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qemu/hw/ssi/imx_spi.c
Jean-Christophe Dubois 556899fc19 hw/ssi/imx_spi.c: Remove MSGDATA register support 
From the documentation it is not clear what this SPI register is about.

Moreover, neither linux driver nor xvisor driver are using this SPI register.

For now we just remove it and issue a log on register write access.

Signed-off-by: Jean-Christophe Dubois <jcd@tribudubois.net>
Message-id: 20170107122047.26300-1-jcd@tribudubois.net
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2017-01-09 11:50:23 +00:00

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/*
* IMX SPI Controller
*
* Copyright (c) 2016 Jean-Christophe Dubois <jcd@tribudubois.net>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "hw/ssi/imx_spi.h"
#include "sysemu/sysemu.h"
#include "qemu/log.h"
#ifndef DEBUG_IMX_SPI
#define DEBUG_IMX_SPI 0
#endif
#define DPRINTF(fmt, args...) \
do { \
if (DEBUG_IMX_SPI) { \
fprintf(stderr, "[%s]%s: " fmt , TYPE_IMX_SPI, \
__func__, ##args); \
} \
} while (0)
static const char *imx_spi_reg_name(uint32_t reg)
{
static char unknown[20];
switch (reg) {
case ECSPI_RXDATA:
return "ECSPI_RXDATA";
case ECSPI_TXDATA:
return "ECSPI_TXDATA";
case ECSPI_CONREG:
return "ECSPI_CONREG";
case ECSPI_CONFIGREG:
return "ECSPI_CONFIGREG";
case ECSPI_INTREG:
return "ECSPI_INTREG";
case ECSPI_DMAREG:
return "ECSPI_DMAREG";
case ECSPI_STATREG:
return "ECSPI_STATREG";
case ECSPI_PERIODREG:
return "ECSPI_PERIODREG";
case ECSPI_TESTREG:
return "ECSPI_TESTREG";
case ECSPI_MSGDATA:
return "ECSPI_MSGDATA";
default:
sprintf(unknown, "%d ?", reg);
return unknown;
}
}
static const VMStateDescription vmstate_imx_spi = {
.name = TYPE_IMX_SPI,
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_FIFO32(tx_fifo, IMXSPIState),
VMSTATE_FIFO32(rx_fifo, IMXSPIState),
VMSTATE_INT16(burst_length, IMXSPIState),
VMSTATE_UINT32_ARRAY(regs, IMXSPIState, ECSPI_MAX),
VMSTATE_END_OF_LIST()
},
};
static void imx_spi_txfifo_reset(IMXSPIState *s)
{
fifo32_reset(&s->tx_fifo);
s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TE;
s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_TF;
}
static void imx_spi_rxfifo_reset(IMXSPIState *s)
{
fifo32_reset(&s->rx_fifo);
s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RR;
s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RF;
s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RO;
}
static void imx_spi_update_irq(IMXSPIState *s)
{
int level;
if (fifo32_is_empty(&s->rx_fifo)) {
s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RR;
} else {
s->regs[ECSPI_STATREG] |= ECSPI_STATREG_RR;
}
if (fifo32_is_full(&s->rx_fifo)) {
s->regs[ECSPI_STATREG] |= ECSPI_STATREG_RF;
} else {
s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RF;
}
if (fifo32_is_empty(&s->tx_fifo)) {
s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TE;
} else {
s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_TE;
}
if (fifo32_is_full(&s->tx_fifo)) {
s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TF;
} else {
s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_TF;
}
level = s->regs[ECSPI_STATREG] & s->regs[ECSPI_INTREG] ? 1 : 0;
qemu_set_irq(s->irq, level);
DPRINTF("IRQ level is %d\n", level);
}
static uint8_t imx_spi_selected_channel(IMXSPIState *s)
{
return EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_CHANNEL_SELECT);
}
static uint32_t imx_spi_burst_length(IMXSPIState *s)
{
return EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_BURST_LENGTH) + 1;
}
static bool imx_spi_is_enabled(IMXSPIState *s)
{
return s->regs[ECSPI_CONREG] & ECSPI_CONREG_EN;
}
static bool imx_spi_channel_is_master(IMXSPIState *s)
{
uint8_t mode = EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_CHANNEL_MODE);
return (mode & (1 << imx_spi_selected_channel(s))) ? true : false;
}
static bool imx_spi_is_multiple_master_burst(IMXSPIState *s)
{
uint8_t wave = EXTRACT(s->regs[ECSPI_CONFIGREG], ECSPI_CONFIGREG_SS_CTL);
