Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20231221031652.119827-56-richard.henderson@linaro.org>
		
			
				
	
	
		
			317 lines
		
	
	
		
			8.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			317 lines
		
	
	
		
			8.8 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 licensed under the GPL.
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 */
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#include "qemu/osdep.h"
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#include "hw/sysbus.h"
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#include "migration/vmstate.h"
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#include "hw/irq.h"
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#include "hw/ssi/pl022.h"
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#include "hw/ssi/ssi.h"
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#include "qemu/log.h"
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#include "qemu/module.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  0x02
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#define PL022_INT_RX  0x04
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#define PL022_INT_TX  0x08
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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(PL022State *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(PL022State *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 uint64_t pl022_read(void *opaque, hwaddr offset,
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                           unsigned size)
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{
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    PL022State *s = (PL022State *)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 0x24: /* DMACR */
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        /* Not implemented.  */
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        return 0;
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    default:
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        qemu_log_mask(LOG_GUEST_ERROR,
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                      "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, hwaddr offset,
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                        uint64_t value, unsigned size)
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{
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    PL022State *s = (PL022State *)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 peripheral 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", (unsigned)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: /* ICR */
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        /*
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         * write-1-to-clear: bit 0 clears ROR, bit 1 clears RT;
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         * RX and TX interrupts cannot be cleared this way.
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         */
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        value &= PL022_INT_ROR | PL022_INT_RT;
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        s->is &= ~value;
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        break;
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    case 0x24: /* DMACR */
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        if (value) {
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            qemu_log_mask(LOG_UNIMP, "pl022: DMA not implemented\n");
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        }
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        break;
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    default:
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        qemu_log_mask(LOG_GUEST_ERROR,
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                      "pl022_write: Bad offset %x\n", (int)offset);
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    }
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}
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static void pl022_reset(DeviceState *dev)
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{
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    PL022State *s = PL022(dev);
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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 const MemoryRegionOps pl022_ops = {
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    .read = pl022_read,
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    .write = pl022_write,
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    .endianness = DEVICE_NATIVE_ENDIAN,
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};
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static int pl022_post_load(void *opaque, int version_id)
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{
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    PL022State *s = opaque;
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    if (s->tx_fifo_head < 0 ||
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        s->tx_fifo_head >= ARRAY_SIZE(s->tx_fifo) ||
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        s->rx_fifo_head < 0 ||
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        s->rx_fifo_head >= ARRAY_SIZE(s->rx_fifo)) {
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        return -1;
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    }
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    return 0;
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}
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static const VMStateDescription vmstate_pl022 = {
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    .name = "pl022_ssp",
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    .version_id = 1,
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    .minimum_version_id = 1,
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    .post_load = pl022_post_load,
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    .fields = (const VMStateField[]) {
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        VMSTATE_UINT32(cr0, PL022State),
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        VMSTATE_UINT32(cr1, PL022State),
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        VMSTATE_UINT32(bitmask, PL022State),
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        VMSTATE_UINT32(sr, PL022State),
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        VMSTATE_UINT32(cpsr, PL022State),
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        VMSTATE_UINT32(is, PL022State),
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        VMSTATE_UINT32(im, PL022State),
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        VMSTATE_INT32(tx_fifo_head, PL022State),
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        VMSTATE_INT32(rx_fifo_head, PL022State),
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        VMSTATE_INT32(tx_fifo_len, PL022State),
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        VMSTATE_INT32(rx_fifo_len, PL022State),
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        VMSTATE_UINT16(tx_fifo[0], PL022State),
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        VMSTATE_UINT16(rx_fifo[0], PL022State),
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        VMSTATE_UINT16(tx_fifo[1], PL022State),
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        VMSTATE_UINT16(rx_fifo[1], PL022State),
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        VMSTATE_UINT16(tx_fifo[2], PL022State),
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        VMSTATE_UINT16(rx_fifo[2], PL022State),
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        VMSTATE_UINT16(tx_fifo[3], PL022State),
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        VMSTATE_UINT16(rx_fifo[3], PL022State),
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        VMSTATE_UINT16(tx_fifo[4], PL022State),
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        VMSTATE_UINT16(rx_fifo[4], PL022State),
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        VMSTATE_UINT16(tx_fifo[5], PL022State),
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        VMSTATE_UINT16(rx_fifo[5], PL022State),
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        VMSTATE_UINT16(tx_fifo[6], PL022State),
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        VMSTATE_UINT16(rx_fifo[6], PL022State),
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        VMSTATE_UINT16(tx_fifo[7], PL022State),
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        VMSTATE_UINT16(rx_fifo[7], PL022State),
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        VMSTATE_END_OF_LIST()
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    }
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};
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static void pl022_realize(DeviceState *dev, Error **errp)
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{
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    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
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    PL022State *s = PL022(dev);
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    memory_region_init_io(&s->iomem, OBJECT(s), &pl022_ops, s, "pl022", 0x1000);
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    sysbus_init_mmio(sbd, &s->iomem);
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    sysbus_init_irq(sbd, &s->irq);
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    s->ssi = ssi_create_bus(dev, "ssi");
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}
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static void pl022_class_init(ObjectClass *klass, void *data)
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{
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    DeviceClass *dc = DEVICE_CLASS(klass);
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    dc->reset = pl022_reset;
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    dc->vmsd = &vmstate_pl022;
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    dc->realize = pl022_realize;
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}
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static const TypeInfo pl022_info = {
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    .name          = TYPE_PL022,
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    .parent        = TYPE_SYS_BUS_DEVICE,
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    .instance_size = sizeof(PL022State),
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    .class_init    = pl022_class_init,
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};
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static void pl022_register_types(void)
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{
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    type_register_static(&pl022_info);
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}
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type_init(pl022_register_types)
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