[U-Boot] [PATCH v2 11/12] arm: add MMU/d-cache support for Faraday cores

Kuo-Jung Su dantesu at gmail.com
Mon Apr 22 03:27:04 CEST 2013


2013/4/19 Albert ARIBAUD <albert.u.boot at aribaud.net>:
> Hi Kuo-Jung,
>
> On Thu, 18 Apr 2013 17:25:38 +0800, Kuo-Jung Su <dantesu at gmail.com>
> wrote:
>
>> From: Kuo-Jung Su <dantesu at faraday-tech.com>
>>
>> This patch would enable MMU for Faraday ARMv5TE cores.
>>
>> Here is the abstract of this MMU design.
>>
>> Assume SDRAM memory region starts at 0x10000000, and its size = 0x800000.
>>
>> 0x00000000 +-------------------+
>>            |                   |
>>            |     UN-CACHED     |
>>            |                   |
>>            |                   |
>> 0x10000000 +-------------------+
>>            |  CACHED (SDRAM)   | <- It's where data/bss/stack lived.
>>            |                   |
>>            |                   |
>> 0x10800000 +-------------------+
>>            |                   |
>>            |                   |
>>            |     UN-CACHED     |
>>            |                   |
>>            |                   |
>> 0xFF800000 +-------------------+
>>            | UN-CACHED (SDRAM) | <- An un-cached shadow of the SDRAM.
>>            |                   |    dma_alloc_coherent() always returns
>>            |                   |    an address in this region.
>> 0xFFFFFFFF +-------------------+
>
> The ASCII map is great for explaining, but I find it a bit big for a
> commit message. Can you summarize it as lines like
>
> 0x00000000-0x0FFFFFFF  not cached
> 0x10000000-0x107FFFFF  cached (SDRAM)
> ...
>
> ?
>

Sure,
it would be updated in that way at next patch.

>> Signed-off-by: Kuo-Jung Su <dantesu at faraday-tech.com>
>> CC: Albert Aribaud <albert.u.boot at aribaud.net>
>> ---
>>  arch/arm/include/asm/dma-mapping.h |   56 ++++++++++++++++++++++--
>>  arch/arm/include/asm/global_data.h |    4 ++
>>  arch/arm/include/asm/io.h          |   84 +++++++++++++++++++++++++++++++++++-
>>  arch/arm/lib/cache-cp15.c          |   42 ++++++++++++++++++
>>  common/cmd_boot.c                  |    4 ++
>>  5 files changed, 186 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
>> index 5bbb0a0..53c4edf 100644
>> --- a/arch/arm/include/asm/dma-mapping.h
>> +++ b/arch/arm/include/asm/dma-mapping.h
>> @@ -3,6 +3,9 @@
>>   * Stelian Pop <stelian at popies.net>
>>   * Lead Tech Design <www.leadtechdesign.com>
>>   *
>> + * (C) Copyright 2010
>> + * Dante Su <dantesu at faraday-tech.com>
>> + *
>>   * See file CREDITS for list of people who contributed to this
>>   * project.
>>   *
>> @@ -24,22 +27,69 @@
>>  #ifndef __ASM_ARM_DMA_MAPPING_H
>>  #define __ASM_ARM_DMA_MAPPING_H
>>
>> +#include <asm/u-boot.h>
>> +#include <asm/global_data.h>
>> +#include <asm/io.h>
>> +#include <malloc.h>
>> +
>>  enum dma_data_direction {
>>       DMA_BIDIRECTIONAL       = 0,
>>       DMA_TO_DEVICE           = 1,
>>       DMA_FROM_DEVICE         = 2,
>>  };
>>
>> -static void *dma_alloc_coherent(size_t len, unsigned long *handle)
>> +static inline void *dma_alloc_coherent(size_t len, unsigned long *handle)
>> +{
>> +#if defined(CONFIG_FARADAY) && !defined(CONFIG_SYS_DCACHE_OFF)
>> +     DECLARE_GLOBAL_DATA_PTR;
>
> I'd rather have the global data ptr be declared outside any function,
> and only once.
>

