AT91Bootstrap
1. Introduction
The AT91Bootstrap application is a first level bootloader for Atmel® AT91SAM9 ARM®
Thumb®- based microcontrollers. It is a modular application and thus can be used to
customize the framework for a particular deployment strategy. AT91Bootstrap also
provides clear examples, for a particular device, on how to perform basic static configurations, such as PMC and PIOs. AT91Bootstrap can be easily configured using a
higher level protocol.
AT91Bootstrap integrates several sets of algorithms:
AT91 ARM
Thumb
Microcontrollers
Application Note
• Device initialization such as clock speed configuration, PIO settings, etc.
• Peripheral drivers such as PIO, PMC, SDRAMC, etc.
• Physical media algorithms such as DataFlash®, NANDFlash, Parallel Flash, etc.
• File System drivers such as JFFS2, FAT, etc.
• Compression and Cipher algorithms
• Application Launcher for ELF, Linux®, etc.
For example, using this set of algorithms, it is possible to obtain a basic bootloader
that is located in DataFlash and is copied to internal SRAM by SAM-BA™ Boot. The
bootloader performs the processor initialization (PLLs, PIOs, SDRAMC, SPI), loads UBoot from DataFlash sectors to SDRAM and then jumps to it.
6277B–ATARM–05-Dec-06
2. Peripheral Drivers
Before using AT91SAM peripherals, the AIC, PMC and PIO must be configured to enable
access to the device resources of the peripheral (e.g., clock, pins, processor interrupt). All of
these functions are located in the driver directory.
2.1
PIO
The following general purpose routines are used to interface with the PIO controller.
The PIO driver associates a unique number (pin_number) to each PIO line for all PIO controllers. Thus PIOA controller handles pin_number from 0 to 31, PIOB controller handles
pin_number from 32 to 61, PIOC controller handles pin from 62 to 95.
A macro that returns the index of the PIO controller for a given pin_number is straightforward:
/* Convert Pin Number into PIO controller index */
static inline unsigned pin_to_controller(unsigned pin)
{
return
(pin) / 32;
}
Note:
2.1.1
This implementation approaches the standard open source implementation found in Linux to set
an example.
pio_desc Structure
The pio_desc C structure is used to specify the PIO configuration for a pin. An array of pio_desc
structures is given as an argument to the pio_setup() function. For each element of the array, the
pio_setup() function configures the PIO controller depending on the pin configuration. This array
must be ended by a NULL element. pio_desc instances can be declared as const elements to be
residant in CODE segments.
Table 2-1.
Field
Type
Description
pin_name
const char *
If NULL, mark the last element of an array
pin_num
unsigned int
pin_number as described in the introduction
dft _value
unsigned int
Default value when configured as an output
1 = HIGH; 0 = LOW
attribute
unsigned char
type
enum
Table 2-2.
2
pio_desc Structure
As defined in the pio_type enumeration
pio_type Enumeration
Name
Description
PIO_PERIPH_A
The pin corresponds to the peripheral A signal
PIO_PERIPH_B
The pin corresponds to the peripheral B signal
PIO_INPUT
The pin is in input
PIO_OUTPUT
The pin is in output
Application Note
6277B–ATARM–05-Dec-06
Application Note
Table 2-3.
PIO Attributes
Name
Value
Description
PIO_DEFAULT
0
Default configuration
PIO_PULLUP
(1 << 0)
Enable the PIO internal pull-up
PIO_DEGLITCH
(1 << 1)
Enable the PIO glitch filter (mostly used with IRQ handling)
PIO_OPENDRAIN
(1 << 2)
Enable the PIO multi-driver.
This is only valid for output and allows the output pin to run as
an open drain output.
In the following example, pins 9 and 10 of the PIO controller A are configured to be connected
with the DBGU internal signals RXD and TXD:
const struct pio_desc hw_pio[] = {
{"RXD", AT91C_PIN_PA(9), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"TXD", AT91C_PIN_PA(10), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"", 0, 0, PIO_DEFAULT, PIO_PERIPH_A},
};
This array can be used as an argument to the pio_setup() function.
2.1.2
pio_setup() Function
This function configures PIOs depending on the pin description given as an argument.
Note:
If a pin is declared as being an input, the clock of the corresponding PIO is not automatically configured and must be previously enabled in the PMC.
