GSoC 2016: Low Level Peripherals & SD Card Support for Raspberry Pi
Pavel Pisa
ppisa4lists at pikron.com
Wed Apr 27 08:53:09 UTC 2016
Hello everybody
and especially those who want to work on RPi.
Before this sound of GSoC start, we should think
what should be integrated from YANG Qiao patches.
If you expect that mailbox services would be required
to access VideoCore and boot data then I think
that YANG Qiao work is valuable and ready for mainline
https://github.com/yangqiao/rtems/commits/master
Problem is that my final round of remarks regarding
to update of MMU setup to reflect actual RPi version
SDRAM size and not overlap mapping table with VideoCore
data area has not been processed.
I can help in this area but I have only RPi 1 for testing now.
Bets wishes,
Pavel
---------- Forwarded Message ----------
Subject: Re: [PATCH 4/6] add fb support for rpi bsp
Date: Monday 24 of August 2015, 19:50:04
From: Pavel Pisa <pisa at cmp.felk.cvut.cz>
To: devel at rtems.org, YANG QIAO <yangqiao0505 at me.com>, Joel Sherrill
<joel.sherrill at oarcorp.com>, Gedare Bloom <gedare at gwu.edu>
Hello Giao, Joel and Gedare,
there are more technical problems to discuss.
But I start with question if RPi video support
should be unconditional. I am not sure if VideoCore
activation has some consequences to ARM system throughput
but at least it slows down startup.
So there can be resons to disable video initialization.
We have two options now
--video=<W>x<H>
--console=fbdev
If --video is not specified then VideoCore is initialized
and best fitting mode for monitor is selected. That is great,
but I suggest two more valid options for --video option.
The value "off" should disable graphics even if monitor
is connected. The option "auto" should behave as it behaves now.
The default behavior then can be changed to even to not
start video automatically but only when "--video" option is present.
This is behavior of pc386 BSP for now. But default behavior with
graphic enabled if monitor is connected is more appropriate
for RPi. But disable option even in case of problem localization
is important.
The default console output to serial line is right according
to me.
The critical part is memory setup which has still some
problems to solve. Comments inlined.
On Thursday 13 of August 2015 00:08:03 YANG QIAO wrote:
> From: YANG Qiao <yangqiao0505 at me.com>
>
> ---
> c/src/lib/libbsp/arm/raspberrypi/Makefile.am | 5 +-
> c/src/lib/libbsp/arm/raspberrypi/console/fb.c | 331
> +++++++++++++++++++++ c/src/lib/libbsp/arm/raspberrypi/include/bsp.h |
> 2 +
> .../arm/raspberrypi/startup/bspgetworkarea.c | 61 ++++
> c/src/lib/libbsp/arm/raspberrypi/startup/linkcmds | 5 +-
> c/src/lib/libbsp/arm/raspberrypi/startup/mminit.c | 42 +++
> 6 files changed, 442 insertions(+), 4 deletions(-)
> create mode 100644 c/src/lib/libbsp/arm/raspberrypi/console/fb.c
> create mode 100644
> c/src/lib/libbsp/arm/raspberrypi/startup/bspgetworkarea.c create mode
> 100644 c/src/lib/libbsp/arm/raspberrypi/startup/mminit.c
>
> diff --git a/c/src/lib/libbsp/arm/raspberrypi/Makefile.am
> b/c/src/lib/libbsp/arm/raspberrypi/Makefile.am index e0b4806..b4853a6
> 100644
> --- a/c/src/lib/libbsp/arm/raspberrypi/Makefile.am
> +++ b/c/src/lib/libbsp/arm/raspberrypi/Makefile.am
> @@ -79,7 +79,6 @@ libbsp_a_LIBADD =
> # Shared
> libbsp_a_SOURCES += ../../shared/bootcard.c
> libbsp_a_SOURCES += ../../shared/bspclean.c
> -libbsp_a_SOURCES += ../../shared/bspgetworkarea.c
> libbsp_a_SOURCES += ../../shared/bsplibc.c
> libbsp_a_SOURCES += ../../shared/bsppost.c
> libbsp_a_SOURCES += ../../shared/bsppredriverhook.c