Got it, thanks

>> +#endif
>> +     void *va = memalign(ARCH_DMA_MINALIGN, len);
>> +
>> +     if (va && handle)
>> +             *handle = virt_to_phys(va);
>> +
>> +#if defined(CONFIG_FARADAY) && !defined(CONFIG_SYS_DCACHE_OFF)
>> +     if (gd->arch.cpu_mmu) {
>> +             /* invalidate the buffer, convert to un-cached address */
>> +             if (va != NULL) {
>> +                     invalidate_dcache_range((ulong)va, (ulong)va + len);
>> +                     va = virt_to_uncached(va);
>> +             }
>> +     }
>> +#endif
>> +
>> +     return va;
>> +}
>> +
>> +static inline void dma_free_coherent(void *va)
>>  {
>> -     *handle = (unsigned long)malloc(len);
>> -     return (void *)*handle;
>> +     free(virt_to_cached(va));
>>  }
>
> If I read this correctly, this code changes the semantics of
> dma_alloc_coherent() for boards other than Faraday-based: before,
> mempry was simply malloc()ed, now it would be memalign()ed then
> virt_to_phys()ed. Why not simply keep the previous implementation under
> a #else...#endif block?
>

Sorry, it's an accident, I'll have it fixed at next version.

>>  static inline unsigned long dma_map_single(volatile void *vaddr, size_t len,
>>                                          enum dma_data_direction dir)
>>  {
>> +#if defined(CONFIG_FARADAY) && !defined(CONFIG_SYS_DCACHE_OFF)
>> +     DECLARE_GLOBAL_DATA_PTR;
>> +
>> +     if (gd->arch.cpu_mmu) {
>> +             switch (dir) {
>> +             case DMA_BIDIRECTIONAL:
>> +             case DMA_TO_DEVICE:
>> +                     flush_dcache_range((ulong)vaddr,
>> +                             (ulong)vaddr + len);
>> +                     break;
>> +
>> +             case DMA_FROM_DEVICE:
>> +                     invalidate_dcache_range((ulong)vaddr,
>> +                             (ulong)vaddr + len);
>> +                     break;
>> +             }
>> +     }
>> +     return virt_to_phys((void *)vaddr);
>> +#else
>>       return (unsigned long)vaddr;
>> +#endif
>>  }
>
> Here we have such a #else/#endif, which makes sure non-Farady boards
> are unaffected.
>
>>  static inline void dma_unmap_single(volatile void *vaddr, size_t len,
>> diff --git a/arch/arm/include/asm/global_data.h b/arch/arm/include/asm/global_data.h
>> index 37ac0da..bd18ff7 100644
>> --- a/arch/arm/include/asm/global_data.h
>> +++ b/arch/arm/include/asm/global_data.h
>> @@ -38,6 +38,10 @@ struct arch_global_data {
>>       unsigned long   pllb_rate_hz;
>>       unsigned long   at91_pllb_usb_init;
>>  #endif
>> +#ifdef CONFIG_FARADAY
>> +     unsigned long   cpu_id;
>> +     unsigned long   cpu_mmu;        /* has mmu */
>> +#endif
>>       /* "static data" needed by most of timer.c on ARM platforms */
>>       unsigned long timer_rate_hz;
>>       unsigned long tbu;
>> diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
>> index 1fbc531..17d8898 100644
>> --- a/arch/arm/include/asm/io.h
>> +++ b/arch/arm/include/asm/io.h
>> @@ -2,6 +2,7 @@
>>   *  linux/include/asm-arm/io.h
>>   *
>>   *  Copyright (C) 1996-2000 Russell King
>> + *  Copyright (C) 2009-2010 Dante Su <dantesu at faraday-tech.com>
>>   *
>>   * This program is free software; you can redistribute it and/or modify
>>   * it under the terms of the GNU General Public License version 2 as
>> @@ -23,6 +24,8 @@
>>  #ifdef __KERNEL__
>>
>>  #include <linux/types.h>
>> +#include <asm/u-boot.h>
>> +#include <asm/global_data.h>
>>  #include <asm/byteorder.h>
>>  #include <asm/memory.h>
>>  #if 0        /* XXX###XXX */
>> @@ -57,9 +60,88 @@ static inline void unmap_physmem(void *vaddr, unsigned long flags)
>>
>>  }
>>
>> +#ifdef CONFIG_FARADAY
>> +
>> +# ifndef CONFIG_SYS_DCACHE_OFF
>> +
>> +static inline ulong uncached_base(volatile gd_t *gd)
>> +{
>> +     return (4096 - (gd->ram_size >> 20)) << 20;
>
> Symbolic constants or a comment would not hurt here.
>

