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xilinx_spips: Fix striping behaviour

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The QSPI controller was using byte-wide stripes when striping across
the two flashes in dual parallel mode. The real hardware however uses
individual bit striping. QEMU misbehaves in the (corner) case where
data is written/read in dual-parallel mode and read/written back in
single mode.

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: 718a61df1bf746ec06f6da44d12f8317af7b08ce.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 17:17:43 +01:00 committed by Peter Maydell
parent 2133a5f6b8
commit 9151da25a7
1 changed files with 63 additions and 21 deletions
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84
hw/ssi/xilinx_spips.c
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@ -273,35 +273,77 @@ static void xilinx_spips_reset(DeviceState *d)
xilinx_spips_update_cs_lines(s);
}
/* N way (num) in place bit striper. Lay out row wise bits (LSB to MSB)
* column wise (from element 0 to N-1). num is the length of x, and dir
* reverses the direction of the transform. Best illustrated by example:
* Each digit in the below array is a single bit (num == 3):
*
* {{ 76543210, } ----- stripe (dir == false) -----> {{ FCheb630, }
* { hgfedcba, } { GDAfc741, }
* { HGFEDCBA, }} <---- upstripe (dir == true) ----- { HEBgda52, }}
*/
static inline void stripe8(uint8_t *x, int num, bool dir)
{
uint8_t r[num];
memset(r, 0, sizeof(uint8_t) * num);
int idx[2] = {0, 0};
int bit[2] = {0, 0};
int d = dir;
for (idx[0] = 0; idx[0] < num; ++idx[0]) {
for (bit[0] = 0; bit[0] < 8; ++bit[0]) {
r[idx[d]] |= x[idx[!d]] & 1 << bit[!d] ? 1 << bit[d] : 0;
idx[1] = (idx[1] + 1) % num;
if (!idx[1]) {
bit[1]++;
}
}
}
memcpy(x, r, sizeof(uint8_t) * num);
}
static void xilinx_spips_flush_txfifo(XilinxSPIPS *s)
{
for (;;) {
int i;
uint8_t rx;
uint8_t tx = 0;
uint8_t tx_rx[num_effective_busses(s)];
if (fifo8_is_empty(&s->tx_fifo)) {
if (!(s->regs[R_LQSPI_CFG] & LQSPI_CFG_LQ_MODE)) {
s->regs[R_INTR_STATUS] |= IXR_TX_FIFO_UNDERFLOW;
}
xilinx_spips_update_ixr(s);
return;
} else if (s->snoop_state == SNOOP_STRIPING) {
for (i = 0; i < num_effective_busses(s); ++i) {
tx_rx[i] = fifo8_pop(&s->tx_fifo);
}
stripe8(tx_rx, num_effective_busses(s), false);
} else {
tx = fifo8_pop(&s->tx_fifo);
for (i = 0; i < num_effective_busses(s); ++i) {
tx_rx[i] = tx;
}
}
for (i = 0; i < num_effective_busses(s); ++i) {
if (!i || s->snoop_state == SNOOP_STRIPING) {
if (fifo8_is_empty(&s->tx_fifo)) {
if (!(s->regs[R_LQSPI_CFG] & LQSPI_CFG_LQ_MODE)) {
s->regs[R_INTR_STATUS] |= IXR_TX_FIFO_UNDERFLOW;
}
xilinx_spips_update_ixr(s);
return;
} else {
tx = fifo8_pop(&s->tx_fifo);
}
}
rx = ssi_transfer(s->spi[i], (uint32_t)tx);
DB_PRINT("tx = %02x rx = %02x\n", tx, rx);
if (!i || s->snoop_state == SNOOP_STRIPING) {
if (fifo8_is_full(&s->rx_fifo)) {
s->regs[R_INTR_STATUS] |= IXR_RX_FIFO_OVERFLOW;
DB_PRINT("rx FIFO overflow");
} else {
fifo8_push(&s->rx_fifo, (uint8_t)rx);
}
DB_PRINT("tx = %02x\n", tx_rx[i]);
tx_rx[i] = ssi_transfer(s->spi[i], (uint32_t)tx_rx[i]);
DB_PRINT("rx = %02x\n", tx_rx[i]);
}
if (fifo8_is_full(&s->rx_fifo)) {
s->regs[R_INTR_STATUS] |= IXR_RX_FIFO_OVERFLOW;
DB_PRINT("rx FIFO overflow");
} else if (s->snoop_state == SNOOP_STRIPING) {
stripe8(tx_rx, num_effective_busses(s), true);
for (i = 0; i < num_effective_busses(s); ++i) {
fifo8_push(&s->rx_fifo, (uint8_t)tx_rx[i]);
}
} else {
fifo8_push(&s->rx_fifo, (uint8_t)tx_rx[0]);
}
switch (s->snoop_state) {