Table 2-4.
pio_setup() Function
int pio_setup (const struct pio_desc *pio_desc)
Input Arguments
Name
Description
pio_desc
Pointer to a pio_desc array ended by a NULL element
Output Result
2.1.2.1
Type
Description
int
Return the number of pin configured
Example
In the following example, pins are configured to output PCK signals on the pins controlled by the
pin 7 and 8 of the PIO controller A.
const struct pio_desc hw_pio[] = {
{"PCK0", AT91C_PIN_PA(7), 0, PIO_DEFAULT, PIO_PERIPH_B},
{"PCK1", AT91C_PIN_PA(8), 0, PIO_DEFAULT, PIO_PERIPH_B},
{"", 0, 0, PIO_DEFAULT, PIO_PERIPH_A},
};
/* Configure the PIO controller to output PCK0 */
pio_setup(hw_pio);
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2.1.3
pio_get_value() Function
This function is used to capture the state of the corresponding pin associated with the
pin_number given in the argument.
The pin must have been configured in input as previously described.
Note:
The clock of the corresponding PIO must be enabled in the PMC in order to have a correct value
returned by this function.
Table 2-5.
pio_get_value() Function
int pio_get_value(unsigned pin)
Input Arguments
Name
Description
pin
pin number as decribed above
Output Result
2.1.4
Type
Description
int
0: the pin is low
1: the pin is high
-1 if the pin-number does not exist
pio_set_value() Function
This function is used to force the state of the pin associated with the pin_number given in the
argument.
The pin must have been configured in output as previously described.
Table 2-6.
pio_get_gpio_value() Function
int pio_set_value(unsigned pin, int value)
Input Arguments
Name
Description
pin
Pin number as decribed above
value
0 forces the corresponding pin level to low
Else forces the corresponding pin to high
Output Result
2.1.4.1
Type
Description
int
If the pin does not exist, returns -1
Else returns 0
Example
In the following example, pins corresponding to PIO_TEST_OUT and PIO_TEST_IN are connected by an external strap. PIO_TEST_OUT is configured in output and its default state is low.
PIO_TEST_IN is configured in input. It is used to check the PIO_TEST_OUT level.
/* Device specific... */
#define PIO_TEST_OUT AT91C_PIN_PA(7)
#define PIO_TEST_IN AT91C_PIN_PA(8)
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Application Note
/* Device non specific... */
const struct pio_desc hw_pio[] = {
{"TEST_OUT", PIO_TEST_OUT, 0, PIO_DEFAULT, PIO_OUTPUT},
{"TEST_IN", PIO_TEST_IN, 0, PIO_DEGLITCH, PIO_INPUT},
{"", 0, 0, PIO_DEFAULT, PIO_PERIPH_A},
};
/* Configure the PIO controller to output PCK0 */
pio_setup(hw_pio);
/* Test the default value */
if (pio_get_value(PIO_TEST_IN) == 1)
return 0; /* Return failed */
/* Force a high level on PIO_TEST_OUT pin */
pio_set_value(PIO_TEST_OUT, 1);
/* Test the default value */
if (pio_get_value(PIO_TEST_IN) == 0)
return 0; /* Return failed */
return 1; /* Success */
2.2
PMC
The goal of these routines is to configure the Clock Generator (CKGR) and the Power Management Controller (PMC) in order to clock the core and the peripherals with the correct
frequencies.
In order to reduce mathematical operations such as divisions, most of the configuration is done
though constant macros.
Constant values can be generated with an external tool from the device specification and application requirements.
It allows a clear separation from the configuration algorithm with the configuration values:
/* Automatically generated using ... */
#define PMC_PLLAR 0x12345678 /* MOSC = 18.423Mhz,MUL = ,DIV = */
#define PMC_PLLBR 0x12345678 /* MOSC = 18.423Mhz, MUL =,DIV = */
#define PMC_MCKR 0x12345678 /* MCK = PLLA */
#define PLL_TIMEOUT 1000000
/* Configure PLLA */
if (!pmc_cfg_plla(PMC_PLLAR, PLL_TIMEOUT))
goto pmc_error;
/* Switch MCK on PLLA output PCK = PLLA = 2 * MCK */
if (!pmc_cfg_mck(PMC_MCKR, PLL_TIMEOUT))
goto pmc_error;
/* Configure PLLB */
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if (!pmc_cfg_pllb(PMC_PLLBR, PLL_TIMEOUT))
goto pmc_error;
pmc_error:
/* Reset the device*/
2.2.1
pmc_cfg_plla() Function
This function configures the PMC_PLLAR register with the value provided in argument and waits
for the lock of the PLL. If the timeout is reached, -1 is returned.