Got it, thanks

>> +}
>> +# endif
>> +
>> +static inline void *virt_to_cached(void *va)
>> +{
>> +# ifndef CONFIG_SYS_DCACHE_OFF
>> +     DECLARE_GLOBAL_DATA_PTR;
>> +     ulong base = uncached_base(gd);
>> +
>> +     if (!gd->arch.cpu_mmu)
>> +             return va;
>> +
>> +     if ((ulong)va >= base &&
>> +             (ulong)va < (base + gd->ram_size))
>> +             va = (void *)((ulong)va - base + CONFIG_SYS_SDRAM_BASE);
>> +# endif      /* !CONFIG_SYS_DCACHE_OFF */
>> +
>> +     return va;
>> +}
>> +
>> +static inline void *virt_to_uncached(void *va)
>> +{
>> +# ifndef CONFIG_SYS_DCACHE_OFF
>> +     DECLARE_GLOBAL_DATA_PTR;
>> +     ulong base = uncached_base(gd);
>> +
>> +     if (!gd->arch.cpu_mmu)
>> +             return va;
>> +
>> +#  ifdef CONFIG_USE_IRQ
>> +     if ((ulong)va < SZ_1M)
>> +             return (void *)(base + (ulong)va);
>> +#  endif
>> +
>> +     if ((ulong)va >= CONFIG_SYS_SDRAM_BASE &&
>> +             (ulong)va < (CONFIG_SYS_SDRAM_BASE + gd->ram_size))
>> +             va = (void *)(base + ((ulong)va - CONFIG_SYS_SDRAM_BASE));
>> +# endif      /* !CONFIG_SYS_DCACHE_OFF */
>> +
>> +     return va;
>> +}
>> +
>> +#endif       /* CONFIG_FARADAY */
>> +
>>  static inline phys_addr_t virt_to_phys(void * vaddr)
>>  {
>> -     return (phys_addr_t)(vaddr);
>> +#if defined(CONFIG_FARADAY) && !defined(CONFIG_SYS_DCACHE_OFF)
>> +
>> +     DECLARE_GLOBAL_DATA_PTR;
>> +     bd_t *bd = gd->bd;
>> +     ulong base = uncached_base(gd);
>> +     ulong phys = (ulong)vaddr;
>> +
>> +     if (!gd->arch.cpu_mmu)
>> +             return (phys_addr_t)phys;
>> +
>> +     if (phys >= base) {
>> +             ulong bank;
>> +             ulong off = phys - base;
>> +             for (bank = 0; bank < CONFIG_NR_DRAM_BANKS; ++bank) {
>> +                     if (bd->bi_dram[bank].size > off)
>> +                             break;
>> +                     off -= bd->bi_dram[bank].size;
>> +             }
>> +             phys = bd->bi_dram[bank].start + off;
>> +     }
>> +# ifdef CONFIG_USE_IRQ
>> +     else if (phys < SZ_1M && bd->bi_dram[0].start != 0)
>> +             phys = bd->bi_dram[0].start + phys;
>> +# endif
>> +
>> +     return (phys_addr_t)phys;
>> +#else
>> +     return (phys_addr_t)vaddr;
>> +#endif
>>  }
>>
>>  /*
>> diff --git a/arch/arm/lib/cache-cp15.c b/arch/arm/lib/cache-cp15.c
>> index 4abe1cf..eee8585 100644
>> --- a/arch/arm/lib/cache-cp15.c
>> +++ b/arch/arm/lib/cache-cp15.c
>> @@ -1,6 +1,8 @@
>>  /*
>>   * (C) Copyright 2002
>>   * Wolfgang Denk, DENX Software Engineering, wd at denx.de.
>> + * (C) Copyright 2010
>> + * Dante Su <dantesu at faraday-tech.com>
>>   *
>>   * See file CREDITS for list of people who contributed to this
>>   * project.
>> @@ -87,6 +89,10 @@ __weak void dram_bank_mmu_setup(int bank)
>>  {
>>       bd_t *bd = gd->bd;
>>       int     i;
>> +#ifdef CONFIG_FARADAY
>> +     ulong ubase, off;
