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qemu-e2k/hw/omap_i2c.c

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/*
* TI OMAP on-chip I2C controller. Only "new I2C" mode supported.
*
* Copyright (C) 2007 Andrzej Zaborowski <balrog@zabor.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include "vl.h"
struct omap_i2c_s {
target_phys_addr_t base;
qemu_irq irq;
qemu_irq drq[2];
i2c_slave slave;
i2c_bus *bus;
uint8_t mask;
uint16_t stat;
uint16_t dma;
uint16_t count;
int count_cur;
uint32_t fifo;
int rxlen;
int txlen;
uint16_t control;
uint16_t addr[2];
uint8_t divider;
uint8_t times[2];
uint16_t test;
};
static void omap_i2c_interrupts_update(struct omap_i2c_s *s)
{
qemu_set_irq(s->irq, s->stat & s->mask);
if ((s->dma >> 15) & 1) /* RDMA_EN */
qemu_set_irq(s->drq[0], (s->stat >> 3) & 1); /* RRDY */
if ((s->dma >> 7) & 1) /* XDMA_EN */
qemu_set_irq(s->drq[1], (s->stat >> 4) & 1); /* XRDY */
}
/* These are only stubs now. */
static void omap_i2c_event(i2c_slave *i2c, enum i2c_event event)
{
struct omap_i2c_s *s = (struct omap_i2c_s *) i2c;
if ((~s->control >> 15) & 1) /* I2C_EN */
return;
switch (event) {
case I2C_START_SEND:
case I2C_START_RECV:
s->stat |= 1 << 9; /* AAS */
break;
case I2C_FINISH:
s->stat |= 1 << 2; /* ARDY */
break;
case I2C_NACK:
s->stat |= 1 << 1; /* NACK */
break;
}
omap_i2c_interrupts_update(s);
}
static int omap_i2c_rx(i2c_slave *i2c)
{
struct omap_i2c_s *s = (struct omap_i2c_s *) i2c;
uint8_t ret = 0;
if ((~s->control >> 15) & 1) /* I2C_EN */
return -1;
if (s->txlen)
ret = s->fifo >> ((-- s->txlen) << 3) & 0xff;
else
s->stat |= 1 << 10; /* XUDF */
s->stat |= 1 << 4; /* XRDY */
omap_i2c_interrupts_update(s);
return ret;
}
static int omap_i2c_tx(i2c_slave *i2c, uint8_t data)
{
struct omap_i2c_s *s = (struct omap_i2c_s *) i2c;
if ((~s->control >> 15) & 1) /* I2C_EN */
return 1;
if (s->rxlen < 4)
s->fifo |= data << ((s->rxlen ++) << 3);
else
s->stat |= 1 << 11; /* ROVR */
s->stat |= 1 << 3; /* RRDY */
omap_i2c_interrupts_update(s);
return 1;
}
static void omap_i2c_fifo_run(struct omap_i2c_s *s)
{
int ack = 1;
if (!i2c_bus_busy(s->bus))
return;
if ((s->control >> 2) & 1) { /* RM */
if ((s->control >> 1) & 1) { /* STP */
i2c_end_transfer(s->bus);
s->control &= ~(1 << 1); /* STP */
s->count_cur = s->count;
} else if ((s->control >> 9) & 1) { /* TRX */
while (ack && s->txlen)
ack = (i2c_send(s->bus,
(s->fifo >> ((-- s->txlen) << 3)) &
0xff) >= 0);
s->stat |= 1 << 4; /* XRDY */
} else {
while (s->rxlen < 4)
s->fifo |= i2c_recv(s->bus) << ((s->rxlen ++) << 3);
s->stat |= 1 << 3; /* RRDY */
}
} else {
if ((s->control >> 9) & 1) { /* TRX */
while (ack && s->count_cur && s->txlen) {
ack = (i2c_send(s->bus,
(s->fifo >> ((-- s->txlen) << 3)) &
0xff) >= 0);
s->count_cur --;
}
if (ack && s->count_cur)
s->stat |= 1 << 4; /* XRDY */
if (!s->count_cur) {
s->stat |= 1 << 2; /* ARDY */
s->control &= ~(1 << 10); /* MST */
