Merge remote-tracking branch 'spi/topic/mpc512x' into spi-next
This commit is contained in:
Mark Brown
commit
95e40cc528
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@ -21,7 +21,6 @@
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#include <linux/interrupt.h>
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#include <linux/of_address.h>
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#include <linux/of_platform.h>
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#include <linux/workqueue.h>
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#include <linux/completion.h>
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#include <linux/io.h>
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#include <linux/delay.h>
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@ -33,24 +32,15 @@
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struct mpc512x_psc_spi {
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void (*cs_control)(struct spi_device *spi, bool on);
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u32 sysclk;
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/* driver internal data */
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struct mpc52xx_psc __iomem *psc;
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struct mpc512x_psc_fifo __iomem *fifo;
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unsigned int irq;
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u8 bits_per_word;
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u8 busy;
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u32 mclk;
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u8 eofbyte;
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struct workqueue_struct *workqueue;
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struct work_struct work;
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struct list_head queue;
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spinlock_t lock; /* Message queue lock */
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struct completion done;
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struct completion txisrdone;
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};
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/* controller state */
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@ -136,145 +126,223 @@ static int mpc512x_psc_spi_transfer_rxtx(struct spi_device *spi,
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struct spi_transfer *t)
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{
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struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
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struct mpc52xx_psc __iomem *psc = mps->psc;
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struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
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size_t len = t->len;
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size_t tx_len = t->len;
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size_t rx_len = t->len;
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u8 *tx_buf = (u8 *)t->tx_buf;
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u8 *rx_buf = (u8 *)t->rx_buf;
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if (!tx_buf && !rx_buf && t->len)
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return -EINVAL;
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while (rx_len || tx_len) {
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size_t txcount;
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u8 data;
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size_t fifosz;
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size_t rxcount;
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int rxtries;
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/*
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* send the TX bytes in as large a chunk as possible
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* but neither exceed the TX nor the RX FIFOs
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*/
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fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->txsz));
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txcount = min(fifosz, tx_len);
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fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->rxsz));
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fifosz -= in_be32(&fifo->rxcnt) + 1;
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txcount = min(fifosz, txcount);
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if (txcount) {
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/* fill the TX FIFO */
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while (txcount-- > 0) {
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data = tx_buf ? *tx_buf++ : 0;
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if (tx_len == EOFBYTE && t->cs_change)
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setbits32(&fifo->txcmd,
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MPC512x_PSC_FIFO_EOF);
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out_8(&fifo->txdata_8, data);
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tx_len--;
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}
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/* have the ISR trigger when the TX FIFO is empty */
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INIT_COMPLETION(mps->txisrdone);
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out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY);
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out_be32(&fifo->tximr, MPC512x_PSC_FIFO_EMPTY);
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wait_for_completion(&mps->txisrdone);
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}
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/*
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* consume as much RX data as the FIFO holds, while we
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* iterate over the transfer's TX data length
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*
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* only insist in draining all the remaining RX bytes
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* when the TX bytes were exhausted (that's at the very
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* end of this transfer, not when still iterating over
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* the transfer's chunks)
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*/
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rxtries = 50;
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do {
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/*
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* grab whatever was in the FIFO when we started
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* looking, don't bother fetching what was added to
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* the FIFO while we read from it -- we'll return
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* here eventually and prefer sending out remaining
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* TX data
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*/
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fifosz = in_be32(&fifo->rxcnt);
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rxcount = min(fifosz, rx_len);
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while (rxcount-- > 0) {
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data = in_8(&fifo->rxdata_8);
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if (rx_buf)
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*rx_buf++ = data;
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rx_len--;
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}
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/*
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* come back later if there still is TX data to send,
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* bail out of the RX drain loop if all of the TX data
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* was sent and all of the RX data was received (i.e.
