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tools/bootloader: Use PL011 UART on all RPi models
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Before the Mini UART was used on RPi 1-4, which depends on the core
clock, which varies with the ARM CPU clock. There have been problems
with setting the clock divider before, which should be fixed with using
the PL011 UART. Further modifications:

* Set RxD to pull-up and TxD to pull-none on RPi 1-4
* Use ARM system timer for go delay on RPi 1-4
* Convert ARM address to bus address for mailbox access on all models
* Slightly increase delay before mailbox access

See: #501
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@rsta2
rsta2 committed Dec 12, 2024
1 parent 7fe9b37 commit d16821d
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Showing 2 changed files with 42 additions and 67 deletions.
1 change: 1 addition & 0 deletions tools/bootloader/BCM2711.h
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Original file line number Diff line number Diff line change
@@ -1 +1,2 @@
#define PBASE 0xFE000000
#define LBASE 0xFF800000 // local peripherals
108 changes: 41 additions & 67 deletions tools/bootloader/periph.c
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Original file line number Diff line number Diff line change
Expand Up @@ -20,35 +20,22 @@ extern void dummy ( unsigned int );

#ifndef RPI5

#define ARM_TIMER_CTL (PBASE+0x0000B408)
#define ARM_TIMER_CNT (PBASE+0x0000B420)
#define ARM_SYSTIMER_CLO (PBASE + 0x3004)

#define GPFSEL1 (PBASE+0x00200004)
#define GPSET0 (PBASE+0x0020001C)
#define GPCLR0 (PBASE+0x00200028)
#define GPPUD (PBASE+0x00200094)
#define GPPUDCLK0 (PBASE+0x00200098)

#define AUX_ENABLES (PBASE+0x00215004)
#define AUX_MU_IO_REG (PBASE+0x00215040)
#define AUX_MU_IER_REG (PBASE+0x00215044)
#define AUX_MU_IIR_REG (PBASE+0x00215048)
#define AUX_MU_LCR_REG (PBASE+0x0021504C)
#define AUX_MU_MCR_REG (PBASE+0x00215050)
#define AUX_MU_LSR_REG (PBASE+0x00215054)
#define AUX_MU_MSR_REG (PBASE+0x00215058)
#define AUX_MU_SCRATCH (PBASE+0x0021505C)
#define AUX_MU_CNTL_REG (PBASE+0x00215060)
#define AUX_MU_STAT_REG (PBASE+0x00215064)
#define AUX_MU_BAUD_REG (PBASE+0x00215068)

//GPIO14 TXD0 and TXD1
//GPIO15 RXD0 and RXD1
#define ARM_UART0_BASE (PBASE + 0x201000)

#else

#define ARM_UART0_BASE (PBASE + 0x1001000)

#endif

#define ARM_UART0_DR (ARM_UART0_BASE + 0x00)
#define ARM_UART0_FR (ARM_UART0_BASE + 0x18)
#define ARM_UART0_IBRD (ARM_UART0_BASE + 0x24)
Expand All @@ -61,6 +48,11 @@ extern void dummy ( unsigned int );
#define ARM_UART0_MIS (ARM_UART0_BASE + 0x40)
#define ARM_UART0_ICR (ARM_UART0_BASE + 0x44)

//------------------------------------------------------------------------
#ifdef RPI4
#define ARM_GPIO_GPPUPPDN0 (PBASE+0x002000E4)

#define ARM_LOCAL_PRESCALER (LBASE + 0x008)
#endif

//------------------------------------------------------------------------
Expand Down Expand Up @@ -88,71 +80,46 @@ extern void dummy ( unsigned int );
#define PROPTAG_END 0x00000000

#define CLOCK_ID_UART 2
#define CLOCK_ID_CORE 4

unsigned get_clock (unsigned nClockID);
unsigned div (unsigned nDividend, unsigned nDivisor);
//------------------------------------------------------------------------
#ifndef RPI5
unsigned int uart_lcr ( void )
{
return(GET32(AUX_MU_LSR_REG));
return(GET32(ARM_UART0_LCRH));
}
#endif
//------------------------------------------------------------------------
unsigned int uart_recv ( void )
{
#ifndef RPI5
while(1)
{
if(GET32(AUX_MU_LSR_REG)&0x01) break;
}
return(GET32(AUX_MU_IO_REG)&0xFF);
#else
while(1)
{
if(!(GET32(ARM_UART0_FR)&0x10)) break;
}
return(GET32(ARM_UART0_DR)&0xFF);
#endif
}
//------------------------------------------------------------------------
unsigned int uart_check ( void )
{
#ifndef RPI5
if(GET32(AUX_MU_LSR_REG)&0x01) return(1);
#else
if(!(GET32(ARM_UART0_FR)&0x10)) return(1);
#endif
return(0);
}
//------------------------------------------------------------------------
void uart_send ( unsigned int c )
{
#ifndef RPI5
while(1)
{
if(GET32(AUX_MU_LSR_REG)&0x20) break;
}
PUT32(AUX_MU_IO_REG,c);
#else
while(1)
{
if(!(GET32(ARM_UART0_FR)&0x20)) break;
}
PUT32(ARM_UART0_DR,c);
#endif
}
//------------------------------------------------------------------------
#ifndef RPI5
void uart_flush ( void )
{
while(1)
{
if((GET32(AUX_MU_LSR_REG)&0x100)==0) break;
if((GET32(ARM_UART0_FR)&0x08)==0) break;
}
}
#endif
//------------------------------------------------------------------------
void hexstrings ( unsigned int d )
{
Expand Down Expand Up @@ -184,27 +151,31 @@ void uart_init ( void )
#ifndef RPI5
unsigned int ra;