Table 2-7.
pmc_cfg_plla()function
int pmc_cfg_plla(unsigned int pmc_pllar, unsigned int timeout)
Input Arguments
Name
Description
pmc_pllar
Value to indicate in the PMC_PLLAR Register
timeout
Initial value of a timeout counter
Output Result
2.2.2
Type
Description
int
-1 Timeout error
0 Success
pmc_cfg_pllb() Function
This function configures the PMC_PLLBR register with the value provided in argument and waits
for the lock of the PLL. If the timeout is reached, -1 is returned.
Table 2-8.
pmc_cfg_pllb()function
int pmc_cfg_pllb(unsigned int pmc_pllbr, unsigned int timeout)
Input Arguments
Name
Description
pmc_pllbr
Value to indicate in the PMC_PLLBR Register
timeout
Initial value of a timeout counter
Output Result
6
Type
Description
int
-1 Timeout error
0 Success
Application Note
6277B–ATARM–05-Dec-06
Application Note
2.2.3
pmc_cfg_mck() Function
This function configures the PMC_MCKR register with the value provided in argument and waits
for MCK to be ready. If the timeout is reached, -1 is returned.
Table 2-9.
pmc_cfg_mck()function
int pmc_cfg_mck(unsigned int pmc_mckr, unsigned int timeout)
Input Arguments
Name
Description
pmc_mckr
Value to indicate in the PMC_MCKR Register
timeout
Initial value of a timeout counter
Output Result
2.2.4
Type
Description
int
-1 Timeout error
0 Success
pmc_cfg_pck() Function
This function configures PMC_PCKRx register with the value provided in argument and waits for
PCKx flag to be ready.
Table 2-10.
pmc_cfg_mck()function
int pmc_cfg_mck(unsigned char x, unsigned int clk_sel, unsigned int prescaler)
Input Arguments
Name
Description
x
PCKx
clk_sel
Clock Source Selection (CSS field of PMC_PCKx register)
prescaler
PCK Prescaler (PRES field of PMC_PCKx register)
Output Result
2.3
Type
Description
int
0 Success
SDRAMC
The goal of these routines is to configure the SDRAM Controller (SDRAMC) in order to use the
SDRAM at the specified frequency.
2.3.1
Prerequisite
• CFG_SDRAM and CFG_HW_INIT flags must be defined in your board project header file.
Example: Define these flags in board/at91sam9260ek/dataflash/at91sam9260ek.h header file.
• Create a function sdramc_hw_init() in your board source file.
Example: Define this function in board/at91sam9260ek/at91sam9260ek.c source file.
2.3.2
sdramc_hw_init() Function
This function must be implemented in your board source file. It configures the PIOs used by the
SDRAMC controller.
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Prototype: void sdramc_hw_init(void)
Note:
2.3.2.1
Even if no PIO needs to be configured, the function has to be defined as empty.
Example
This is the function defined in board/at91sam9260ek/at91sam9260ek.c source file.
#ifdef CFG_SDRAM
void sdramc_hw_init(void)
{
const struct pio_desc sdramc_pio[] = {
{"D0", AT91C_PIN_PC(16), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D1", AT91C_PIN_PC(17), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D2", AT91C_PIN_PC(18), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D3", AT91C_PIN_PC(19), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D4", AT91C_PIN_PC(20), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D5", AT91C_PIN_PC(21), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D6", AT91C_PIN_PC(22), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D7", AT91C_PIN_PC(23), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D8", AT91C_PIN_PC(24), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D9", AT91C_PIN_PC(25), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D10", AT91C_PIN_PC(26), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D11", AT91C_PIN_PC(27), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D12", AT91C_PIN_PC(28), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D13", AT91C_PIN_PC(29), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D14", AT91C_PIN_PC(30), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"D15", AT91C_PIN_PC(31), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"", 0, 0, PIO_DEFAULT, PIO_PERIPH_A},
};
/* Configure the PIO controller to enable 32-bits SDRAM */
pio_setup(sdramc_pio);
}
#endif
2.3.3
sdramc_init() Function
This function configures the SDRAM Controller with the values provided in the argument.
Table 2-11.
sdramc_init() Function
int sdramc_init(unsigned int sdramc_cr, unsigned int sdramc_tr)
Input Arguments
Name
Description
sdramc_cr
Value to indicate in the SDRAMC_CR Register
sdramc_tr
Value to indicate in the SDRAMC_TR Register
Output Result
Type
Description
int
0 Success
Note:
8
sdramc_init() function calls sdramc_hw_init() function
Application Note
6277B–ATARM–05-Dec-06
Application Note
2.4
DBGU
The goal of these routines is to configure the Debug Unit (DBGU) in order to send a message on
a console.
2.4.1
Prerequisite
• CFG_DEBUG and CFG_HW_INIT flags must be defined in your board project header file.