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* when the transmission has completed)
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*/
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if (tx_len)
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break;
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if (!rx_len)
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break;
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/*
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* TX data transmission has completed while RX data
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* is still pending -- that's a transient situation
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* which depends on wire speed and specific
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* hardware implementation details (buffering) yet
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* should resolve very quickly
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*
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* just yield for a moment to not hog the CPU for
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* too long when running SPI at low speed
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*
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* the timeout range is rather arbitrary and tries
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* to balance throughput against system load; the
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* chosen values result in a minimal timeout of 50
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* times 10us and thus work at speeds as low as
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* some 20kbps, while the maximum timeout at the
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* transfer's end could be 5ms _if_ nothing else
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* ticks in the system _and_ RX data still wasn't
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* received, which only occurs in situations that
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* are exceptional; removing the unpredictability
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* of the timeout either decreases throughput
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* (longer timeouts), or puts more load on the
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* system (fixed short timeouts) or requires the
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* use of a timeout API instead of a counter and an
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* unknown inner delay
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*/
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usleep_range(10, 100);
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} while (--rxtries > 0);
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if (!tx_len && rx_len && !rxtries) {
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/*
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* not enough RX bytes even after several retries
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* and the resulting rather long timeout?
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*/
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rxcount = in_be32(&fifo->rxcnt);
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dev_warn(&spi->dev,
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"short xfer, missing %zd RX bytes, FIFO level %zd\n",
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rx_len, rxcount);
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}
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/*
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* drain and drop RX data which "should not be there" in
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* the first place, for undisturbed transmission this turns
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* into a NOP (except for the FIFO level fetch)
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*/
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if (!tx_len && !rx_len) {
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while (in_be32(&fifo->rxcnt))
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in_8(&fifo->rxdata_8);
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}
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}
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return 0;
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}
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static int mpc512x_psc_spi_msg_xfer(struct spi_master *master,
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struct spi_message *m)
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{
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struct spi_device *spi;
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unsigned cs_change;
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int status;
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struct spi_transfer *t;
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spi = m->spi;
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cs_change = 1;
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status = 0;
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list_for_each_entry(t, &m->transfers, transfer_list) {
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if (t->bits_per_word || t->speed_hz) {
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status = mpc512x_psc_spi_transfer_setup(spi, t);
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if (status < 0)
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break;
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}
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if (cs_change)
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mpc512x_psc_spi_activate_cs(spi);
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cs_change = t->cs_change;
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status = mpc512x_psc_spi_transfer_rxtx(spi, t);
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if (status)
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break;
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m->actual_length += t->len;
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if (t->delay_usecs)
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udelay(t->delay_usecs);
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if (cs_change)
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mpc512x_psc_spi_deactivate_cs(spi);
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}
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m->status = status;
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m->complete(m->context);
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if (status || !cs_change)
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mpc512x_psc_spi_deactivate_cs(spi);
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mpc512x_psc_spi_transfer_setup(spi, NULL);
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spi_finalize_current_message(master);
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return status;
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}
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static int mpc512x_psc_spi_prep_xfer_hw(struct spi_master *master)
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{
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struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
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struct mpc52xx_psc __iomem *psc = mps->psc;
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dev_dbg(&master->dev, "%s()\n", __func__);
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/* Zero MR2 */
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in_8(&psc->mode);
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out_8(&psc->mode, 0x0);
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/* enable transmiter/receiver */
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/* enable transmitter/receiver */
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out_8(&psc->command, MPC52xx_PSC_TX_ENABLE | MPC52xx_PSC_RX_ENABLE);
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while (len) {
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int count;
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int i;
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u8 data;
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size_t fifosz;
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int rxcount;
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/*
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* The number of bytes that can be sent at a time
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* depends on the fifo size.
