[PATCH 4/6] libmm-libbsp-arm-shared. libmm low-level implementation that can be shared between many ARM targets. mminit.c contains initialization function for arm-cp15 and setup page tables. After that it enables MMU and Cache unit part of BSP initialization process. mm.c translates attributes from high-level to CPU specific attributes and apply them dynamically.

Hesham Moustafa heshamelmatary at gmail.com
Thu Sep 12 18:26:00 UTC 2013 

On Thu, Sep 12, 2013 at 8:17 PM, Gedare Bloom <gedare at rtems.org> wrote:

> On Thu, Sep 12, 2013 at 2:10 PM, Hesham Moustafa
> <heshamelmatary at gmail.com> wrote:
> >
> >
> >
> > On Thu, Sep 12, 2013 at 3:01 PM, Gedare Bloom <gedare at rtems.org> wrote:
> >>
> >> On Thu, Sep 12, 2013 at 2:59 AM, Hesham AL-Matary
> >> <heshamelmatary at gmail.com> wrote:
> >> > ---
> >> >  .../lib/libbsp/arm/shared/include/arm-cp15-start.h | 11 ++++--
> >> >  c/src/lib/libbsp/arm/shared/mm.c                   | 46
> >> > ++++++++++++++++++++++
> >> >  c/src/lib/libbsp/arm/shared/mminit.c               | 27 +++++++++++++
> >> >  3 files changed, 80 insertions(+), 4 deletions(-)
> >> >  create mode 100644 c/src/lib/libbsp/arm/shared/mm.c
> >> >  create mode 100644 c/src/lib/libbsp/arm/shared/mminit.c
> >> >
> >> > diff --git a/c/src/lib/libbsp/arm/shared/include/arm-cp15-start.h
> >> > b/c/src/lib/libbsp/arm/shared/include/arm-cp15-start.h
> >> > index 01f3104..b463b1f 100644
> >> > --- a/c/src/lib/libbsp/arm/shared/include/arm-cp15-start.h
> >> > +++ b/c/src/lib/libbsp/arm/shared/include/arm-cp15-start.h
> >> > @@ -1,4 +1,5 @@
> >> > -/*
> >> > +/*
> >> > + * Copyright (c) 2013 Hesham AL-Matary.
> >> >   * Copyright (c) 2009-2013 embedded brains GmbH.  All rights
> reserved.
> >> >   *
> >> >   *  embedded brains GmbH
> >> > @@ -89,7 +90,7 @@
> >> > arm_cp15_start_setup_translation_table_and_enable_mmu_and_cache(
> >> >
> >> >    /* Initialize translation table with invalid entries */
> >> Fix this comment (assuming the change below now populates the ttb with
> >> valid entries).
> >>
> >> >    for (i = 0; i < ARM_MMU_TRANSLATION_TABLE_ENTRY_COUNT; ++i) {
> >> > -    ttb [i] = 0;
> >> > +    ttb [i] = (i << ARM_MMU_SECT_BASE_SHIFT) |
> >> > ARMV7_MMU_DATA_READ_WRITE;
> >> >    }
> >> >
> >> >    for (i = 0; i < config_count; ++i) {
> >> > @@ -97,11 +98,13 @@
> >> > arm_cp15_start_setup_translation_table_and_enable_mmu_and_cache(
> >> >    }
> >> >
> >> >    /* Enable MMU and cache */
> >> > -  ctrl |= ARM_CP15_CTRL_I | ARM_CP15_CTRL_C | ARM_CP15_CTRL_M;
> >> > +  ctrl |= ARM_CP15_CTRL_AFE | ARM_CP15_CTRL_S | ARM_CP15_CTRL_I |
> >> > +          ARM_CP15_CTRL_C | ARM_CP15_CTRL_M  | ARM_CP15_CTRL_XP;
> >> > +
> >> >    arm_cp15_set_control(ctrl);
> >> >  }
> >> >
> >> > -BSP_START_TEXT_SECTION static inline uint32_t
> >> > +BSP_START_TEXT_SECTION inline uint32_t
> >> undo this change.
> >
> > I already did, but that caused undefined reference to
> > arm_cp15_start_setup_mmu_and_cache
> > compilation error at arm-a9mpcore-start.h:89 when I was compiling
> realview
> > with --enable-smp
> > option.
> You should figure out why that happened. Changing this function to
> non-inline does not seem like the right answer.
>
 The change is that it's not static anymore because it's called from
another file too.

> >
> >>
> >> >  arm_cp15_start_setup_mmu_and_cache(uint32_t ctrl_clear, uint32_t
> >> > ctrl_set)
> >> >  {
> >> >    uint32_t ctrl = arm_cp15_get_control();
> >> > diff --git a/c/src/lib/libbsp/arm/shared/mm.c
> >> > b/c/src/lib/libbsp/arm/shared/mm.c
> >> > new file mode 100644
> >> > index 0000000..36e90be
> >> > --- /dev/null
> >> > +++ b/c/src/lib/libbsp/arm/shared/mm.c
> >> > @@ -0,0 +1,46 @@
> >> > +/*
> >> > + * Copyright (c) 2013 Hesham AL-Matary.
> >> > + *
> >> > + * The license and distribution terms for this file may be
> >> > + * found in the file LICENSE in this distribution or at
> >> > + * http://www.rtems.com/license/LICENSE.
> >> > + */
> >> > +
> >> > +#include <bsp/mm.h>
> >> > +#include <libcpu/arm-cp15.h>
> >> > +#include <rtems/score/mm.h>
> >> > +
> >> > +#define LIBMM_REGION_IS_CACHE_ENABLED(attr) \
> >> > +  (((attr) >> RTEMS_MM_REGION_BIT_CACHE) & 1U)
> >> > +#define LIBMM_REGION_IS_PROTECTION_WRITE_ENABLED(attr) \
> >> > +  (((attr) >> RTEMS_MM_REGION_BIT_WRITE) & 1U)
> >> > +#define LIBMM_REGION_IS_DEVICE_TYPE(attr) \
> >> > +  (((attr) >> RTEMS_MM_REGION_BIT_DEVICE) & 1U)
> >> > +#define LIBMM_REGION_IS_SHARED_MEMORY(attr) \
> >> > +  (((attr) >> RTEMS_MM_REGION_BIT_SHARED) & 1U)
> >> > +
> >> Should these macros be provided by the score/mm.h?
> >>
> > mm.h or mmimpl.h whatever. It's used by applications calls as well as
> > mm.c which used these definitions to translate attributes to CPU specific
> > ones.
> mm.h so that the macros are "visible".
>
> Yes for both application and low-level implementation code.