> @@ -97,6 +96,7 @@ libbsp_a_SOURCES += ../shared/arm-cp15-set-ttb-entries.c
> libbsp_a_SOURCES += ../../shared/bspreset_loop.c
> libbsp_a_SOURCES += startup/bspstart.c
> libbsp_a_SOURCES += startup/cmdline.c
> +libbsp_a_SOURCES += startup/bspgetworkarea.c
>
> # IRQ
> libbsp_a_SOURCES += ../shared/arm-cp15-set-exception-handler.c
> @@ -115,6 +115,7 @@ libbsp_a_SOURCES += ../../shared/console_select.c
> libbsp_a_SOURCES += ../../shared/console_write.c
> libbsp_a_SOURCES += console/console-config.c
> libbsp_a_SOURCES += console/usart.c
> +libbsp_a_SOURCES += console/fb.c
>
> # clock
> libbsp_a_SOURCES += clock/clockdrv.c ../../../shared/clockdrv_shell.h
> @@ -147,7 +148,7 @@ libbsp_a_SOURCES += startup/bspstarthooks.c
>
> # LIBMM
> libbsp_a_SOURCES += startup/mm_config_table.c
> -libbsp_a_SOURCES += ../shared/mminit.c
> +libbsp_a_SOURCES += startup/mminit.c
>
>
> ###########################################################################
>#### # Network #
> diff --git a/c/src/lib/libbsp/arm/raspberrypi/console/fb.c
> b/c/src/lib/libbsp/arm/raspberrypi/console/fb.c new file mode 100644
> index 0000000..a83d560
> --- /dev/null
> +++ b/c/src/lib/libbsp/arm/raspberrypi/console/fb.c
> @@ -0,0 +1,331 @@
> +/**
> + * @file
> + *
> + * @ingroup raspberrypi
> + *
> + * @brief framebuffer support.
> + */
> +
> +/*
> + * Copyright (c) 2015 Yang Qiao
> + *
> + * The license and distribution terms for this file may be
> + * found in the file LICENSE in this distribution or at
> + *
> + * http://www.rtems.org/license/LICENSE
> + *
> + */
> +
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <errno.h>
> +#include <sys/types.h>
> +
> +#include <bsp.h>
> +#include <bsp/raspberrypi.h>
> +#include <bsp/mailbox.h>
> +#include <bsp/vc.h>
> +
> +#include <rtems.h>
> +#include <rtems/libio.h>
> +#include <rtems/fb.h>
> +#include <rtems/framebuffer.h>
> +#include <rtems/score/atomic.h>
> +
> +#define SCREEN_WIDTH 1024
> +#define SCREEN_HEIGHT 768
> +#define BPP 32
> +#define BUFFER_SIZE (SCREEN_WIDTH*SCREEN_HEIGHT*BPP/8)
> +
> +/* flag to limit driver to protect against multiple opens */
> +static Atomic_Flag driver_mutex;
> +
> +/*
> + * screen information for the driver (fb0).
> + */
> +
> +static struct fb_var_screeninfo fb_var_info = {
> + .xres = SCREEN_WIDTH,
> + .yres = SCREEN_HEIGHT,
> + .bits_per_pixel = BPP
> +};
> +
> +static struct fb_fix_screeninfo fb_fix_info = {
> + .smem_start = (void *) NULL,
> + .smem_len = 0,
> + .type = FB_TYPE_PACKED_PIXELS,
> + .visual = FB_VISUAL_TRUECOLOR,
> + .line_length = 0
> +};
> +
> +int raspberrypi_get_fix_screen_info( struct fb_fix_screeninfo *info )
> +{
> + *info = fb_fix_info;
> + return 0;
> +}
> +
> +int raspberrypi_get_var_screen_info( struct fb_var_screeninfo *info )
> +{
> + *info = fb_var_info;
> + return 0;
> +}
> +
> +static int
> +find_mode_from_cmdline(void)
> +{
> + const char* opt;
> + char* endptr;
> + uint32_t width;
> + uint32_t height;
> + uint32_t bpp;
> + opt = rpi_cmdline_arg("--video=");
> + if (opt)
> + {
> + opt += sizeof("--video=")-1;
> + width = strtol(opt, &endptr, 10);
> + if (*endptr != 'x')
> + {
> + return -2;
> + }
check there for "off" and "auto" and use some
reasonable return values to control whether
automatic mode selection should be run later
or display should be left off
> + opt = endptr+1;
> + height = strtol(opt, &endptr, 10);
> + switch (*endptr)
> + {
> + case '-':
> + opt = endptr+1;
> + if (strlen(opt) <= 2)
> + bpp = strtol(opt, &endptr, 10);
> + else
> + {
> + bpp = strtol(opt, &endptr, 10);
> + if (*endptr != ' ')
> + {
> + return -4;
> + }
> + }
> + case ' ':
> + case 0:
> + break;