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*/
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fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->txsz));
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count = min(fifosz, len);
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for (i = count; i > 0; i--) {
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data = tx_buf ? *tx_buf++ : 0;
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if (len == EOFBYTE && t->cs_change)
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setbits32(&fifo->txcmd, MPC512x_PSC_FIFO_EOF);
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out_8(&fifo->txdata_8, data);
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len--;
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}
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INIT_COMPLETION(mps->done);
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/* interrupt on tx fifo empty */
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out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY);
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out_be32(&fifo->tximr, MPC512x_PSC_FIFO_EMPTY);
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wait_for_completion(&mps->done);
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mdelay(1);
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/* rx fifo should have count bytes in it */
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rxcount = in_be32(&fifo->rxcnt);
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if (rxcount != count)
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mdelay(1);
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rxcount = in_be32(&fifo->rxcnt);
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if (rxcount != count) {
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dev_warn(&spi->dev, "expected %d bytes in rx fifo "
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"but got %d\n", count, rxcount);
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}
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rxcount = min(rxcount, count);
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for (i = rxcount; i > 0; i--) {
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data = in_8(&fifo->rxdata_8);
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if (rx_buf)
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*rx_buf++ = data;
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}
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while (in_be32(&fifo->rxcnt)) {
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in_8(&fifo->rxdata_8);
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}
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}
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/* disable transmiter/receiver and fifo interrupt */
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out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
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out_be32(&fifo->tximr, 0);
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return 0;
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}
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static void mpc512x_psc_spi_work(struct work_struct *work)
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static int mpc512x_psc_spi_unprep_xfer_hw(struct spi_master *master)
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{
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struct mpc512x_psc_spi *mps = container_of(work,
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struct mpc512x_psc_spi,
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work);
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struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
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struct mpc52xx_psc __iomem *psc = mps->psc;
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struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
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spin_lock_irq(&mps->lock);
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mps->busy = 1;
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while (!list_empty(&mps->queue)) {
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struct spi_message *m;
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struct spi_device *spi;
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struct spi_transfer *t = NULL;
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unsigned cs_change;
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int status;
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dev_dbg(&master->dev, "%s()\n", __func__);
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m = container_of(mps->queue.next, struct spi_message, queue);
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list_del_init(&m->queue);
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spin_unlock_irq(&mps->lock);
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/* disable transmitter/receiver and fifo interrupt */
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out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
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out_be32(&fifo->tximr, 0);
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|
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spi = m->spi;
|
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cs_change = 1;