Example: Define these flags in board/at91sam9260ek/dataflash/at91sam9261ek.h header file.
2.4.2
dbg_init() Function
This function configures the Debug Unit with the provided baudrate value.
Table 2-12.
dbg_init() Function
void dbg_init(unsigned int baudrate)
Input Arguments
2.4.3
Name
Description
baudrate
Value to indicate in the US_BRGR Register
dbg_print() Function
This function sends a message on a console through the Debug Unit.
Table 2-13.
dbg_print() Function
void dbg_print(const char * ptr)
Input Arguments
2.4.3.1
Name
Description
ptr
Pointer to the string to send.
Example
dbg_print(”Send this message”);
2.5
2.5.1
DataFlash
Prerequisite
• CFG_DATAFLASH flag must be defined in your board project header file.
Example: Define this flag in board/at91sam9260ek/dataflash/at91sam9260ek.h header file.
• Create a function df_hw_init() in your board source file
Example: Define this function in board/at91sam9260ek/at91sam9260ek.c source file.
2.5.2
df_hw_init() Function
This function must be implemented in your board source file. It configures the PIOs used by the
SPI DataFlash.
Prototype: void df_hw_init(void)
Note:
Even if no PIO needs to be configured, the function has to be defined as empty.
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2.5.2.1
Example
This is the function defined in board/at91sam9260ek/at91sam9260ek.c source file.
#ifdef CFG_DATAFLASH
void df_hw_init(void)
{
const struct pio_desc df_pio[] = {
{"MISO", AT91C_PIN_PA(0), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"MOSI", AT91C_PIN_PA(1), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"SPCK", AT91C_PIN_PA(2), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"NPCS0", AT91C_PIN_PA(3), 0, PIO_DEFAULT, PIO_PERIPH_A},
{"", 0, 0, PIO_DEFAULT, PIO_PERIPH_A},
};
/* Configure the PIO controller to enable SPI DataFlash*/
pio_setup(df_pio);
}
#endif
2.5.3
load_df() Function
This function configures the SPI Interface and downloads an image stored in DataFlash at the
defined JUMP_ADDR. If an error happens during the process, -1 is returned.
Table 2-14.
load_df()function
int load_df(unsigned int pcs, unsigned int img_addr, unsigned int img_size)
Input Arguments
Name
Description
pcs
Select corresponding SPI Chip Select
img_addr
Image Address in the DataFlash
img_size
Image Size in the DataFlash
Output Result
Type
Description
int
-1 Error
0 Success
Note:
2.6
2.6.1
load_df() function calls df_hw_init() function
NAND Flash
Prerequisite
• CFG_NANDFLASH flag must be defined in your board project header file.
Example: Define this flag in board/at91sam9260ek/nandflash/at91sam9260ek.h header file.
• Create nandflash_hw_init() and nandflash_cfg_16bits_dbw_init() in your board source file.
Example: Define this function in board/at91sam9260ek/at91sam9260ek.c source file.
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Application Note
2.6.2
nandflash_hw_init() Function
This function has to be implemented in your board source file.
It configures:
• PIOs used by the NAND Flash
• SMC timings
• HMatrix or Chip Configuration User Interface
Prototype: void nandflash_hw_init(void)
2.6.2.1
Example
This is the function defined in board/at91sam9260ek/at91sam9260ek.c source file.
#ifdef CFG_NANDFLASH
void nandflash_hw_init(void)
{
const struct pio_desc nand_pio[] = {
{"RDY_BSY", AT91C_PIN_PC(13), 0, PIO_PULLUP, PIO_PERIPH_A},
{"NANDCS", AT91C_PIN_PC(14), 0, PIO_PULLUP, PIO_PERIPH_A},
{"", 0, 0, PIO_DEFAULT, PIO_PERIPH_A},
};
/* Setup Smart Media, first enable the address range of CS3 in HMATRIX
user interface */
writel(readl(AT91C_BASE_CCFG + CCFG_EBICSA) | AT91C_EBI_CS3A_SM,
AT91C_BASE_CCFG + CCFG_EBICSA);
/* Configure SMC CS3 */
writel((AT91C_SM_NWE_SETUP | AT91C_SM_NCS_WR_SETUP | AT91C_SM_NRD_SETUP|
AT91C_SM_NCS_RD_SETUP), AT91C_BASE_SMC + SMC_SETUP3);
writel((AT91C_SM_NWE_PULSE | AT91C_SM_NCS_WR_PULSE | AT91C_SM_NRD_PULSE|
AT91C_SM_NCS_RD_PULSE), AT91C_BASE_SMC + SMC_PULSE3);
writel((AT91C_SM_NWE_CYCLE | AT91C_SM_NRD_CYCLE),
AT91C_BASE_SMC + SMC_CYCLE3);
writel((AT91C_SMC_READMODE | AT91C_SMC_WRITEMODE |
AT91C_SMC_NWAITM_NWAIT_DISABLE | AT91C_SMC_DBW_WIDTH_EIGTH_BITS|
AT91C_SM_TDF), AT91C_BASE_SMC + SMC_CTRL3);
/* Configure the PIO controller */
writel((1 << AT91C_ID_PIOC), PMC_PCER + AT91C_BASE_PMC);
pio_setup(nand_pio);
}
#endif
2.6.3
nandflash_cfg_16bits_dbw_init() Function
This function must be implemented in your board source file. It is only used when a 16-bit NAND
Flash has been detected by the bootloader.
