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xilinx_spips: Implement automatic CS

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Implement the automatic CS control feature. If the MANUAL_CS bit is
cleared then the chip select stay de-asserted as long as the tx FIFO
is empty.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Message-id: 1d67383adc42761af715a93f161344b9284dfc9a.1369117359.git.peter.crosthwaite@xilinx.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Peter Crosthwaite 2013-06-03 17:17:42 +01:00 committed by Peter Maydell
parent e100f3be0c
commit c4f08ffe13
1 changed files with 14 additions and 4 deletions
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18
hw/ssi/xilinx_spips.c
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@ -190,6 +190,12 @@ static inline int num_effective_busses(XilinxSPIPS *s)
s->regs[R_LQSPI_CFG] & LQSPI_CFG_TWO_MEM) ? s->num_busses : 1;
}
static inline bool xilinx_spips_cs_is_set(XilinxSPIPS *s, int i, int field)
{
return ~field & (1 << i) && (s->regs[R_CONFIG] & MANUAL_CS
|| !fifo8_is_empty(&s->tx_fifo));
}
static void xilinx_spips_update_cs_lines(XilinxSPIPS *s)
{
int i, j;
@ -202,14 +208,15 @@ static void xilinx_spips_update_cs_lines(XilinxSPIPS *s)
int cs_to_set = (j * s->num_cs + i + upage) %
(s->num_cs * s->num_busses);
if (~field & (1 << i) && !found) {
if (xilinx_spips_cs_is_set(s, i, field) && !found) {
DB_PRINT("selecting slave %d\n", i);
qemu_set_irq(s->cs_lines[cs_to_set], 0);
} else {
DB_PRINT("deselecting slave %d\n", i);
qemu_set_irq(s->cs_lines[cs_to_set], 1);
}
}
if (~field & (1 << i)) {
if (xilinx_spips_cs_is_set(s, i, field)) {
found = true;
}
}
@ -451,12 +458,13 @@ static void xilinx_spips_write(void *opaque, hwaddr addr,
}
s->regs[addr] = (s->regs[addr] & ~mask) | (value & mask);
no_reg_update:
xilinx_spips_update_cs_lines(s);
if ((man_start_com && s->regs[R_CONFIG] & MAN_START_EN) ||
(fifo8_is_empty(&s->tx_fifo) && s->regs[R_CONFIG] & MAN_START_EN)) {
xilinx_spips_flush_txfifo(s);
}
xilinx_spips_update_ixr(s);
xilinx_spips_update_cs_lines(s);
xilinx_spips_update_ixr(s);
}
static const MemoryRegionOps spips_ops = {
@ -510,7 +518,7 @@ lqspi_read(void *opaque, hwaddr addr, unsigned int size)
fifo8_reset(&s->rx_fifo);
s->regs[R_CONFIG] &= ~CS;
s->regs[R_CONFIG] |= (~(1 << slave) << CS_SHIFT) & CS;
s->regs[R_CONFIG] |= ((~(1 << slave) << CS_SHIFT) & CS) | MANUAL_CS;
xilinx_spips_update_cs_lines(s);
/* instruction */
@ -534,6 +542,7 @@ lqspi_read(void *opaque, hwaddr addr, unsigned int size)
DB_PRINT("pushing dummy byte\n");
fifo8_push(&s->tx_fifo, 0);
}
xilinx_spips_update_cs_lines(s);
xilinx_spips_flush_txfifo(s);
fifo8_reset(&s->rx_fifo);
@ -545,6 +554,7 @@ lqspi_read(void *opaque, hwaddr addr, unsigned int size)
rx_data_bytes(s, &q->lqspi_buf[cache_entry], 4);
cache_entry++;
}
xilinx_spips_update_cs_lines(s);
s->regs[R_CONFIG] |= CS;
xilinx_spips_update_cs_lines(s);