312 lines
8.0 KiB
C
312 lines
8.0 KiB
C
/*
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* Arm PrimeCell PL022 Synchronous Serial Port
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*
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* Copyright (c) 2007 CodeSourcery.
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* Written by Paul Brook
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*
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* This code is licenced under the GPL.
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*/
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#include "sysbus.h"
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#include "ssi.h"
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#include "primecell.h"
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//#define DEBUG_PL022 1
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#ifdef DEBUG_PL022
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#define DPRINTF(fmt, ...) \
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do { printf("pl022: " fmt , ## __VA_ARGS__); } while (0)
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#define BADF(fmt, ...) \
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do { fprintf(stderr, "pl022: error: " fmt , ## __VA_ARGS__); exit(1);} while (0)
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#else
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#define DPRINTF(fmt, ...) do {} while(0)
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#define BADF(fmt, ...) \
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do { fprintf(stderr, "pl022: error: " fmt , ## __VA_ARGS__);} while (0)
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#endif
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#define PL022_CR1_LBM 0x01
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#define PL022_CR1_SSE 0x02
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#define PL022_CR1_MS 0x04
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#define PL022_CR1_SDO 0x08
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#define PL022_SR_TFE 0x01
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#define PL022_SR_TNF 0x02
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#define PL022_SR_RNE 0x04
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#define PL022_SR_RFF 0x08
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#define PL022_SR_BSY 0x10
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#define PL022_INT_ROR 0x01
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#define PL022_INT_RT 0x04
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#define PL022_INT_RX 0x04
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#define PL022_INT_TX 0x08
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typedef struct {
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SysBusDevice busdev;
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uint32_t cr0;
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uint32_t cr1;
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uint32_t bitmask;
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uint32_t sr;
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uint32_t cpsr;
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uint32_t is;
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uint32_t im;
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/* The FIFO head points to the next empty entry. */
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int tx_fifo_head;
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int rx_fifo_head;
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int tx_fifo_len;
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int rx_fifo_len;
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uint16_t tx_fifo[8];
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uint16_t rx_fifo[8];
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qemu_irq irq;
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SSIBus *ssi;
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} pl022_state;
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static const unsigned char pl022_id[8] =
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{ 0x22, 0x10, 0x04, 0x00, 0x0d, 0xf0, 0x05, 0xb1 };
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static void pl022_update(pl022_state *s)
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{
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s->sr = 0;
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if (s->tx_fifo_len == 0)
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s->sr |= PL022_SR_TFE;
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if (s->tx_fifo_len != 8)
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s->sr |= PL022_SR_TNF;
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if (s->rx_fifo_len != 0)
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s->sr |= PL022_SR_RNE;
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if (s->rx_fifo_len == 8)
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s->sr |= PL022_SR_RFF;
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if (s->tx_fifo_len)
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s->sr |= PL022_SR_BSY;
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s->is = 0;
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if (s->rx_fifo_len >= 4)
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s->is |= PL022_INT_RX;
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if (s->tx_fifo_len <= 4)
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s->is |= PL022_INT_TX;
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qemu_set_irq(s->irq, (s->is & s->im) != 0);
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}
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static void pl022_xfer(pl022_state *s)
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{
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int i;
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int o;
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int val;
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if ((s->cr1 & PL022_CR1_SSE) == 0) {
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pl022_update(s);
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DPRINTF("Disabled\n");
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return;
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}
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DPRINTF("Maybe xfer %d/%d\n", s->tx_fifo_len, s->rx_fifo_len);
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i = (s->tx_fifo_head - s->tx_fifo_len) & 7;
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o = s->rx_fifo_head;
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/* ??? We do not emulate the line speed.
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This may break some applications. The are two problematic cases:
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(a) A driver feeds data into the TX FIFO until it is full,
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and only then drains the RX FIFO. On real hardware the CPU can
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feed data fast enough that the RX fifo never gets chance to overflow.
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(b) A driver transmits data, deliberately allowing the RX FIFO to
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overflow because it ignores the RX data anyway.
