ref: 1216c06c3bdf3f3fb953ec96de99e026ef318360
dir: /sys/src/9/bcm/uartmini.c/
/*
* bcm2835 mini uart (UART1)
*/
#include "u.h"
#include "../port/lib.h"
#include "../port/error.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#define GPIOREGS (VIRTIO+0x200000)
#define AUXREGS (VIRTIO+0x215000)
#define OkLed 16
#define TxPin 14
#define RxPin 15
/* GPIO regs */
enum {
Fsel0 = 0x00>>2,
FuncMask= 0x7,
Input = 0x0,
Output = 0x1,
Alt0 = 0x4,
Alt1 = 0x5,
Alt2 = 0x6,
Alt3 = 0x7,
Alt4 = 0x3,
Alt5 = 0x2,
Set0 = 0x1c>>2,
Clr0 = 0x28>>2,
Lev0 = 0x34>>2,
PUD = 0x94>>2,
Off = 0x0,
Pulldown= 0x1,
Pullup = 0x2,
PUDclk0 = 0x98>>2,
PUDclk1 = 0x9c>>2,
};
/* AUX regs */
enum {
Irq = 0x00>>2,
UartIrq = 1<<0,
Enables = 0x04>>2,
UartEn = 1<<0,
MuIo = 0x40>>2,
MuIer = 0x44>>2,
RxIen = 1<<0,
TxIen = 1<<1,
MuIir = 0x48>>2,
MuLcr = 0x4c>>2,
Bitsmask= 3<<0,
Bits7 = 2<<0,
Bits8 = 3<<0,
MuMcr = 0x50>>2,
RtsN = 1<<1,
MuLsr = 0x54>>2,
TxDone = 1<<6,
TxRdy = 1<<5,
RxRdy = 1<<0,
MuCntl = 0x60>>2,
CtsFlow = 1<<3,
TxEn = 1<<1,
RxEn = 1<<0,
MuBaud = 0x68>>2,
};
extern PhysUart miniphysuart;
static Uart miniuart = {
.regs = (u32int*)AUXREGS,
.name = "uart0",
.freq = 250000000,
.phys = &miniphysuart,
};
void
gpiosel(uint pin, int func)
{
u32int *gp, *fsel;
int off;
gp = (u32int*)GPIOREGS;
fsel = &gp[Fsel0 + pin/10];
off = (pin % 10) * 3;
*fsel = (*fsel & ~(FuncMask << off)) | func << off;
}
void
gpiopulloff(uint pin)
{
u32int *gp, *reg;
u32int mask;
gp = (u32int*)GPIOREGS;
reg = &gp[PUDclk0 + pin/32];
mask = 1 << (pin % 32);
gp[PUD] = Off;
microdelay(1);
*reg = mask;
microdelay(1);
*reg = 0;
}
void
gpioout(uint pin, int set)
{
u32int *gp;
int v;
gp = (u32int*)GPIOREGS;
v = set? Set0: Clr0;
gp[v + pin/32] = 1 << (pin % 32);
}
int
gpioin(uint pin)
{
u32int *gp;
gp = (u32int*)GPIOREGS;
return (gp[Lev0 + pin/32] & (1 << (pin % 32))) != 0;
}
static void
interrupt(Ureg*, void *arg)
{
Uart *uart;
u32int *ap;
uart = arg;
ap = (u32int*)uart->regs;
coherence();
if(0 && (ap[Irq] & UartIrq) == 0)
return;
if(ap[MuLsr] & TxRdy)
uartkick(uart);
if(ap[MuLsr] & RxRdy){
do{
uartrecv(uart, ap[MuIo] & 0xFF);
}while(ap[MuLsr] & RxRdy);
}
coherence();
}
static Uart*
pnp(void)
{
return &miniuart;
}
static void
enable(Uart *uart, int ie)
{
u32int *ap;
ap = (u32int*)uart->regs;
delay(10);
gpiosel(TxPin, Alt5);
gpiosel(RxPin, Alt5);
gpiopulloff(TxPin);
gpiopulloff(RxPin);
ap[Enables] |= UartEn;
ap[MuIir] = 6;
ap[MuCntl] = TxEn|RxEn;
if(ie){
intrenable(IRQaux, interrupt, uart, 0, "uart");
ap[MuIer] = RxIen|TxIen;
}else
ap[MuIer] = 0;
}
static void
disable(Uart *uart)
{
u32int *ap;
ap = (u32int*)uart->regs;
ap[MuCntl] = 0;
ap[MuIer] = 0;
}
static void
kick(Uart *uart)
{
u32int *ap;
ap = (u32int*)uart->regs;
if(uart->blocked)
return;