return imx_spi_channel_is_master(s) &&
!(s->regs[ECSPI_CONREG] & ECSPI_CONREG_SMC) &&
((wave & (1 << imx_spi_selected_channel(s))) ? true : false);
}
static void imx_spi_flush_txfifo(IMXSPIState *s)
{
uint32_t tx;
uint32_t rx;
DPRINTF("Begin: TX Fifo Size = %d, RX Fifo Size = %d\n",
fifo32_num_used(&s->tx_fifo), fifo32_num_used(&s->rx_fifo));
while (!fifo32_is_empty(&s->tx_fifo)) {
int tx_burst = 0;
int index = 0;
if (s->burst_length <= 0) {
s->burst_length = imx_spi_burst_length(s);
DPRINTF("Burst length = %d\n", s->burst_length);
if (imx_spi_is_multiple_master_burst(s)) {
s->regs[ECSPI_CONREG] |= ECSPI_CONREG_XCH;
}
}
tx = fifo32_pop(&s->tx_fifo);
DPRINTF("data tx:0x%08x\n", tx);
tx_burst = MIN(s->burst_length, 32);
rx = 0;
while (tx_burst) {
uint8_t byte = tx & 0xff;
DPRINTF("writing 0x%02x\n", (uint32_t)byte);
/* We need to write one byte at a time */
byte = ssi_transfer(s->bus, byte);
DPRINTF("0x%02x read\n", (uint32_t)byte);
tx = tx >> 8;
rx |= (byte << (index * 8));
/* Remove 8 bits from the actual burst */
tx_burst -= 8;
s->burst_length -= 8;
index++;
}
DPRINTF("data rx:0x%08x\n", rx);
if (fifo32_is_full(&s->rx_fifo)) {
s->regs[ECSPI_STATREG] |= ECSPI_STATREG_RO;
} else {
fifo32_push(&s->rx_fifo, (uint8_t)rx);
}
if (s->burst_length <= 0) {
s->regs[ECSPI_CONREG] &= ~ECSPI_CONREG_XCH;
if (!imx_spi_is_multiple_master_burst(s)) {
s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TC;
break;
}
}
}
if (fifo32_is_empty(&s->tx_fifo)) {
s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TC;
}
/* TODO: We should also use TDR and RDR bits */
DPRINTF("End: TX Fifo Size = %d, RX Fifo Size = %d\n",
fifo32_num_used(&s->tx_fifo), fifo32_num_used(&s->rx_fifo));
}
static void imx_spi_reset(DeviceState *dev)
{
IMXSPIState *s = IMX_SPI(dev);
DPRINTF("\n");
memset(s->regs, 0, sizeof(s->regs));
s->regs[ECSPI_STATREG] = 0x00000003;
imx_spi_rxfifo_reset(s);
imx_spi_txfifo_reset(s);
imx_spi_update_irq(s);
s->burst_length = 0;
}
static uint64_t imx_spi_read(void *opaque, hwaddr offset, unsigned size)
{
uint32_t value = 0;
IMXSPIState *s = opaque;
uint32_t index = offset >> 2;
if (index >= ECSPI_MAX) {
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%"
HWADDR_PRIx "\n", TYPE_IMX_SPI, __func__, offset);
return 0;
}
switch (index) {
case ECSPI_RXDATA:
if (!imx_spi_is_enabled(s)) {
value = 0;
} else if (fifo32_is_empty(&s->rx_fifo)) {
/* value is undefined */
value = 0xdeadbeef;
} else {
/* read from the RX FIFO */
value = fifo32_pop(&s->rx_fifo);
}
break;
case ECSPI_TXDATA:
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read from TX FIFO\n",
TYPE_IMX_SPI, __func__);
/* Reading from TXDATA gives 0 */
break;
case ECSPI_MSGDATA:
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read from MSG FIFO\n",
TYPE_IMX_SPI, __func__);
/* Reading from MSGDATA gives 0 */
break;
default:
value = s->regs[index];
break;
}
DPRINTF("reg[%s] => 0x%" PRIx32 "\n", imx_spi_reg_name(index), value);
imx_spi_update_irq(s);
return (uint64_t)value;
}
static void imx_spi_write(void *opaque, hwaddr offset, uint64_t value,
unsigned size)
{
IMXSPIState *s = opaque;
uint32_t index = offset >> 2;
uint32_t change_mask;
if (index >= ECSPI_MAX) {
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%"
HWADDR_PRIx "\n", TYPE_IMX_SPI, __func__, offset);
return;
}
DPRINTF("reg[%s] <= 0x%" PRIx32 "\n", imx_spi_reg_name(index),
(uint32_t)value);
change_mask = s->regs[index] ^ value;
switch (index) {
case ECSPI_RXDATA:
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to write to RX FIFO\n",
TYPE_IMX_SPI, __func__);
break;
case ECSPI_TXDATA:
if (!imx_spi_is_enabled(s)) {
/* Ignore writes if device is disabled */
break;
} else if (fifo32_is_full(&s->tx_fifo)) {
/* Ignore writes if queue is full */
break;
}
fifo32_push(&s->tx_fifo, (uint32_t)value);
if (imx_spi_channel_is_master(s) &&
(s->regs[ECSPI_CONREG] & ECSPI_CONREG_SMC)) {
/*
* Start emitting if current channel is master and SMC bit is
* set.