> + default:
> + return -3;
> + }
> + }
> + else
> + return -1;
> +
> + fb_var_info.xres = width;
> + fb_var_info.yres = height;
> +
> + return 0;
> +}
> +
> +static int
> +find_mode_from_vc(void)
> +{
> + bcm2835_get_display_size_entries entries;
> + bcm2835_mailbox_get_display_size(&entries);
> + unsigned int width = entries.width;
> + unsigned int height = entries.height;
> +
> + if (width == 0 || height == 0)
> + {
> + fb_var_info.xres = SCREEN_WIDTH;
> + fb_var_info.yres = SCREEN_HEIGHT;
> + }
> + else
> + {
> + fb_var_info.xres = width;
> + fb_var_info.yres = height;
> + }
> +
> + return 0;
> +}
> +
> +static bool
> +hdmi_is_present(void)
> +{
> + bcm2835_get_display_size_entries entries;
> + bcm2835_mailbox_get_display_size(&entries);
> + if(entries.width == 0x290 && entries.height ==0x1A0 )
> + {
> + return false;
> + }
> + else
> + {
> + return true;
> + }
> +}
> +
> +int
> +fb_init(void)
> +{
> + if (fb_fix_info.smem_start != NULL)
> + {
> + return -2;
> + }
> +
> + if (hdmi_is_present() == false)
> + {
> + return -3;
> + }
> +
> + if (find_mode_from_cmdline())
> + {
> + if(find_mode_from_vc())
> + return -1;
> + }
> +
> + bcm2835_init_frame_buffer_entries init_frame_buffer_entries;
> + init_frame_buffer_entries.xres = fb_var_info.xres;
> + init_frame_buffer_entries.yres = fb_var_info.yres;
> + init_frame_buffer_entries.xvirt = fb_var_info.xres;
> + init_frame_buffer_entries.yvirt = fb_var_info.yres;
> + init_frame_buffer_entries.depth = fb_var_info.bits_per_pixel;
> + init_frame_buffer_entries.pixel_order = bcm2835_mailbox_pixel_order_rgb;
> + init_frame_buffer_entries.alpha_mode =
> bcm2835_mailbox_alpha_mode_0_opaque; + init_frame_buffer_entries.voffset_x
> = 0;
> + init_frame_buffer_entries.voffset_y = 0;
> + init_frame_buffer_entries.overscan_left = 0;
> + init_frame_buffer_entries.overscan_right = 0;
> + init_frame_buffer_entries.overscan_top = 0;
> + init_frame_buffer_entries.overscan_bottom = 0;
> + bcm2835_mailbox_init_frame_buffer(&init_frame_buffer_entries);
> +
> + bcm2835_get_pitch_entries get_pitch_entries;
> + bcm2835_mailbox_get_pitch(&get_pitch_entries);
> +
> + fb_var_info.xres = init_frame_buffer_entries.xres;
> + fb_var_info.yres = init_frame_buffer_entries.yres;
> + fb_var_info.bits_per_pixel = init_frame_buffer_entries.depth;
> + fb_fix_info.smem_start = init_frame_buffer_entries.base;
> + fb_fix_info.smem_len = init_frame_buffer_entries.size;
> + fb_fix_info.line_length = get_pitch_entries.pitch;
> +
> + return 0;
> +}
> +
> +
> +/*
> + * fbds device driver initialize entry point.
> + */
> +
> +rtems_device_driver
> +frame_buffer_initialize (rtems_device_major_number major,
> + rtems_device_minor_number minor, void *arg)
> +{
> + rtems_status_code status;
> +
> + /* register the devices */
> + status = rtems_io_register_name (FRAMEBUFFER_DEVICE_0_NAME, major, 0);
> + if (status != RTEMS_SUCCESSFUL) {
> + printk ("[!] error registering framebuffer\n");
> + rtems_fatal_error_occurred (status);
> + }
> + _Atomic_Flag_clear(&driver_mutex, ATOMIC_ORDER_RELEASE);
> + return RTEMS_SUCCESSFUL;
> +}
> +
> +/*
> + * fbds device driver open operation.
> + */
> +
> +rtems_device_driver
> +frame_buffer_open (rtems_device_major_number major,
> + rtems_device_minor_number minor, void *arg)
> +{
> + if (_Atomic_Flag_test_and_set(&driver_mutex, ATOMIC_ORDER_ACQUIRE) != 0
> ) { + printk( "FB_CIRRUS could not lock driver_mutex\n" );
> + return RTEMS_UNSATISFIED;
> + }
> +
> + memset ((void *)fb_fix_info.smem_start, 0, fb_fix_info.smem_len);
> + return RTEMS_SUCCESSFUL;
> +}
> +
> +/*
> + * fbds device driver close operation.