It configures the SMC in 16-bit Data Bus Width mode.
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2.6.3.1
Example
This is the function defined in board/at91sam9260ek/at91sam9260ek.c source file.
#ifdef CFG_NANDFLASH
void nandflash_cfg_16bits_dbw_init(void)
{
writel(readl(AT91C_BASE_SMC + SMC_CTRL3) |
AT91C_SMC_DBW_WIDTH_SIXTEEN_BITS, AT91C_BASE_SMC + SMC_CTRL3);
}
#endif
2.6.4
load_nandflash() Function
This function configures the NANDFlash Interface and downloads an image stored in NAND
Flash at the defined JUMP_ADDR. If an error happens during the process, -1 is returned.
Table 2-15.
load_nandflash()function
int load_nandflash(unsigned int img_addr, unsigned int img_size)
Input Arguments
Name
Description
img_addr
Image Address in the NANDFlash
img_size
Image Size in the NANDFlash
Output Result
Type
Description
int
-1 Error
0 Success
Note:
2.6.5
2.6.5.1
load_nandflash() function calls nandflash_hw_init() function
NAND Flash Features
Large Blocks vs. Small Blocks
To summarize, NAND Flash blocks are divided into two categories:
• Large Block NAND Flash: parts bigger than 1 Gbit
• Small Block NAND Flash: parts smaller than 1 Gbit
Note:
For 1 Gbit NAND Flash parts, it is recommended to verify in the NAND Flash datasheet if the part
is considered as a Small or Large Block part.
NAND Flash Large Block algorithms are used by default.
To use NAND Flash Small Block algorithms, NANDFLASH_SMALL_BLOCKS flag must be
defined in your board project header file.
Example: Define this flag in board/at91sam9260ek/nandflash/at91sam9260ek.h header file.
#define CFG_NANDFLASH /* Enable DataFlash Download */
#define NANDFLASH_SMALL_BLOCKS /*Small Block NandFlash used */
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Application Note
2.6.5.2
Adding a New NAND Flash Support in AT91Bootstrap
NAND Flash IDs and information are located in the include/nand_ids.h header file with the following format:
typedef struct SNandInitInfo
{
unsigned int uNandID; /* Nand Chip ID */
unsigned int uNandNbBlocks;
/* Total Number of Blocks */
unsigned int uNandBlockSize; /* Block Size*/
unsigned int uNandSectorSize;/* Page Size */
unsigned int uNandSpareSize; /* Number of Spare bytes for a Page */
unsigned int uNandBusWidth; /* 0=8 bits /// 1=16 bits */
char
name[40]; /* Nand Name */
} SNandInitInfo, *PSNandInitInfo;
Add new NAND Flash information in the NandFlash_InitInfo[] table to add support for your new
NAND Flash device.
3. Device Hardware Initialization
The C startup routine is the same for all the AT91SAM devices. This routine performs the following actions before it jumps to the main function:
1. Initialize the Main Oscillator (if not already done).
2. Switch MCK to the main oscillator (only if MCK is at Slow Clock).
3. C VARIABLES INIT.
4. Branch to the C code.
This routine is given in the crt0_gnu.s assembly file.
Note:
3.1
To reduce the boot time, the main oscillator is enabled as soon as possible.
AT91SAM9260 Initialization
The following operations are performed during the AT91SAM9260 hardware initialization:
• Disable Watchdog
• Configure PLLA
• Switch MCK to PLLA/2
• Configure PLLB
• Enable I-Cache
• Configure PIOs
• Configure Matrix (only when using SDRAMC)
3.1.1
Generating DataFlashBoot
The following example shows how to to generate a bootstrap in DataFlash to launch U-Boot.
