From d500e922b750a2bea554d32d8f12937f4da9c80a Mon Sep 17 00:00:00 2001
From: Matteo Fortini <[EMAIL PROTECTED]>
Date: Wed, 10 Dec 2008 19:33:16 +0100
Subject: [PATCH] Fix: put dummy byte to enable fixing EOF bug to first
place in order not to break some drivers
Use ALARM interrupt to avoid waiting for data to come in
Signed-off-by: Matteo Fortini <[EMAIL PROTECTED]>
---
drivers/spi/mpc512x_psc_spi.c | 53
++++++++++++++++++++++++-----------------
1 files changed, 31 insertions(+), 22 deletions(-)
diff --git a/drivers/spi/mpc512x_psc_spi.c b/drivers/spi/mpc512x_psc_spi.c
index 1fd7ad4..41faa49 100644
--- a/drivers/spi/mpc512x_psc_spi.c
+++ b/drivers/spi/mpc512x_psc_spi.c
@@ -136,6 +136,7 @@ static void mpc512x_psc_spi_deactivate_cs(struct
spi_device *spi)
(spi->mode & SPI_CS_HIGH) ? 1 : 0);
}
+
/*
* Current MPC5121's have a bug in the SS logic that requires setting
* the EOF flag on the next to last byte instead of the last
@@ -155,7 +156,7 @@ static int mpc512x_psc_spi_transfer_rxtx(struct
spi_device *spi,
if (!tx_buf && !rx_buf && t->len)
return -EINVAL;
-
+
/*
* zero out Mode register 2
* From the ref man:
@@ -175,6 +176,7 @@ static int mpc512x_psc_spi_transfer_rxtx(struct
spi_device *spi,
u8 data;
size_t fifosz;
int rxcount;
+ int txcount;
/*
* The number of bytes that can be sent at a time
@@ -183,41 +185,49 @@ static int mpc512x_psc_spi_transfer_rxtx(struct
spi_device *spi,
fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->txsz));
count = min(fifosz, len);
+ txcount = 0;
+ /*
+ * Insert a dummy byte before a message of len 1 to make it at
least 2 bytes long
+ * to be able to set EOF correctly
+ */
+ if (t->len == 1) {
+ out_8(&fifo->txdata_8, 0);
+ txcount++;
+ }
for (i = count; i > 0; i--) {
if (len == EOFBYTE || t->len == 1)
setbits32(&fifo->txcmd, MPC512x_PSC_FIFO_EOF);
data = tx_buf ? *tx_buf++ : 0;
out_8(&fifo->txdata_8, data);
- if (t->len == 1)
- out_8(&fifo->txdata_8, 0);
+ txcount++;
len--;
}
INIT_COMPLETION(mps->done);
- /* interrupt on tx fifo empty */
- out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY);
- out_be32(&fifo->tximr, MPC512x_PSC_FIFO_EMPTY);
+ /* Enable FIFO_ALARM interrupts for rx_fifo */
+ out_be32(&fifo->rxalarm, txcount);
+ out_be32(&fifo->rxisr, MPC512x_PSC_FIFO_ALARM);
+ out_be32(&fifo->rximr, MPC512x_PSC_FIFO_ALARM);
- /* enable transmiter/receiver */
- out_8(&psc->command, MPC52xx_PSC_TX_ENABLE |
MPC52xx_PSC_RX_ENABLE);
-
- wait_for_completion(&mps->done);
+ /* Disable tx_fifo interrupts */
+ out_be32(&fifo->txisr, 0xffffffff);
+ out_be32(&fifo->tximr, 0);
- mdelay(1);
+ out_8(&psc->command, MPC52xx_PSC_TX_ENABLE |
MPC52xx_PSC_RX_ENABLE);
- /* rx fifo should have count bytes in it */
- rxcount = in_be32(&fifo->rxcnt);
- if (rxcount != count)
- mdelay(1);
+ wait_for_completion (&mps->done);
rxcount = in_be32(&fifo->rxcnt);
- if (rxcount != count && t->len != 1)
+ if (rxcount != txcount)
printk(KERN_WARNING "expected %d bytes in rx fifo "
- "but got %d\n", count, rxcount);
-
+ "but got %d\n", txcount, rxcount);
rxcount = min(rxcount, count);
{
+ /* Throw away possible initial dummy byte */
+ if (t->len == 1) {
+ (void)in_8(&fifo->rxdata_8);
+ }
for (i = rxcount; i > 0; i--) {
data = in_8(&fifo->rxdata_8);
if (rx_buf)
@@ -418,10 +428,9 @@ static irqreturn_t mpc512x_psc_spi_isr(int irq,
void *dev_id)
struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
/* clear interrupt and wake up the work queue */
- 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);
+ if (in_be32(&fifo->rxisr) & in_be32(&fifo->rximr) &
MPC512x_PSC_FIFO_ALARM) {
+ out_be32(&fifo->rxisr, MPC512x_PSC_FIFO_ALARM);
+ out_be32(&fifo->rximr, 0);
complete(&mps->done);
return IRQ_HANDLED;
}
--
1.5.4.3
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