>> +     u32 *page_table = (u32 *)gd->arch.tlb_addr;
>> +#endif
>>
>>       debug("%s: bank: %d\n", __func__, bank);
>>       for (i = bd->bi_dram[bank].start >> 20;
>> @@ -98,6 +104,32 @@ __weak void dram_bank_mmu_setup(int bank)
>>               set_section_dcache(i, DCACHE_WRITEBACK);
>>  #endif
>>       }
>> +#ifdef CONFIG_FARADAY
>> +# ifdef CONFIG_USE_IRQ
>> +     /* map the exception table to 0x00000000 if necessary */
>> +     if (bank == 0 && bd->bi_dram[bank].start != 0) {
>> +             u32 pa = bd->bi_dram[bank].start;
>> +#if defined(CONFIG_SYS_ARM_CACHE_WRITETHROUGH)
>> +             page_table[0] = pa | (3 << 10) | DCACHE_WRITETHROUGH;
>> +#else
>> +             page_table[0] = pa | (3 << 10) | DCACHE_WRITEBACK;
>> +#endif
>> +     }
>> +# endif
>> +     /* calculate address offset */
>> +     off  = 0;
>> +     for (i = 0; i < bank; ++i)
>> +             off += bd->bi_dram[bank].size;
>> +
>> +     /* create memory map */
>> +     ubase = (4096 - (gd->ram_size >> 20)) << 20;
>> +     for (i = 0; i < bd->bi_dram[bank].size >> 20; ++i) {
>> +             u32 pa = bd->bi_dram[bank].start + (i << 20);
>> +             /* create un-cached address map */
>> +             u32 va = ubase + off + (i << 20);
>> +             page_table[va >> 20] = pa | (3 << 10) | DCACHE_OFF;
>> +     }
>> +#endif
>>  }
>>
>>  /* to activate the MMU we need to set up virtual memory: use 1M areas */
>> @@ -126,6 +158,10 @@ static inline void mmu_setup(void)
>>
>>       /* and enable the mmu */
>>       reg = get_cr(); /* get control reg. */
>> +#ifdef CONFIG_FARADAY
>> +     reg |= CR_W;    /* enable write buffer */
>> +     reg |= CR_Z;    /* enable branch prediction */
>> +#endif
>>       cp_delay();
>>       set_cr(reg | CR_M);
>>  }
>> @@ -140,9 +176,15 @@ static void cache_enable(uint32_t cache_bit)
>>  {
>>       uint32_t reg;
>>
>> +#ifdef CONFIG_FARADAY
>> +     if (!gd->arch.cpu_mmu && (cache_bit == CR_C))
>> +             return;
>> +#endif
>> +
>>       /* The data cache is not active unless the mmu is enabled too */
>>       if ((cache_bit == CR_C) && !mmu_enabled())
>>               mmu_setup();
>> +
>>       reg = get_cr(); /* get control reg. */
>>       cp_delay();
>>       set_cr(reg | cache_bit);
>> diff --git a/common/cmd_boot.c b/common/cmd_boot.c
>> index d3836fd..b2477e8 100644
>> --- a/common/cmd_boot.c
>> +++ b/common/cmd_boot.c
>> @@ -50,6 +50,10 @@ static int do_go(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
>>
>>       printf ("## Starting application at 0x%08lX ...\n", addr);
>>
>> +#if defined(__ARM__) && !defined(CONFIG_SYS_DCACHE_OFF)
>> +     cleanup_before_linux();
>> +#endif
>> +
>>       /*
>>        * pass address parameter as argv[0] (aka command name),
>>        * and all remaining args
>> --
>> 1.7.9.5
>>
>
>
> Amicalement,
> --
> Albert.



--
Best wishes,
Kuo-Jung Su


More information about the U-Boot mailing list