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status = 0;
|
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list_for_each_entry(t, &m->transfers, transfer_list) {
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if (t->bits_per_word || t->speed_hz) {
|
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status = mpc512x_psc_spi_transfer_setup(spi, t);
|
||||
if (status < 0)
|
||||
break;
|
||||
}
|
||||
|
||||
if (cs_change)
|
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mpc512x_psc_spi_activate_cs(spi);
|
||||
cs_change = t->cs_change;
|
||||
|
||||
status = mpc512x_psc_spi_transfer_rxtx(spi, t);
|
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if (status)
|
||||
break;
|
||||
m->actual_length += t->len;
|
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|
||||
if (t->delay_usecs)
|
||||
udelay(t->delay_usecs);
|
||||
|
||||
if (cs_change)
|
||||
mpc512x_psc_spi_deactivate_cs(spi);
|
||||
}
|
||||
|
||||
m->status = status;
|
||||
m->complete(m->context);
|
||||
|
||||
if (status || !cs_change)
|
||||
mpc512x_psc_spi_deactivate_cs(spi);
|
||||
|
||||
mpc512x_psc_spi_transfer_setup(spi, NULL);
|
||||
|
||||
spin_lock_irq(&mps->lock);
|
||||
}
|
||||
mps->busy = 0;
|
||||
spin_unlock_irq(&mps->lock);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int mpc512x_psc_spi_setup(struct spi_device *spi)
|
||||
{
|
||||
struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
|
||||
struct mpc512x_psc_spi_cs *cs = spi->controller_state;
|
||||
unsigned long flags;
|
||||
int ret;
|
||||
|
||||
if (spi->bits_per_word % 8)
|
||||
|
|
@ -303,28 +371,6 @@ static int mpc512x_psc_spi_setup(struct spi_device *spi)
|
|||
cs->bits_per_word = spi->bits_per_word;
|
||||
cs->speed_hz = spi->max_speed_hz;
|
||||
|
||||
spin_lock_irqsave(&mps->lock, flags);
|
||||
if (!mps->busy)
|
||||
mpc512x_psc_spi_deactivate_cs(spi);
|
||||
spin_unlock_irqrestore(&mps->lock, flags);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int mpc512x_psc_spi_transfer(struct spi_device *spi,
|
||||
struct spi_message *m)
|
||||
{
|
||||
struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
|
||||
unsigned long flags;
|
||||
|
||||
m->actual_length = 0;
|
||||
m->status = -EINPROGRESS;
|
||||
|
||||
spin_lock_irqsave(&mps->lock, flags);
|
||||
list_add_tail(&m->queue, &mps->queue);
|
||||
queue_work(mps->workqueue, &mps->work);
|
||||
spin_unlock_irqrestore(&mps->lock, flags);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
|
@ -407,12 +453,12 @@ static irqreturn_t mpc512x_psc_spi_isr(int irq, void *dev_id)
|
|||
struct mpc512x_psc_spi *mps = (struct mpc512x_psc_spi *)dev_id;
|
||||
struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
|
||||
|
||||
/* clear interrupt and wake up the work queue */
|
||||
/* clear interrupt and wake up the rx/tx routine */
|
||||
if (in_be32(&fifo->txisr) &
|
||||
in_be32(&fifo->tximr) & MPC512x_PSC_FIFO_EMPTY) {
|
||||
out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY);
|
||||
out_be32(&fifo->tximr, 0);
|
||||
complete(&mps->done);
|
||||
complete(&mps->txisrdone);
|
||||
return IRQ_HANDLED;
|
||||
}
|
||||
return IRQ_NONE;
|
||||
|
|
@ -444,18 +490,18 @@ static int mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
|
|||
|
||||
if (pdata == NULL) {
|
||||
mps->cs_control = mpc512x_spi_cs_control;
|
||||
mps->sysclk = 0;
|
||||
master->bus_num = bus_num;
|
||||
} else {
|
||||
mps->cs_control = pdata->cs_control;
|
||||
mps->sysclk = pdata->sysclk;
|
||||
master->bus_num = pdata->bus_num;
|
||||
master->num_chipselect = pdata->max_chipselect;
|
||||
}
|
||||
|
||||
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
|
||||
master->setup = mpc512x_psc_spi_setup;
|
||||
master->transfer = mpc512x_psc_spi_transfer;
|
||||
master->prepare_transfer_hardware = mpc512x_psc_spi_prep_xfer_hw;
|
||||
master->transfer_one_message = mpc512x_psc_spi_msg_xfer;
|
||||
master->unprepare_transfer_hardware = mpc512x_psc_spi_unprep_xfer_hw;
|
||||
master->cleanup = mpc512x_psc_spi_cleanup;
|
||||
master->dev.of_node = dev->of_node;
|
||||
|
||||
|
|
@ -473,31 +519,18 @@ static int mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
|
|||
"mpc512x-psc-spi", mps);
|
||||
if (ret)
|
||||
goto free_master;
|
||||
init_completion(&mps->txisrdone);
|
||||
|
||||
ret = mpc512x_psc_spi_port_config(master, mps);
|
||||
if (ret < 0)
|
||||
goto free_irq;
|
||||
|
||||
spin_lock_init(&mps->lock);
|
||||
init_completion(&mps->done);
|
||||
INIT_WORK(&mps->work, mpc512x_psc_spi_work);
|
||||
INIT_LIST_HEAD(&mps->queue);
|
||||
|
||||
mps->workqueue =
|
||||
create_singlethread_workqueue(dev_name(master->dev.parent));
|
||||
if (mps->workqueue == NULL) {
|
||||
ret = -EBUSY;
|
||||
goto free_irq;
|
||||
}
|
||||
|
||||
ret = spi_register_master(master);
|
||||
if (ret < 0)
|
||||
goto unreg_master;
|
||||
goto free_irq;
|
||||
|
||||
return ret;
|
||||
|
||||
unreg_master:
|
||||
destroy_workqueue(mps->workqueue);
|
||||
free_irq:
|
||||
free_irq(mps->irq, mps);
|
||||
free_master:
|
||||
|
|
@ -513,8 +546,6 @@ static int mpc512x_psc_spi_do_remove(struct device *dev)
|
|||
struct spi_master *master = spi_master_get(dev_get_drvdata(dev));
|
||||
struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
|
||||
|
||||
flush_workqueue(mps->workqueue);
|
||||
destroy_workqueue(mps->workqueue);
|
||||
spi_unregister_master(master);
|
||||
free_irq(mps->irq, mps);
|
||||
if (mps->psc)
|
||||
|
|
|
|||
Loading…
Reference in a new issue