The required flags are defined in the board/at91sam9260ek/dataflash/at91sam9260ek.h header
file.
/* Download Settings */
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#define IMG_ADDR 0x8000 /* U-Boot Address in DataFlash */
#define IMG_SIZE 0x30000 /* U-Boot size in DataFlash */
#define JUMP_ADDR 0x23F00000 /* U-Boot Link Address in SDRAM */
/* BootStrap Settings */
#undef CFG_DEBUG /* Disable DBGU messages (Recommended - see code size
part below) */
#define CFG_DATAFLASH /* Enable DataFlash Download */
#define CFG_HW_INIT /* Enable Low Level Configuration (PIOs,PMC...)*/
#define CFG_SDRAM /* Enable SDRAM Controller Configuration */
Some project parameters needs to be defined in the Makefile. Makefile is located in the
board/at91sam9260ek/dataflash/ project directory.
# DataFlashBoot Configuration for AT91SAM9260EK
# Target name (case sensitive!!!)
TARGET=AT91SAM9260
# Board name (case sensitive!!!)
BOARD=at91sam9260ek
# Link Address and Top_of_Memory
LINK_ADDR=0x200000
# Stack pointer
TOP_OF_MEMORY=0x301000
# Name of current directory (case sensitive!!!)
PROJECT=dataflash
Now the project parameters are set correctly and the project can be compiled and linked.
> cd board/at91sam9260ek/dataflash
> make
Your image, named dataflash_at91sam9260ek.bin, should be ready now. Simply download the
binary file in DataFlash with SAM-BA Application for example.
3.1.2
Generating NANDFlashBoot
The following example shows how to to generate a bootstrap in NANDFlash to launch U-Boot.
The required flags are defined in the board/at91sam9260ek/nandflash/at91sam9260ek.h header
file.
/* Download Settings */
#define IMG_ADDR 0x20000 /* U-Boot Address in NandFlash */
#define IMG_SIZE 0x30000 /* U-Boot size in NandFlash */
#define JUMP_ADDR 0x23F00000 /* U-Boot Link Address in SDRAM */
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Application Note
/* BootStrap Settings */
#undef CFG_DEBUG /* Disable DBGU messages (Recommended - see code size
part below) */
#define CFG_NANDFLASH /* Enable DataFlash Download */
#undef NANDFLASH_SMALL_BLOCKS /*Large Block NandFlash used instead*/
#define CFG_HW_INIT /* Enable Low Level Configuration (PIOs,PMC...)*/
#define CFG_SDRAM /* Enable SDRAM Controller Configuration */
Some project parameters needs to be defined in the Makefile. Makefile is located in the
board/at91sam9260ek/nandflash/ project directory.
# NandFlashBoot Configuration for AT91SAM9260EK
# Target name (case sensitive!!!)
TARGET=AT91SAM9260
# Board name (case sensitive!!!)
BOARD=at91sam9260ek
# Link Address and Top_of_Memory
LINK_ADDR=0x200000
# Stack pointer
TOP_OF_MEMORY=0x301000
# Name of current directory (case sensitive!!!)
PROJECT=nandflash
Now the project parameters are set correctly and the project can be compiled and linked.
> cd board/at91sam9260ek/nandflash
> make
Your image, named nandflash_at91sam9260ek.bin, should be ready now. Simply download the
binary file in NANDFlash with SAM-BA Application for example.
3.1.3
AT91SAM9260 BootStrap Code Size Constraint
Bootstrap binary image size must be less than 4K bytes which corresponds to the internal available SRAM size for the AT91SAM9260.
Depending on the toolchain which is used, resulting code size may be higher than the allowed
4K bytes. In such a case, either update your toolchain to a more recent one or do not use the
provided gpio driver to configure SDRAM PIOs for example. Replace sdramc_hw_init() function
in board/at91sam9260/at91sam9260ek.c source file by:
#ifdef CFG_SDRAM
void sdramc_hw_init(void)
{
/* Configure the PIO controller to enable 32-bits SDRAM */
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6277B–ATARM–05-Dec-06
writel(0xFFFF0000, AT91C_BASE_PIOC + PIO_ASR(0));
writel(0xFFFF0000, AT91C_BASE_PIOC + PIO_PDR(0));
}
#endif
Note:
3.1.4
Code is less readable but it should be sufficient enough to have less than 4K bytes code size without having to re-compile a complete GCC toolchain.