}
} else {
while (s->count_cur && s->rxlen < 4) {
s->fifo |= i2c_recv(s->bus) << ((s->rxlen ++) << 3);
s->count_cur --;
}
if (s->rxlen)
s->stat |= 1 << 3; /* RRDY */
}
if (!s->count_cur) {
if ((s->control >> 1) & 1) { /* STP */
i2c_end_transfer(s->bus);
s->control &= ~(1 << 1); /* STP */
s->count_cur = s->count;
} else {
s->stat |= 1 << 2; /* ARDY */
s->control &= ~(1 << 10); /* MST */
}
}
}
s->stat |= (!ack) << 1; /* NACK */
if (!ack)
s->control &= ~(1 << 1); /* STP */
}
void omap_i2c_reset(struct omap_i2c_s *s)
{
s->mask = 0;
s->stat = 0;
s->dma = 0;
s->count = 0;
s->count_cur = 0;
s->fifo = 0;
s->rxlen = 0;
s->txlen = 0;
s->control = 0;
s->addr[0] = 0;
s->addr[1] = 0;
s->divider = 0;
s->times[0] = 0;
s->times[1] = 0;
s->test = 0;
}
static uint32_t omap_i2c_read(void *opaque, target_phys_addr_t addr)
{
struct omap_i2c_s *s = (struct omap_i2c_s *) opaque;
int offset = addr - s->base;
uint16_t ret;
switch (offset) {
case 0x00: /* I2C_REV */
/* TODO: set a value greater or equal to real hardware */
return 0x11; /* REV */
case 0x04: /* I2C_IE */
return s->mask;
case 0x08: /* I2C_STAT */
return s->stat | (i2c_bus_busy(s->bus) << 12);
case 0x0c: /* I2C_IV */
ret = ffs(s->stat & s->mask);
if (ret)
s->stat ^= 1 << (ret - 1);
omap_i2c_interrupts_update(s);
return ret;
case 0x14: /* I2C_BUF */
return s->dma;
case 0x18: /* I2C_CNT */
return s->count_cur; /* DCOUNT */
case 0x1c: /* I2C_DATA */
ret = 0;
if (s->control & (1 << 14)) { /* BE */
ret |= ((s->fifo >> 0) & 0xff) << 8;
ret |= ((s->fifo >> 8) & 0xff) << 0;
} else {
ret |= ((s->fifo >> 8) & 0xff) << 8;
ret |= ((s->fifo >> 0) & 0xff) << 0;
}
if (s->rxlen == 1) {
s->stat |= 1 << 15; /* SBD */
s->rxlen = 0;
} else if (s->rxlen > 1) {
if (s->rxlen > 2)
s->fifo >>= 16;
s->rxlen -= 2;
} else
/* XXX: remote access (qualifier) error - what's that? */;
if (!s->rxlen) {
s->stat |= ~(1 << 3); /* RRDY */
if (((s->control >> 10) & 1) && /* MST */
((~s->control >> 9) & 1)) { /* TRX */
s->stat |= 1 << 2; /* ARDY */
s->control &= ~(1 << 10); /* MST */
}
}
s->stat &= ~(1 << 11); /* ROVR */
omap_i2c_fifo_run(s);
omap_i2c_interrupts_update(s);
return ret;
case 0x24: /* I2C_CON */
return s->control;
case 0x28: /* I2C_OA */
return s->addr[0];
case 0x2c: /* I2C_SA */
return s->addr[1];
case 0x30: /* I2C_PSC */
return s->divider;
case 0x34: /* I2C_SCLL */
return s->times[0];
case 0x38: /* I2C_SCLH */
return s->times[1];
case 0x3c: /* I2C_SYSTEST */
if (s->test & (1 << 15)) { /* ST_EN */
s->test ^= 0xa;
return s->test;
} else
return s->test & ~0x300f;
}
OMAP_BAD_REG(addr);
return 0;
}
static void omap_i2c_write(void *opaque, target_phys_addr_t addr,
uint32_t value)
{
struct omap_i2c_s *s = (struct omap_i2c_s *) opaque;
int offset = addr - s->base;
int nack;
switch (offset) {
case 0x00: /* I2C_REV */
case 0x08: /* I2C_STAT */
case 0x0c: /* I2C_IV */
OMAP_BAD_REG(addr);
return;
case 0x04: /* I2C_IE */