> + */
> +
> +rtems_device_driver
> +frame_buffer_close (rtems_device_major_number major,
> + rtems_device_minor_number minor, void *arg)
> +{
> + /* restore previous state. for VGA this means return to text mode.
> + * leave out if graphics hardware has been initialized in
> + * frame_buffer_initialize() */
> + _Atomic_Flag_clear(&driver_mutex, ATOMIC_ORDER_RELEASE);
> + memset ((void *)fb_fix_info.smem_start, 0, fb_fix_info.smem_len);
> + return RTEMS_SUCCESSFUL;
> +}
> +
> +/*
> + * fbds device driver read operation.
> + */
> +
> +rtems_device_driver
> +frame_buffer_read (rtems_device_major_number major,
> + rtems_device_minor_number minor, void *arg)
> +{
> + rtems_libio_rw_args_t *rw_args = (rtems_libio_rw_args_t *)arg;
> + rw_args->bytes_moved =
> + ((rw_args->offset + rw_args->count) > fb_fix_info.smem_len ) ?
> + (fb_fix_info.smem_len - rw_args->offset) :rw_args->count;
> + memcpy( rw_args->buffer,
> + (const void *) (fb_fix_info.smem_start + rw_args->offset),
> + rw_args->bytes_moved);
> + return RTEMS_SUCCESSFUL;
> +}
> +
> +/*
> + * fbds device driver write operation.
> + */
> +
> +rtems_device_driver
> +frame_buffer_write (rtems_device_major_number major,
> + rtems_device_minor_number minor, void *arg)
> +{
> + rtems_libio_rw_args_t *rw_args = (rtems_libio_rw_args_t *)arg;
> + rw_args->bytes_moved =
> + ((rw_args->offset + rw_args->count) > fb_fix_info.smem_len ) ?
> + (fb_fix_info.smem_len - rw_args->offset) : rw_args->count;
> + memcpy( (void *) (fb_fix_info.smem_start + rw_args->offset),
> + rw_args->buffer,
> + rw_args->bytes_moved);
> + return RTEMS_SUCCESSFUL;
> +}
> +
> +/*
> + * ioctl entry point.
> + */
> +
> +rtems_device_driver
> +frame_buffer_control (rtems_device_major_number major,
> + rtems_device_minor_number minor, void *arg)
> +{
> + rtems_libio_ioctl_args_t *args = arg;
> +
> + /* XXX check minor */
> +
> + switch (args->command) {
> + case FBIOGET_VSCREENINFO:
> + memcpy (args->buffer, &fb_var_info, sizeof (fb_var_info));
> + args->ioctl_return = 0;
> + break;
> + case FBIOGET_FSCREENINFO:
> + memcpy (args->buffer, &fb_fix_info, sizeof (fb_fix_info));
> + args->ioctl_return = 0;
> + break;
> + case FBIOGETCMAP:
> + args->ioctl_return = 0;
> + break;
> + case FBIOPUTCMAP:
> + args->ioctl_return = 0;
> + break;
> +
> + default:
> + args->ioctl_return = 0;
> + break;
> +
> + }
> + return RTEMS_SUCCESSFUL;
> +}
> diff --git a/c/src/lib/libbsp/arm/raspberrypi/include/bsp.h
> b/c/src/lib/libbsp/arm/raspberrypi/include/bsp.h index 7cb9e70..0bc5f99
> 100644
> --- a/c/src/lib/libbsp/arm/raspberrypi/include/bsp.h
> +++ b/c/src/lib/libbsp/arm/raspberrypi/include/bsp.h
> @@ -34,6 +34,8 @@ extern "C" {
>
> #define BSP_FEATURE_IRQ_EXTENSION
>
> +#define RPI_L2_CACHE_ENABLE 1
> +
> #define BSP_GPIO_PIN_COUNT 32
> #define BSP_GPIO_PINS_PER_BANK 32
> #define BSP_GPIO_PINS_PER_SELECT_BANK 10
> diff --git a/c/src/lib/libbsp/arm/raspberrypi/startup/bspgetworkarea.c
> b/c/src/lib/libbsp/arm/raspberrypi/startup/bspgetworkarea.c new file mode
> 100644
> index 0000000..07a38e9
> --- /dev/null
> +++ b/c/src/lib/libbsp/arm/raspberrypi/startup/bspgetworkarea.c
> @@ -0,0 +1,61 @@
> +/**
> + * @file
> + *
> + * @ingroup arm_start
> + *
> + * @brief Raspberry pi workarea initialization.