AT91SAM9260-EK Bootstrap Recovery Procedure
AT91SAM9260 ROM code boots on:
• DataFlash card on NCS0
• DataFlash device on NCS1 (recovery procedure available)
• NANDFlash (recovery procedure available)
There is no jumper on DataFlash NCS1 or on NANDFlash on the AT91SAM9260-EK board and
so it is not possible to program the target unless the content of the first page of the device is
erased. A simple software recovery procedure has been implemented in AT91Bootstrap for the
AT91SAM9260-EK board.
If BP4 is pressed during the boot sequence, it is automatically detected and DataFlash first page
(or NAND Flash first block) is erased in order to boot correctly next time. The recovery procedure is as follows:
1. Press BP4 button (BP4 must be kept pressed during steps 2 and 3),
2. Press Reset button,
3. Let the application boot.
4. Release BP4.
5. Reset the board.
AT91SAM9260 ROM code should now start correctly.
3.2
AT91SAM9261 Initialization
The following operations are performed during the AT91SAM9261 hardware initialization:
• Disable Watchdog
• Configure PLLA
• Switch MCK to PLLA/2
• Configure PLLB
• Enable I-Cache
• Configure PIOs
• Configure Matrix (only when using SDRAMC)
3.2.1
Generating DataFlashBoot
The following example shows how to generate a bootstrap in DataFlash to launch U-Boot.
The required flags are defined in the board/at91sam9261ek/dataflash/at91sam9261ek.h header
file.
/* Download Settings */
#define IMG_ADDR 0x8000 /* U-Boot Address in DataFlash */
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Application Note
6277B–ATARM–05-Dec-06
Application Note
#define IMG_SIZE 0x30000 /* U-Boot size in DataFlash */
#define JUMP_ADDR 0x23F00000 /* U-Boot Link Address in SDRAM */
/* BootStrap Settings */
#undef CFG_DEBUG /* Disable DBGU messages (optional) */
#define CFG_DATAFLASH /* Enable DataFlash Download */
#define CFG_HW_INIT /* Enable Low Level Configuration (PIOs,PMC...)*/
#define CFG_SDRAM /* Enable SDRAM Controller Configuration */
Some project parameters needs to be defined in the Makefile. Makefile is located in the
board/at91sam9261ek/dataflash/ project directory.
# DataFlashBoot Configuration for AT91SAM9261EK
# Target name (case sensitive!!!)
TARGET=AT91SAM9261
# Board name (case sensitive!!!)
BOARD=at91sam9261ek
# Link Address and Top_of_Memory
LINK_ADDR=0x300000
# Stack pointer
TOP_OF_MEMORY=0x328000
# Name of current directory (case sensitive!!!)
PROJECT=dataflash
Now project parameters are set correctly and the project can be compiled and linked.
> cd board/at91sam9261ek/dataflash
> make
Your image, named dataflash_at91sam9261ek.bin, should be ready now. Simply download the
binary file in DataFlash with SAM-BA Application for example.
3.2.2
Generating NAND Flash Boot
The following example shows how to generate a bootstrap in NAND Flash to launch U-Boot.
The required flags are defined in the board/at91sam9261ek/nandflash/at91sam9261ek.h header
file.
/* Download Settings */
#define IMG_ADDR 0x20000 /* U-Boot Address in NandFlash */
#define IMG_SIZE 0x30000 /* U-Boot size in NandFlash */
#define JUMP_ADDR 0x23F00000 /* U-Boot Link Address in SDRAM */
/* BootStrap Settings */
#undef CFG_DEBUG /* Disable DBGU messages (optional) */
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6277B–ATARM–05-Dec-06
#define CFG_NANDFLASH /* Enable DataFlash Download */
#undef NANDFLASH_SMALL_BLOCKS /*Large Block NandFlash used instead*/
#define CFG_HW_INIT /* Enable Low Level Configuration (PIOs,PMC...)*/
#define CFG_SDRAM /* Enable SDRAM Controller Configuration */
Some project parameters need to be defined in the Makefile. Makefile is located in the
board/at91sam9261ek/nandflash/ project directory.
# NandFlashBoot Configuration for AT91SAM9261EK
# Target name (case sensitive!!!)
TARGET=AT91SAM9261
# Board name (case sensitive!!!)
BOARD=at91sam9261ek
# Link Address and Top_of_Memory
LINK_ADDR=0x300000
# Stack pointer
TOP_OF_MEMORY=0x328000
# Name of current directory (case sensitive!!!)
PROJECT=nandflash
Now the project parameters are set correctly and the project can be compiled and linked.
> cd board/at91sam9261ek/nandflash
> make
Your image, named nandflash_at91sam9261ek.bin, should be ready now. Simply download the
binary file in NANDFlash with SAM-BA Application for example.
