2 files changed, 44 insertions, 26 deletions

diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
index f04c2464e854..95c1fbfe1cbe 100644
--- a/drivers/spi/spi-fsl-espi.c
+++ b/drivers/spi/spi-fsl-espi.c
@@ -54,6 +54,8 @@
 #define CSMODE_AFT(x)		((x) << 8)
 #define CSMODE_CG(x)		((x) << 3)
 
+#define FSL_ESPI_FIFO_SIZE	32
+
 /* Default mode/csmode for eSPI controller */
 #define SPMODE_INIT_VAL (SPMODE_TXTHR(4) | SPMODE_RXTHR(3))
 #define CSMODE_INIT_VAL (CSMODE_POL_1 | CSMODE_BEF(0) \
@@ -200,6 +202,27 @@ static int fsl_espi_check_message(struct spi_message *m)
 	return 0;
 }
 
+static void fsl_espi_fill_tx_fifo(struct mpc8xxx_spi *mspi, u32 events)
+{
+	u32 tx_fifo_avail;
+
+	/* if events is zero transfer has not started and tx fifo is empty */
+	tx_fifo_avail = events ? SPIE_TXCNT(events) :  FSL_ESPI_FIFO_SIZE;
+
+	while (tx_fifo_avail >= min(4U, mspi->tx_len) && mspi->tx_len)
+		if (mspi->tx_len >= 4) {
+			fsl_espi_write_reg(mspi, ESPI_SPITF, *(u32 *)mspi->tx);
+			mspi->tx += 4;
+			mspi->tx_len -= 4;
+			tx_fifo_avail -= 4;
+		} else {
+			fsl_espi_write_reg8(mspi, ESPI_SPITF, *(u8 *)mspi->tx);
+			mspi->tx += 1;
+			mspi->tx_len -= 1;
+			tx_fifo_avail -= 1;
+		}
+}
+
 static void fsl_espi_change_mode(struct spi_device *spi)
 {
 	struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
@@ -262,7 +285,7 @@ static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t)
 	int ret;
 
 	mpc8xxx_spi->len = t->len;
-	mpc8xxx_spi->count = roundup(t->len, 4) / 4;
+	mpc8xxx_spi->tx_len = t->len;
 
 	mpc8xxx_spi->tx = t->tx_buf;
 	mpc8xxx_spi->rx = t->rx_buf;
@@ -276,21 +299,22 @@ static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t)
 	/* enable rx ints */
 	fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPIM, SPIM_RNE);
 
-	/* transmit word */
-	fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPITF, *(u32 *)mpc8xxx_spi->tx);
-	mpc8xxx_spi->tx += 4;
+	/* Prevent filling the fifo from getting interrupted */
+	spin_lock_irq(&mpc8xxx_spi->lock);
+	fsl_espi_fill_tx_fifo(mpc8xxx_spi, 0);
+	spin_unlock_irq(&mpc8xxx_spi->lock);
 
 	/* Won't hang up forever, SPI bus sometimes got lost interrupts... */
 	ret = wait_for_completion_timeout(&mpc8xxx_spi->done, 2 * HZ);
 	if (ret == 0)
 		dev_err(mpc8xxx_spi->dev,
-			"Transaction hanging up (left %d bytes)\n",
-			mpc8xxx_spi->count);
+			"Transaction hanging up (left %u bytes)\n",
+			mpc8xxx_spi->tx_len);
 
 	/* disable rx ints */
 	fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPIM, 0);
 
-	return mpc8xxx_spi->count > 0 ? -EMSGSIZE : 0;
+	return mpc8xxx_spi->tx_len > 0 ? -EMSGSIZE : 0;
 }
 
 static int fsl_espi_trans(struct spi_message *m, struct spi_transfer *trans)
@@ -461,26 +485,11 @@ static void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events)
 		}
 	}
 
-	if (!(events & SPIE_TNF)) {
-		int ret;
-
-		/* spin until TX is done */
-		ret = spin_event_timeout(((events = fsl_espi_read_reg(
-				mspi, ESPI_SPIE)) & SPIE_TNF), 1000, 0);
-		if (!ret) {
-			dev_err(mspi->dev, "tired waiting for SPIE_TNF\n");
-			complete(&mspi->done);
-			return;
-		}
-	}
+	if (mspi->tx_len)
+		fsl_espi_fill_tx_fifo(mspi, events);
 
-	mspi->count -= 1;
-	if (mspi->count) {
-		fsl_espi_write_reg(mspi, ESPI_SPITF, *(u32 *)mspi->tx);
-		mspi->tx += 4;
-	} else {
+	if (!mspi->tx_len && !mspi->len)
 		complete(&mspi->done);
-	}
 }
 
 static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
@@ -488,10 +497,14 @@ static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
 	struct mpc8xxx_spi *mspi = context_data;
 	u32 events;
 
+	spin_lock(&mspi->lock);
+
 	/* Get interrupt events(tx/rx) */
 	events = fsl_espi_read_reg(mspi, ESPI_SPIE);
-	if (!events)
+	if (!events) {
+		spin_unlock_irq(&mspi->lock);
 		return IRQ_NONE;
+	}
 
 	dev_vdbg(mspi->dev, "%s: events %x\n", __func__, events);
 
@@ -500,6 +513,8 @@ static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
 	/* Clear the events */
 	fsl_espi_write_reg(mspi, ESPI_SPIE, events);
 
+	spin_unlock(&mspi->lock);
+
 	return IRQ_HANDLED;
 }
 
@@ -562,6 +577,7 @@ static int fsl_espi_probe(struct device *dev, struct resource *mem,
 	master->max_message_size = fsl_espi_max_message_size;
 
 	mpc8xxx_spi = spi_master_get_devdata(master);
+	spin_lock_init(&mpc8xxx_spi->lock);
 
 	mpc8xxx_spi->local_buf =
 		devm_kmalloc(dev, SPCOM_TRANLEN_MAX, GFP_KERNEL);
diff --git a/drivers/spi/spi-fsl-lib.h b/drivers/spi/spi-fsl-lib.h
index 2925c8089fd9..24d8bc84a111 100644
--- a/drivers/spi/spi-fsl-lib.h
+++ b/drivers/spi/spi-fsl-lib.h
@@ -30,7 +30,9 @@ struct mpc8xxx_spi {
 	void *rx;
 #if IS_ENABLED(CONFIG_SPI_FSL_ESPI)
 	int len;
+	unsigned int tx_len;
 	u8 *local_buf;
+	spinlock_t lock;
 #endif
 
 	int subblock;