> + *
> + * COPYRIGHT (c) 1989-2008.
> + * On-Line Applications Research Corporation (OAR).
> + *
> + * Copyright (c) 2011-2012 embedded brains GmbH.
> + *
> + * The license and distribution terms for this file may be
> + * found in the file LICENSE in this distribution or at
> + * http://www.rtems.org/license/LICENSE.
> + *
> + * Copyright (c) 2015 YANG Qiao
> + */
> +
> +#include <bsp.h>
> +#include <bsp/bootcard.h>
> +#include <bsp/vc.h>
> +#ifdef BSP_INTERRUPT_STACK_AT_WORK_AREA_BEGIN
> + #include <rtems/config.h>
> +#endif
> +
> +#if defined(HAS_UBOOT) && !defined(BSP_DISABLE_UBOOT_WORK_AREA_CONFIG)
> + #define USE_UBOOT
> +#endif
> +
> +extern char WorkAreaBase[];
> +
> +#ifdef USE_UBOOT
> + #include <bsp/u-boot.h>
> +#else
> + extern char RamBase[];
> + extern char RamSize[];
> +#endif
> +
> +void bsp_work_area_initialize(void)
> +{
> + uintptr_t work_base = (uintptr_t) WorkAreaBase;
> + uintptr_t ram_end;
> + bcm2835_get_arm_memory_entries arm_entry;
> + bcm2835_get_vc_memory_entries vc_entry;
> +
> + #ifdef USE_UBOOT
> + ram_end = (uintptr_t) bsp_uboot_board_info.bi_memstart +
> + bsp_uboot_board_info.bi_memsize;
> + #else
> + ram_end = (uintptr_t)RamBase + (uintptr_t)RamSize;
> + #endif
> +
> + #ifdef BSP_INTERRUPT_STACK_AT_WORK_AREA_BEGIN
> + work_base += rtems_configuration_get_interrupt_stack_size();
> + #endif
> +
> + bcm2835_mailbox_get_vc_memory(&vc_entry);
> + ram_end = ram_end>vc_entry.base? vc_entry.base: ram_end;
> + bsp_work_area_initialize_default( (void *) work_base, ram_end -
> work_base ); +}
OK, but there should be reflected space reserved
for translation table table. It is defined as
bsp_translation_table_base = ORIGIN (RAM_MMU)
> diff --git a/c/src/lib/libbsp/arm/raspberrypi/startup/linkcmds
> b/c/src/lib/libbsp/arm/raspberrypi/startup/linkcmds index f1ad11c..81d4f8d
> 100644
> --- a/c/src/lib/libbsp/arm/raspberrypi/startup/linkcmds
> +++ b/c/src/lib/libbsp/arm/raspberrypi/startup/linkcmds
> @@ -37,8 +37,9 @@
> --- a/c/src/lib/libbsp/arm/raspberrypi/startup/linkcmds
> +++ b/c/src/lib/libbsp/arm/raspberrypi/startup/linkcmds
> @@ -37,8 +37,9 @@
>
> MEMORY {
> VECTOR_RAM (AIW) : ORIGIN = 0x0 , LENGTH = 0x8000
> - RAM (AIW) : ORIGIN = 0x00008000, LENGTH = 128M - 48K
> - RAM_MMU (AIW) : ORIGIN = 128M - 16k, LENGTH = 16k
> + GPU_RAM (AIW) : ORIGIN = 256M - 64M, LENGTH = 64M
> + RAM (AIW) : ORIGIN = 0x00008000, LENGTH = 256M - 64M -
48K
> + RAM_MMU (AIW) : ORIGIN = 256M - 64M - 16k, LENGTH = 16k
> }
There is significant problem in this LD script because you reserve
space for translation table RAM_MMU at the end of the memory
and if I understand to the VideoCore memory division right then
it means that MMU translation table can be rewritten by VideoCore
at any time. RAM_MMU has to be in the area owned by CPU for all cases.
Because memory division is dynamic anyway I would left VideoCore memory
out of the LD script. We can expect that VideoCore cannot take (cannot
should not be configured) more than rest from 64 MB or left script intact
if we consider that 128 has to be left for CPU.
