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/*
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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 "hw.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, args...) \
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do { printf("pl022: " fmt , ##args); } while (0) |
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#define BADF(fmt, args...) \
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do { fprintf(stderr, "pl022: error: " fmt , ##args); exit(1);} while (0) |
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#else
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#define DPRINTF(fmt, args...) do {} while(0) |
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#define BADF(fmt, args...) \
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do { fprintf(stderr, "pl022: error: " fmt , ##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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uint32_t base; |
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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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int (*xfer_cb)(void *, int); |
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void *opaque;
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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 if (s->xfer_cb) { |
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val = s->xfer_cb(s->opaque, val); |
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} else {
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val = 0;
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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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offset -= s->base; |
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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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cpu_abort (cpu_single_env, "pl022_read: Bad offset %x\n",
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(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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offset -= s->base; |
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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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cpu_abort (cpu_single_env, "pl022: DMA not implemented\n");
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break;
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default:
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cpu_abort (cpu_single_env, "pl022_write: Bad offset %x\n",
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(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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void pl022_init(uint32_t base, qemu_irq irq, int (*xfer_cb)(void *, int), |
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void * opaque)
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{ |
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int iomemtype;
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pl022_state *s; |
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s = (pl022_state *)qemu_mallocz(sizeof(pl022_state));
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iomemtype = cpu_register_io_memory(0, pl022_readfn,
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pl022_writefn, s); |
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cpu_register_physical_memory(base, 0x00001000, iomemtype);
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s->base = base; |
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s->irq = irq; |
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s->xfer_cb = xfer_cb; |
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s->opaque = opaque; |
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pl022_reset(s); |
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/* ??? Save/restore. */
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} |
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