjust_total_lowmem(void) __max_low_memory = 0; for (i = 0; ram && i < ARRAY_SIZE(cam); i++) { unsigned int camsize = __ilog2(ram) & ~1U; + unsigned int align = __ffs(virt | phys) & ~1U; + + if (camsize > align) + camsize = align; if (camsize > max_cam) camsize = max_cam; + cam[i] = 1UL << camsize; ram -= cam[i]; __max_low_memory += cam[i]; + virt += cam[i]; + phys += cam[i]; p += sprintf(p, "%lu/", cam[i] >> 20); } -- cgit v1.2.3 From 96051465fdc29e00dd14b484a45daac089c657f8 Mon Sep 17 00:00:00 2001 From: Trent Piepho Date: Mon, 8 Dec 2008 19:34:58 -0800 Subject: powerpc/fsl-booke: Make CAM entries used for lowmem configurable On booke processors, the code that maps low memory only uses up to three CAM entries, even though there are sixteen and nothing else uses them. Make this number configurable in the advanced options menu along with max low memory size. If one wants 1 GB of lowmem, then it's typically necessary to have four CAM entries. Signed-off-by: Trent Piepho Signed-off-by: Kumar Gala --- arch/powerpc/mm/fsl_booke_mmu.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/mm') diff --git a/arch/powerpc/mm/fsl_booke_mmu.c b/arch/powerpc/mm/fsl_booke_mmu.c index dfd292748e6..0b9ba6be49d 100644 --- a/arch/powerpc/mm/fsl_booke_mmu.c +++ b/arch/powerpc/mm/fsl_booke_mmu.c @@ -56,10 +56,14 @@ extern void loadcam_entry(unsigned int index); unsigned int tlbcam_index; -static unsigned long cam[3]; +static unsigned long cam[CONFIG_LOWMEM_CAM_NUM]; #define NUM_TLBCAMS (16) +#if defined(CONFIG_LOWMEM_CAM_NUM_BOOL) && (CONFIG_LOWMEM_CAM_NUM >= NUM_TLBCAMS) +#error "LOWMEM_CAM_NUM must be less than NUM_TLBCAMS" +#endif + struct tlbcam TLBCAM[NUM_TLBCAMS]; struct tlbcamrange { -- cgit v1.2.3