source: rtems/c/src/lib/libbsp/arm/tms570/pom/tms570-pom.c @ 9935c23

5
Last change on this file since 9935c23 was 870ff8e9, checked in by Pavel Pisa <pisa@…>, on 11/12/15 at 22:11:31

bsp/tms570: use POM only when application image does not start at address 0.

Parameters overlay module is initialized and cleared first.
It is used later to replace exception target vectors
only if that is required.

The application loader code with CPU and SDRAM setup
code has to provide well defined pattern of instructions
at addresses 0x00000000 and 0x0000001f, because only data
read accesses can be processed reliably by POM. The expected
instruction pattern can be seen in the next example

https://github.com/hornmich/tms570ls3137-hdk-sdram/blob/master/SDRAM_SCI_configuration/source/sys_intvecs.asm

Comments with detailed description of code, background
and reasons for selected approach have been included
in TMS570 bsp startup code.

Signed-off-by: Pavel Pisa <pisa@…>
Signed-off-by: Premysl Houdek <kom541000@…>

  • Property mode set to 100644
File size: 4.3 KB
Line 
1/**
2 * @file tms570-pom.c
3 *
4 * @ingroup tms570
5 *
6 * @brief TMS570 Parameter Overlay Module functions definitions.
7 */
8
9 /*
10 * Copyright (c) 2014 Pavel Pisa <pisa@cmp.felk.cvut.cz>
11 *
12 * Czech Technical University in Prague
13 * Zikova 1903/4
14 * 166 36 Praha 6
15 * Czech Republic
16 *
17 * The license and distribution terms for this file may be
18 * found in the file LICENSE in this distribution or at
19 * http://www.rtems.org/license/LICENSE.
20 */
21
22#include <stdint.h>
23#include <bsp/tms570-pom.h>
24#include <bsp/linker-symbols.h>
25#include <rtems/score/armv4.h>
26#include <bsp.h>
27
28/*
29 * Placement of exceptions target addresses in memory
30 * when insructions with opcode 0xe59ff018
31 *      ldr pc, [pc, #0x18]
32 * are used to fill ARM exception vectors area
33 */
34typedef struct{
35  uint32_t reserved1;
36  uint32_t except_addr_undef;
37  uint32_t except_addr_swi;
38  uint32_t except_addr_prefetch;
39  uint32_t except_addr_abort;
40  uint32_t reserved2;
41  uint32_t except_addr_irq;
42  uint32_t except_addr_fiq;
43}vec_remap_table;
44
45void bsp_block_on_exception(void);
46
47void bsp_block_on_exception(void){
48  while(1);
49}
50
51extern char bsp_int_vec_overlay_start[];
52
53/*
54 * Global overlay target address holds shared MSB bits for all regions
55 * It is set to linker RAM_INT_VEC region - i.e. area reserved
56 * at internal SRAM memory start, address 0x08000000
57 */
58uint32_t pom_global_overlay_target_address_start =
59                                 (uintptr_t)bsp_int_vec_overlay_start;
60
61/**
62 * @brief initialize and clear parameters overlay module (POM)
63 *
64 * clears all remap regions. The actual POM enable is left to the first user.
65 *
66 * @retval Void
67 */
68void tms570_initialize_and_clear(void)
69{
70  int i;
71
72  TMS570_POM.GLBCTRL = 0 | (TMS570_POM_GLBCTRL_OTADDR(~0) &
73                            pom_global_overlay_target_address_start);
74
75  for ( i = 0; i < TMS570_POM_REGIONS; ++i ) {
76    TMS570_POM.REG[i].REGSIZE = TMS570_POM_REGSIZE_SIZE(TMS570_POM_REGSIZE_DISABLED);
77  }
78}
79
80/**
81 * @brief remaps vector table
82 *
83 * transfer the rtems start vector table to address 0x0
84 *
85 * @retval Void
86 */
87void tms570_pom_remap(void)
88{
89  uint32_t vec_overlay_start = pom_global_overlay_target_address_start;
90
91  /*
92   * Copy RTEMS the first level exception processing code
93   * to RAM area which can be used for later as POM overlay
94   * of Flash vectors. The code is expected to have for of eight
95   *   ldr pc, [pc,#0x18]
96   * instructions followed by eight words with actual exception
97   * service routines target addresses. This is case of RTEMS default
98   * table found in
99   *   c/src/lib/libbsp/arm/shared/start/start.S
100   */
101  memcpy((void*)vec_overlay_start, bsp_start_vector_table_begin, 64);
102
103  #if 0
104  {
105    /* Fill exception table by catch error infinite loop for debugging */
106    vec_remap_table* vec_table = (vec_remap_table*)(vec_overlay_start+32);
107    vec_table->except_addr_undef = (uint32_t)bsp_block_on_exception;
108    vec_table->except_addr_swi = (uint32_t)bsp_block_on_exception;
109    vec_table->except_addr_prefetch = (uint32_t)bsp_block_on_exception;//_ARMV4_Exception_prefetch_abort;
110    vec_table->except_addr_abort = (uint32_t)bsp_block_on_exception;//_ARMV4_Exception_data_abort;
111    vec_table->except_addr_irq = (uint32_t)_ARMV4_Exception_interrupt;
112    vec_table->except_addr_fiq = (uint32_t)bsp_block_on_exception;//_ARMV4_Exception_interrupt;
113  }
114  #endif
115
116  /*
117   * The overlay vectors replacement area cannot be used directly
118   * to replace jump instructions on start of Flash because instruction
119   * fetch through POM is not reliable supported (works in most times
120   * but sometimes fails).
121   * Area of 64 bytes starting at address 0x00000040 is replaced.
122   * This way target addresses are placed between 0x00000060
123   * and 0x0000007F. If boot loader startup code contains instructions
124   *   ldr pc,[pc,#0x58]
125   * (opcode 0xe59ff058) then the jump target addresses are replaced
126   * by pointers to actual RTEMS exceptions service functions.
127   */
128  TMS570_POM.REG[0].PROGSTART = TMS570_POM_PROGSTART_STARTADDRESS(64);
129  TMS570_POM.REG[0].OVLSTART = TMS570_POM_OVLSTART_STARTADDRESS(vec_overlay_start);
130  TMS570_POM.REG[0].REGSIZE = TMS570_POM_REGSIZE_SIZE(TMS570_POM_REGSIZE_64B);
131  TMS570_POM.GLBCTRL = TMS570_POM_GLBCTRL_ON_OFF(0xa) |
132                       TMS570_POM_GLBCTRL_ETO(0xa) |
133                       (TMS570_POM_GLBCTRL_OTADDR(~0) &
134                        pom_global_overlay_target_address_start);
135}
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