s->mask = value & 0x1f;
break;
case 0x14: /* I2C_BUF */
s->dma = value & 0x8080;
if (value & (1 << 15)) /* RDMA_EN */
s->mask &= ~(1 << 3); /* RRDY_IE */
if (value & (1 << 7)) /* XDMA_EN */
s->mask &= ~(1 << 4); /* XRDY_IE */
break;
case 0x18: /* I2C_CNT */
s->count = value; /* DCOUNT */
break;
case 0x1c: /* I2C_DATA */
if (s->txlen > 2) {
/* XXX: remote access (qualifier) error - what's that? */
break;
}
s->fifo <<= 16;
s->txlen += 2;
if (s->control & (1 << 14)) { /* BE */
s->fifo |= ((value >> 8) & 0xff) << 8;
s->fifo |= ((value >> 0) & 0xff) << 0;
} else {
s->fifo |= ((value >> 0) & 0xff) << 8;
s->fifo |= ((value >> 8) & 0xff) << 0;
}
s->stat &= ~(1 << 10); /* XUDF */
if (s->txlen > 2)
s->stat &= ~(1 << 4); /* XRDY */
omap_i2c_fifo_run(s);
omap_i2c_interrupts_update(s);
break;
case 0x24: /* I2C_CON */
s->control = value & 0xcf07;
if (~value & (1 << 15)) { /* I2C_EN */
omap_i2c_reset(s);
break;
}
if (~value & (1 << 10)) { /* MST */
printf("%s: I^2C slave mode not supported\n", __FUNCTION__);
break;
}
if (value & (1 << 9)) { /* XA */
printf("%s: 10-bit addressing mode not supported\n", __FUNCTION__);
break;
}
if (value & (1 << 0)) { /* STT */
nack = !!i2c_start_transfer(s->bus, s->addr[1], /* SA */
(~value >> 9) & 1); /* TRX */
s->stat |= nack << 1; /* NACK */
s->control &= ~(1 << 0); /* STT */
if (nack)
s->control &= ~(1 << 1); /* STP */
else
omap_i2c_fifo_run(s);
omap_i2c_interrupts_update(s);
}
break;
case 0x28: /* I2C_OA */
s->addr[0] = value & 0x3ff;
i2c_set_slave_address(&s->slave, value & 0x7f);
break;
case 0x2c: /* I2C_SA */
s->addr[1] = value & 0x3ff;
break;
case 0x30: /* I2C_PSC */
s->divider = value;
break;
case 0x34: /* I2C_SCLL */
s->times[0] = value;
break;
case 0x38: /* I2C_SCLH */
s->times[1] = value;
break;
case 0x3c: /* I2C_SYSTEST */
s->test = value & 0xf00f;
if (value & (1 << 15)) /* ST_EN */
printf("%s: System Test not supported\n", __FUNCTION__);
break;
default:
OMAP_BAD_REG(addr);
return;
}
}
static CPUReadMemoryFunc *omap_i2c_readfn[] = {
omap_badwidth_read16,
omap_i2c_read,
omap_badwidth_read16,
};
static CPUWriteMemoryFunc *omap_i2c_writefn[] = {
omap_badwidth_write16,
omap_i2c_write,
omap_i2c_write, /* TODO: Only the last fifo write can be 8 bit. */
};
struct omap_i2c_s *omap_i2c_init(target_phys_addr_t base,
qemu_irq irq, qemu_irq *dma, omap_clk clk)
{
int iomemtype;
struct omap_i2c_s *s = (struct omap_i2c_s *)
qemu_mallocz(sizeof(struct omap_i2c_s));
s->base = base;
s->irq = irq;
s->drq[0] = dma[0];
s->drq[1] = dma[1];
s->slave.event = omap_i2c_event;
s->slave.recv = omap_i2c_rx;
s->slave.send = omap_i2c_tx;
s->bus = i2c_init_bus();
omap_i2c_reset(s);
iomemtype = cpu_register_io_memory(0, omap_i2c_readfn,
omap_i2c_writefn, s);
cpu_register_physical_memory(s->base, 0x800, iomemtype);
return s;
}
i2c_bus *omap_i2c_bus(struct omap_i2c_s *s)
{
return s->bus;
}
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