For 64 MB case
MEMORY {
VECTOR_RAM (AIW) : ORIGIN = 0x0 , LENGTH = 0x8000
RAM (AIW) : ORIGIN = 0x00008000, LENGTH = 64M - 48K
RAM_MMU (AIW) : ORIGIN = 64M - 16k, LENGTH = 16k
}
Then VideoCore is asked to provide its memory start address (CPU Limit)
ten we know that area
WorkAreaBase to 64M - 16k can be used for work area
64M - 16k to 64M is reserved for page/translation table
64M to ram_end can again be added to workarea
But that requires to register two separate blocks to memory allocator.
Probably Joel or Gedare can guide us how that can be achieved
but for case of configuration of separate objects for kernel
and user heap regions that can get even more complicated.
So I suggest next LD script change
MEMORY {
VECTOR_RAM (AIW) : ORIGIN = 0x0, LENGTH = 0x4000
RAM_MMU (AIW) : ORIGIN = 0x4000, LENGTH = 16k
RAM (AIW) : ORIGIN = 0x00008000, LENGTH = 64M
}
The area from 0x4000 to 0x7fff should be available to RTEMS
and even if ATAGs or device tree parsing is implemented then it
should not be problem because these start by default at address
0x100 and biggest found device tree binary is bcm2709-rpi-2-b.dtb
about 10 kB for now.
With this arrangement it is no problem to define
ram_end = vc_entry.base
probably with a sanity check
if (ram_end > 1 GB)
ram_end = 1 GB;
Then MMU should be setup for fixed part by
arm_cp15_start_setup_translation_table_and_enable_mmu_and_cache
then rest of the found memory which can be used by CPU is added
arm_cp15_set_translation_table_entries for 64 M to ram_end
ARMV7_MMU_DATA_READ_WRITE_CACHED
and last is added area shared with VideoCore
arm_cp15_set_translation_table_entries for 64 M to ram_end
ARMV7_MMU_DATA_READ_WRITE_CACHED
I am not sure if enabled cache is OK for this area.
It depends of state if mutual memory access coherence protocol
is defined between VideoCore and ARM core.
The latst operation is
bsp_work_area_initialize_default( (void *) work_base, ram_end - work_base );
By the way, it looks to me RAM_MMU region coverage is missing in all
instances of arm_cp15_start_mmu_config_table[] used in different BSPs.
This means that after switch to MMU enabled state the table cannot
be accessed by CPU probably. Can somebody explain me/check if is
the case?
> REGION_ALIAS ("REGION_START", RAM);
> diff --git a/c/src/lib/libbsp/arm/raspberrypi/startup/mminit.c
> b/c/src/lib/libbsp/arm/raspberrypi/startup/mminit.c new file mode 100644
> index 0000000..e012060
> --- /dev/null
> +++ b/c/src/lib/libbsp/arm/raspberrypi/startup/mminit.c
> @@ -0,0 +1,42 @@
> +/*
> + * Copyright (c) 2015 Yang Qiao
> + * based on work by:
> + * 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.org/license/LICENSE.
> + */
> +
> +#define ARM_CP15_TEXT_SECTION BSP_START_TEXT_SECTION
> +
> +#include <bsp/start.h>
> +#include <bsp/arm-cp15-start.h>
> +#include <bsp/linker-symbols.h>
> +#include <bsp/mm.h>
> +#include <rtems/fb.h>
> +
> +extern int raspberrypi_get_var_screen_info( struct fb_var_screeninfo *info
> ); +
> +BSP_START_TEXT_SECTION void bsp_memory_management_initialize(void)
> +{
> + uint32_t ctrl = arm_cp15_get_control();
> +
> + ctrl |= ARM_CP15_CTRL_AFE | ARM_CP15_CTRL_S | ARM_CP15_CTRL_XP;
> +
> + struct fb_fix_screeninfo fb_fix_info;
> + raspberrypi_get_fix_screen_info(&fb_fix_info);
> +
> + arm_cp15_start_setup_translation_table_and_enable_mmu_and_cache(
> + ctrl,
> + (uint32_t *) bsp_translation_table_base,
> + ARM_MMU_DEFAULT_CLIENT_DOMAIN,
> + &arm_cp15_start_mmu_config_table[0],
> + arm_cp15_start_mmu_config_table_size
> + );
> +
> + arm_cp15_set_translation_table_entries(fb_fix_info.smem_start,
> + fb_fix_info.smem_start +
> + fb_fix_info.smem_len,
> + ARMV7_MMU_DATA_READ_WRITE_CACHED);
> +}
Best wishes,
Pavel
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