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We choose to support (a) by stalling the transmit engine if it would
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cause the RX FIFO to overflow. In practice much transmit-only code
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falls into (a) because it flushes the RX FIFO to determine when
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the transfer has completed. */
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while (s->tx_fifo_len && s->rx_fifo_len < 8) {
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DPRINTF("xfer\n");
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val = s->tx_fifo[i];
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if (s->cr1 & PL022_CR1_LBM) {
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/* Loopback mode. */
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} else {
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val = ssi_transfer(s->ssi, val);
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}
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s->rx_fifo[o] = val & s->bitmask;
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i = (i + 1) & 7;
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o = (o + 1) & 7;
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s->tx_fifo_len--;
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s->rx_fifo_len++;
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}
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s->rx_fifo_head = o;
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pl022_update(s);
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}
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static uint32_t pl022_read(void *opaque, target_phys_addr_t offset)
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{
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pl022_state *s = (pl022_state *)opaque;
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int val;
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if (offset >= 0xfe0 && offset < 0x1000) {
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return pl022_id[(offset - 0xfe0) >> 2];
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}
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switch (offset) {
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case 0x00: /* CR0 */
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return s->cr0;
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case 0x04: /* CR1 */
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return s->cr1;
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case 0x08: /* DR */
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if (s->rx_fifo_len) {
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val = s->rx_fifo[(s->rx_fifo_head - s->rx_fifo_len) & 7];
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DPRINTF("RX %02x\n", val);
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s->rx_fifo_len--;
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pl022_xfer(s);
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} else {
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val = 0;
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}
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return val;
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case 0x0c: /* SR */
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return s->sr;
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case 0x10: /* CPSR */
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return s->cpsr;
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case 0x14: /* IMSC */
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return s->im;
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case 0x18: /* RIS */
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return s->is;
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case 0x1c: /* MIS */
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return s->im & s->is;
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case 0x20: /* DMACR */
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/* Not implemented. */
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return 0;
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default:
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hw_error("pl022_read: Bad offset %x\n", (int)offset);
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return 0;
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}
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}
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static void pl022_write(void *opaque, target_phys_addr_t offset,
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uint32_t value)
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{
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pl022_state *s = (pl022_state *)opaque;
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switch (offset) {
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case 0x00: /* CR0 */
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s->cr0 = value;
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/* Clock rate and format are ignored. */
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s->bitmask = (1 << ((value & 15) + 1)) - 1;
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break;
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case 0x04: /* CR1 */
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s->cr1 = value;
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if ((s->cr1 & (PL022_CR1_MS | PL022_CR1_SSE))
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== (PL022_CR1_MS | PL022_CR1_SSE)) {
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BADF("SPI slave mode not implemented\n");
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}
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pl022_xfer(s);
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break;
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case 0x08: /* DR */
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if (s->tx_fifo_len < 8) {
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DPRINTF("TX %02x\n", value);
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s->tx_fifo[s->tx_fifo_head] = value & s->bitmask;
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s->tx_fifo_head = (s->tx_fifo_head + 1) & 7;
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s->tx_fifo_len++;
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pl022_xfer(s);
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}
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break;
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case 0x10: /* CPSR */
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/* Prescaler. Ignored. */
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s->cpsr = value & 0xff;
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break;
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case 0x14: /* IMSC */
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s->im = value;
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pl022_update(s);
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break;
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case 0x20: /* DMACR */
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if (value) {
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hw_error("pl022: DMA not implemented\n");
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}
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break;
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default:
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hw_error("pl022_write: Bad offset %x\n", (int)offset);
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}
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}
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static void pl022_reset(pl022_state *s)
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{
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s->rx_fifo_len = 0;
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s->tx_fifo_len = 0;
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s->im = 0;
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s->is = PL022_INT_TX;
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s->sr = PL022_SR_TFE | PL022_SR_TNF;
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}
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static CPUReadMemoryFunc *pl022_readfn[] = {
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pl022_read,
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pl022_read,
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pl022_read
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};
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static CPUWriteMemoryFunc *pl022_writefn[] = {
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pl022_write,
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pl022_write,
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pl022_write
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};
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static void pl022_save(QEMUFile *f, void *opaque)
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{
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pl022_state *s = (pl022_state *)opaque;
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int i;
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qemu_put_be32(f, s->cr0);
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qemu_put_be32(f, s->cr1);
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qemu_put_be32(f, s->bitmask);
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qemu_put_be32(f, s->sr);
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qemu_put_be32(f, s->cpsr);
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qemu_put_be32(f, s->is);
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qemu_put_be32(f, s->im);
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qemu_put_be32(f, s->tx_fifo_head);
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qemu_put_be32(f, s->rx_fifo_head);
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qemu_put_be32(f, s->tx_fifo_len);
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qemu_put_be32(f, s->rx_fifo_len);
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for (i = 0; i < 8; i++) {
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qemu_put_be16(f, s->tx_fifo[i]);
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qemu_put_be16(f, s->rx_fifo[i]);
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}
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}
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static int pl022_load(QEMUFile *f, void *opaque, int version_id)
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{
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pl022_state *s = (pl022_state *)opaque;
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int i;
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if (version_id != 1)
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return -EINVAL;
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s->cr0 = qemu_get_be32(f);
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s->cr1 = qemu_get_be32(f);
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s->bitmask = qemu_get_be32(f);
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s->sr = qemu_get_be32(f);
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s->cpsr = qemu_get_be32(f);
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s->is = qemu_get_be32(f);
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s->im = qemu_get_be32(f);
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s->tx_fifo_head = qemu_get_be32(f);
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s->rx_fifo_head = qemu_get_be32(f);
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s->tx_fifo_len = qemu_get_be32(f);
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s->rx_fifo_len = qemu_get_be32(f);
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for (i = 0; i < 8; i++) {
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s->tx_fifo[i] = qemu_get_be16(f);
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s->rx_fifo[i] = qemu_get_be16(f);
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}
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return 0;
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}
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static void pl022_init(SysBusDevice *dev)
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{
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pl022_state *s = FROM_SYSBUS(pl022_state, dev);
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int iomemtype;
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iomemtype = cpu_register_io_memory(0, pl022_readfn,
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pl022_writefn, s);
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sysbus_init_mmio(dev, 0x1000, iomemtype);
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sysbus_init_irq(dev, &s->irq);
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s->ssi = ssi_create_bus();
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qdev_attach_child_bus(&dev->qdev, "ssi", s->ssi);
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pl022_reset(s);
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register_savevm("pl022_ssp", -1, 1, pl022_save, pl022_load, s);
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}
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static void pl022_register_devices(void)
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{
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sysbus_register_dev("pl022", sizeof(pl022_state), pl022_init);
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}
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device_init(pl022_register_devices)
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