PUT32(AUX_ENABLES,1);
PUT32(AUX_MU_IER_REG,0);
PUT32(AUX_MU_CNTL_REG,0);
PUT32(AUX_MU_LCR_REG,3);
PUT32(AUX_MU_MCR_REG,0);
PUT32(AUX_MU_IER_REG,0);
PUT32(AUX_MU_IIR_REG,0xC6);
PUT32(AUX_MU_BAUD_REG,div(get_clock(CLOCK_ID_CORE)/8 + DEFAULTBAUD/2, DEFAULTBAUD) - 1);
ra=GET32(GPFSEL1);
ra&=~(7<<12); //gpio14
ra|=2<<12; //alt5
ra|=4<<12; //alt0
ra&=~(7<<15); //gpio15
ra|=2<<15; //alt5
ra|=4<<15; //alt0
PUT32(GPFSEL1,ra);
PUT32(GPPUD,0);
#ifndef RPI4
PUT32(GPPUD,0); // no pull
for(ra=0;ra<150;ra++) dummy(ra);
PUT32(GPPUDCLK0,(1<<14)|(1<<15));
PUT32(GPPUDCLK0,1<<14);
for(ra=0;ra<150;ra++) dummy(ra);
PUT32(GPPUDCLK0,0);
PUT32(GPPUD,2); // pull up
for(ra=0;ra<150;ra++) dummy(ra);
PUT32(GPPUDCLK0,1<<15);
for(ra=0;ra<150;ra++) dummy(ra);
PUT32(GPPUDCLK0,0);
PUT32(AUX_MU_CNTL_REG,3);
#else
ra=GET32(ARM_GPIO_GPPUPPDN0);
ra &= ~(3 << (14 * 2)); // no pull
ra &= ~(3 << (15 * 2));
ra |= 1 << (15 * 2); // pull up
PUT32(ARM_GPIO_GPPUPPDN0, ra);
#endif
#endif
unsigned nBaudrate = DEFAULTBAUD;
unsigned nClockRate = get_clock(CLOCK_ID_UART);
unsigned nBaud16 = nBaudrate * 16;
Expand All @@ -218,23 +189,19 @@ void uart_init ( void )
PUT32(ARM_UART0_FBRD, nFractDiv);
PUT32(ARM_UART0_LCRH, (1 << 4) | (3 << 5));
PUT32(ARM_UART0_CR, (1 << 0) | (1 << 8) | (1 << 9));
#endif
}
//------------------------------------------------------------------------
void timer_init ( void )
{
#ifndef RPI5
//0xF9+1 = 250
//250MHz/250 = 1MHz
PUT32(ARM_TIMER_CTL,0x00F90000);
PUT32(ARM_TIMER_CTL,0x00F90200);
#if defined(RPI4) && AARCH == 32
PUT32(ARM_LOCAL_PRESCALER, 39768216U); // 1 MHz clock
#endif
}
//-------------------------------------------------------------------------
unsigned int timer_tick ( void )
{
#ifndef RPI5
return(GET32(ARM_TIMER_CNT));
return(GET32(ARM_SYSTIMER_CLO));
#else
asm volatile ("isb" ::: "memory");

Expand All @@ -249,8 +216,10 @@ unsigned int timer_tick ( void )
//-------------------------------------------------------------------------
unsigned mbox_writeread (unsigned nData)
{
#ifdef RPI5
#if defined(RPI2) || defined(RPI4) || defined(RPI5) || AARCH == 64
nData |= 0xC0000000U; // convert to bus address
#else
nData |= 0x40000000U;
#endif

while (GET32 (MAILBOX1_STATUS) & MAILBOX_STATUS_FULL)
Expand Down Expand Up @@ -278,7 +247,7 @@ unsigned mbox_writeread (unsigned nData)
unsigned get_clock (unsigned nClockID)
{
// does not work without a short delay with newer firmware on RPi 1
for (volatile unsigned i = 0; i < 10000; i++);
for (volatile unsigned i = 0; i < 100000; i++);

unsigned proptag[] __attribute__ ((aligned (16))) =
{
Expand Down Expand Up @@ -313,7 +282,12 @@ unsigned get_clock (unsigned nClockID)

mbox_writeread ((unsigned) (unsigned long) &proptag_measured);

return proptag_measured[6];
if (proptag[6] != 0)
{
return proptag[6];
}

return nClockID == CLOCK_ID_UART ? 48000000U : 0; // default value
}
//-------------------------------------------------------------------------
unsigned div (unsigned nDividend, unsigned nDivisor)
Expand Down

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