3.3
AT91SAM9263 Initialization
The following operations are performed during AT91SAM9263 hardware initialization:
• Disable Watchdog
• Configure PLLA
• Switch MCK to PLLA/2
• Configure PLLB
• Configure PIOs
• Configure Matrix (only when using SDRAMC)
3.3.1
Generating DataFlashBoot
The following example shows how to generate a bootstrap in DataFlash to launch U-Boot.
The required flags are defined in the board/at91sam9263ek/dataflash/at91sam9263ek.h header
file.
/* Download Settings */
18
Application Note
6277B–ATARM–05-Dec-06
Application Note
#define IMG_ADDR 0x8000 /* U-Boot Address in DataFlash */
#define IMG_SIZE 0x30000 /* U-Boot size in DataFlash */
#define JUMP_ADDR 0x23F00000 /* U-Boot Link Address in SDRAM */
/* BootStrap Settings */
#undef CFG_DEBUG /* Disable DBGU messages (optional) */
#define CFG_DATAFLASH /* Enable DataFlash Download */
#define CFG_HW_INIT /* Enable Low Level Configuration (PIOs,PMC...)*/
#define CFG_SDRAM /* Enable SDRAM Controller Configuration */
Some project parameters need to be defined in the Makefile. Makefile is located in the
board/at91sam9263ek/dataflash/ project directory.
# DataFlashBoot Configuration for AT91SAM9263EK
# Target name (case sensitive!!!)
TARGET=AT91SAM9263
# Board name (case sensitive!!!)
BOARD=at91sam9263ek
# Link Address and Top_of_Memory
LINK_ADDR=0x300000
# Stack pointer
TOP_OF_MEMORY=0x314000
# Name of current directory (case sensitive!!!)
PROJECT=dataflash
Now the project parameters are set correctly and the project can be compiled and linked.
> cd board/at91sam9263ek/dataflash
> make
Your image, named dataflash_at91sam9263ek.bin, should be ready now. Simply download the
binary file in DataFlash with SAM-BA Application for example.
4. AT91Bootstrap GNU Project
4.1
4.1.1
Compiling an AT91Bootstrap Project
GNU ARM Toolchain
AT91Bootstrap is compiled with a GNU ARM Toolchain (Code Sourcery, GNU ARM, etc.)
Once your toolchain is installed, install AT91Bootstrap in a directory and cd into it.
4.1.2
Make Command
To compile an AT91Bootstrap project:
1. Go into the board directory.
2. Select your board by going into the corresponding board directory.
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6277B–ATARM–05-Dec-06
3. Select your project by going into the corresponding project directory.
4. Configure your project (Makefile and header file).
5. Type make.
Example:
To compile a NANDFlash boot project for AT91SAM9260-EK board, type the following
commands:
> cd board/at91sam9260ek/nandflash
> make
4.2
Adding a New Board to an AT91Bootstrap Project
To add a new board to the AT91Bootstrap project:
• Copy the board directory which is the most similar to your board, e.g. if your board is based
on a AT91SAM9261 part:
cd board
cp -r at91sam9261ek/ my_board/
• Rename board-specific files.
cd my_board
mv at91sam9261ek.c my_board.c
mv “project“/at91sam9261ek.h “project“/my_board.h
• Edit corresponding “project“ Makefile and modify BOARD variable accordingly.
BOARD=my_board
PROJECT=“project“
• Make your modifications and compile the project.
4.3
Adding a New Project to a Board
To add a new project to the AT91Bootstrap:
• Copy the board directory which is the most similar to your board.
cd board/my_board
mkdir new_project
• Copy a Makefile and my_board.h header file.
cp dataflash/* new_project/.
• Edit corresponding “new_project“ Makefile and modify PROJECT variable accordingly.
PROJECT=new_project
4.4
Adding a New Driver to an AT91Bootstrap Project
To add a new driver to the AT91Bootstrap project:
• Add the new driver in the driver directory. Move the pieces of code which are product or
board dependent into the board/your_board/ directory.
• If necessary, add an include file with the same driver name in the include directory.
• Use pre-processor instructions to insert your new feature into the AT91Bootstrap project.
• Add new driver file into project Makefile.
20
Application Note
6277B–ATARM–05-Dec-06
Application Note
5. Revision History
Table 5-1.
Document Ref.
Comments
6277A
First issue.
6277B
Added Section 3.3 ”AT91SAM9263 Initialization” on page 18.
Change Request
Ref.
21
6277B–ATARM–05-Dec-06
22
Application Note
6277B–ATARM–05-Dec-06
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