> >>
> >> > +#define ARM_MMU_BIND_SECTION_TO_CLIENT_DOMAIN \
> >> > +  (ARM_MMU_DEFAULT_CLIENT_DOMAIN << ARM_MMU_SECT_DOMAIN_SHIFT)
> >> > +
> >> > +#define LIBMM_TRANSLATE_ATTRIBUTES_TO_CPU(attr) \
> >> > +  ((ARM_MMU_BIND_SECTION_TO_CLIENT_DOMAIN) \
> >> > +  | (ARM_MMU_SECT_AP_0) \
> >> > +  | (LIBMM_REGION_IS_PROTECTION_WRITE_ENABLED(attr) ? \
> >> > +  0U : (ARM_MMU_SECT_AP_2)) \
> >> > +  | (LIBMM_REGION_IS_CACHE_ENABLED(attr) ? \
> >> > +  (ARM_MMU_SECT_TEX_0|ARM_MMU_SECT_C|ARM_MMU_SECT_B) : 0U) \
> >> > +  | (LIBMM_REGION_IS_DEVICE_TYPE(attr) ? ARM_MMU_SECT_B : 0U) \
> >> > +  | (LIBMM_REGION_IS_SHARED_MEMORY(attr) ? ARM_MMU_SECT_S : 0U) \
> >> > +  | (ARM_MMU_SECT_DEFAULT))
> >> > +
> >> This macro could properly be named something simpler since it is local
> >> to this .c file.
> >>
> > Sure, I just wanted to give it a self-describing name.
> >>
> >> > +void bsp_memory_management_set_attributes(
> >> > +  uintptr_t base,
> >> > +  size_t size,
> >> > +  uint32_t attr
> >> > +)
> >> > +{
> >> > +  uintptr_t end = (uint32_t)base + (uint32_t)size;
> >> Don't cast base and size here.
> >>
> >> > +  uint32_t section_flags = LIBMM_TRANSLATE_ATTRIBUTES_TO_CPU(attr);
> >> > +
> >> > +  arm_cp15_set_translation_table_entries(base, end, section_flags);
> >> > +}
> >> > diff --git a/c/src/lib/libbsp/arm/shared/mminit.c
> >> > b/c/src/lib/libbsp/arm/shared/mminit.c
> >> > new file mode 100644
> >> > index 0000000..333d65c
> >> > --- /dev/null
> >> > +++ b/c/src/lib/libbsp/arm/shared/mminit.c
> >> > @@ -0,0 +1,27 @@
> >> > +/*
> >> > + * Copyright (c) 2013 Hesham AL-Matary.
> >> > + *
> >> > + * The license and distribution terms for this file may be
> >> > + * found in the file LICENSE in this distribution or at
> >> > + * http://www.rtems.com/license/LICENSE.
> >> > + */
> >> > +#include <bsp/arm-cp15-start.h>
> >> > +#include <bsp/linker-symbols.h>
> >> > +#include <bsp/mm.h>
> >> > +#include <bsp/start.h>
> >> > +
> >> > +extern const mm_init_start_config bsp_mm_config_table[];
> >> > +extern const size_t bsp_mm_config_table_size;
> >> > +
> >> > +BSP_START_TEXT_SECTION void bsp_memory_management_initialize(void)
> >> > +{
> >> > +  uint32_t ctrl = arm_cp15_get_control();
> >> > +
> >> > +  arm_cp15_start_setup_translation_table_and_enable_mmu_and_cache(
> >> > +  ctrl,
> >> > +  (uint32_t *) bsp_translation_table_base,
> >> > +  ARM_MMU_DEFAULT_CLIENT_DOMAIN,
> >> > +  &bsp_mm_config_table[0],
> >> > +  bsp_mm_config_table_size
> >> > +  );
> >> Fix indentation level of nested lines of arguments. Also, this
> >> mminit.c file does not make sense until you add at least one of the
> >> ARM bsps using it.
> >>
> > realview, xilinx, and raspberry currently
> > calls the initialization function within this
> > mminit.c
> Right, except they have not been added prior to this patch. Without
> knowledge about them, this code does not make sense, right? Anyway, I
> think it might be useful to re-arrange the order of these patches in
> order to add the raspberrypi mmu handling first, and then show how to
> consolidate the ARM MMU handling, and then offer some generic routines
> in the bsp layer (e.g. bsp_memory_management_initialize) that can
> unify the other BSPs like powerpc ones that will also have MMU/MPU
> requirements.
>
> Sure, that means that the next set of patches should only include
raspberrypi
implementation only, Right ?

> >>
> >> > +}
> >> > --
> >> > 1.8.3.1
> >> >
> >> > _______________________________________________
> >> > rtems-devel mailing list
> >> > rtems-devel at rtems.org
> >> > http://www.rtems.org/mailman/listinfo/rtems-devel
> >
> >
>
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