coherence();
while(ap[MuLsr] & TxRdy){
if(uart->op >= uart->oe && uartstageoutput(uart) == 0)
break;
ap[MuIo] = *(uart->op++);
}
if(ap[MuLsr] & TxDone)
ap[MuIer] &= ~TxIen;
else
ap[MuIer] |= TxIen;
coherence();
}
/* TODO */
static void
dobreak(Uart *uart, int ms)
{
USED(uart, ms);
}
static int
baud(Uart *uart, int n)
{
u32int *ap;
ap = (u32int*)uart->regs;
if(uart->freq == 0 || n <= 0)
return -1;
ap[MuBaud] = (uart->freq + 4*n - 1) / (8 * n) - 1;
uart->baud = n;
return 0;
}
static int
bits(Uart *uart, int n)
{
u32int *ap;
int set;
ap = (u32int*)uart->regs;
switch(n){
case 7:
set = Bits7;
break;
case 8:
set = Bits8;
break;
default:
return -1;
}
ap[MuLcr] = (ap[MuLcr] & ~Bitsmask) | set;
uart->bits = n;
return 0;
}
static int
stop(Uart *uart, int n)
{
if(n != 1)
return -1;
uart->stop = n;
return 0;
}
static int
parity(Uart *uart, int n)
{
if(n != 'n')
return -1;
uart->parity = n;
return 0;
}
/*
* cts/rts flow control
* need to bring signals to gpio pins before enabling this
*/
static void
modemctl(Uart *uart, int on)
{
u32int *ap;
ap = (u32int*)uart->regs;
if(on)
ap[MuCntl] |= CtsFlow;
else
ap[MuCntl] &= ~CtsFlow;
uart->modem = on;
}
static void
rts(Uart *uart, int on)
{
u32int *ap;
ap = (u32int*)uart->regs;
if(on)
ap[MuMcr] &= ~RtsN;
else
ap[MuMcr] |= RtsN;
}
static long
status(Uart *uart, void *buf, long n, long offset)
{
char *p;
p = malloc(READSTR);
if(p == nil)
error(Enomem);
snprint(p, READSTR,
"b%d\n"
"dev(%d) type(%d) framing(%d) overruns(%d) "
"berr(%d) serr(%d)\n",
uart->baud,
uart->dev,
uart->type,
uart->ferr,
uart->oerr,
uart->berr,
uart->serr
);
n = readstr(offset, buf, n, p);
free(p);
return n;
}
static void
donothing(Uart*, int)
{
}
void
putc(Uart*, int c)
{
u32int *ap;
ap = (u32int*)AUXREGS;
while((ap[MuLsr] & TxRdy) == 0)
;
ap[MuIo] = c;
while((ap[MuLsr] & TxRdy) == 0)
;
}
int
getc(Uart*)
{
u32int *ap;
ap = (u32int*)AUXREGS;
while((ap[MuLsr] & RxRdy) == 0)
;
return ap[MuIo] & 0xFF;
}
void
uartconsinit(void)
{
Uart *uart;
int n;
char *p, *cmd;
if((p = getconf("console")) == nil)
return;
n = strtoul(p, &cmd, 0);
if(p == cmd)
return;
switch(n){
default:
return;
case 0:
uart = &miniuart;
break;
}
uartctl(uart, "b9600 l8 pn s1");
if(*cmd != '\0')
uartctl(uart, cmd);
if(!uart->enabled)
(*uart->phys->enable)(uart, 0);
consuart = uart;
uart->console = 1;
}
PhysUart miniphysuart = {
.name = "miniuart",
.pnp = pnp,
.enable = enable,
.disable = disable,
.kick = kick,
.dobreak = dobreak,
.baud = baud,
.bits = bits,
.stop = stop,
.parity = parity,
.modemctl = donothing,
.rts = rts,
.dtr = donothing,
.status = status,
.fifo = donothing,
.getc = getc,
.putc = putc,
};
void
okay(int on)
{
static int first;
if(!first++)
gpiosel(OkLed, Output);
gpioout(OkLed, !on);
}