*/
imx_spi_flush_txfifo(s);
}
break;
case ECSPI_STATREG:
/* the RO and TC bits are write-one-to-clear */
value &= ECSPI_STATREG_RO | ECSPI_STATREG_TC;
s->regs[ECSPI_STATREG] &= ~value;
break;
case ECSPI_CONREG:
s->regs[ECSPI_CONREG] = value;
if (!imx_spi_is_enabled(s)) {
/* device is disabled, so this is a reset */
imx_spi_reset(DEVICE(s));
return;
}
if (imx_spi_channel_is_master(s)) {
int i;
/* We are in master mode */
for (i = 0; i < 4; i++) {
qemu_set_irq(s->cs_lines[i],
i == imx_spi_selected_channel(s) ? 0 : 1);
}
if ((value & change_mask & ECSPI_CONREG_SMC) &&
!fifo32_is_empty(&s->tx_fifo)) {
/* SMC bit is set and TX FIFO has some slots filled in */
imx_spi_flush_txfifo(s);
} else if ((value & change_mask & ECSPI_CONREG_XCH) &&
!(value & ECSPI_CONREG_SMC)) {
/* This is a request to start emitting */
imx_spi_flush_txfifo(s);
}
}
break;
case ECSPI_MSGDATA:
/* it is not clear from the spec what MSGDATA is for */
/* Anyway it is not used by Linux driver */
/* So for now we just ignore it */
qemu_log_mask(LOG_UNIMP,
"[%s]%s: Trying to write to MSGDATA, ignoring\n",
TYPE_IMX_SPI, __func__);
break;
default:
s->regs[index] = value;
break;
}
imx_spi_update_irq(s);
}
static const struct MemoryRegionOps imx_spi_ops = {
.read = imx_spi_read,
.write = imx_spi_write,
.endianness = DEVICE_NATIVE_ENDIAN,
.valid = {
/*
* Our device would not work correctly if the guest was doing
* unaligned access. This might not be a limitation on the real
* device but in practice there is no reason for a guest to access
* this device unaligned.
*/
.min_access_size = 4,
.max_access_size = 4,
.unaligned = false,
},
};
static void imx_spi_realize(DeviceState *dev, Error **errp)
{
IMXSPIState *s = IMX_SPI(dev);
int i;
s->bus = ssi_create_bus(dev, "spi");
memory_region_init_io(&s->iomem, OBJECT(dev), &imx_spi_ops, s,
TYPE_IMX_SPI, 0x1000);
sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq);
ssi_auto_connect_slaves(dev, s->cs_lines, s->bus);
for (i = 0; i < 4; ++i) {
sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->cs_lines[i]);
}
s->burst_length = 0;
fifo32_create(&s->tx_fifo, ECSPI_FIFO_SIZE);
fifo32_create(&s->rx_fifo, ECSPI_FIFO_SIZE);
}
static void imx_spi_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->realize = imx_spi_realize;
dc->vmsd = &vmstate_imx_spi;
dc->reset = imx_spi_reset;
dc->desc = "i.MX SPI Controller";
}
static const TypeInfo imx_spi_info = {
.name = TYPE_IMX_SPI,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(IMXSPIState),
.class_init = imx_spi_class_init,
};
static void imx_spi_register_types(void)
{
type_register_static(&imx_spi_info);
}
type_init(imx_spi_register_types)
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