Applied "spi: qup: Do block sized read/write in block mode" to the spi tree

[Mark Brown <broonie@kernel.org>]

The patch

   spi: qup: Do block sized read/write in block mode

has been applied to the spi tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 7538726f9ddaa53b72d61116728cf2d189b05202 Mon Sep 17 00:00:00 2001
From: Varadarajan Narayanan <varada@codeaurora.org>
Date: Fri, 28 Jul 2017 12:22:54 +0530
Subject: [PATCH] spi: qup: Do block sized read/write in block mode

This patch corrects the behavior of the BLOCK
transactions.  During block transactions, the controller
must be read/written to in block size transactions.

Signed-off-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Varadarajan Narayanan <varada@codeaurora.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 drivers/spi/spi-qup.c | 151 +++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 119 insertions(+), 32 deletions(-)

diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
index a7c630c4788c..8cfa112bb142 100644
--- a/drivers/spi/spi-qup.c
+++ b/drivers/spi/spi-qup.c
@@ -82,6 +82,8 @@
 #define QUP_IO_M_MODE_BAM		3
 
 /* QUP_OPERATIONAL fields */
+#define QUP_OP_IN_BLOCK_READ_REQ	BIT(13)
+#define QUP_OP_OUT_BLOCK_WRITE_REQ	BIT(12)
 #define QUP_OP_MAX_INPUT_DONE_FLAG	BIT(11)
 #define QUP_OP_MAX_OUTPUT_DONE_FLAG	BIT(10)
 #define QUP_OP_IN_SERVICE_FLAG		BIT(9)
@@ -154,6 +156,13 @@ struct spi_qup {
 	struct dma_slave_config	tx_conf;
 };
 
+static inline bool spi_qup_is_flag_set(struct spi_qup *controller, u32 flag)
+{
+	u32 opflag = readl_relaxed(controller->base + QUP_OPERATIONAL);
+
+	return (opflag & flag) != 0;
+}
+
 static inline bool spi_qup_is_dma_xfer(int mode)
 {
 	if (mode == QUP_IO_M_MODE_DMOV || mode == QUP_IO_M_MODE_BAM)
@@ -214,29 +223,26 @@ static int spi_qup_set_state(struct spi_qup *controller, u32 state)
 	return 0;
 }
 
-static void spi_qup_fifo_read(struct spi_qup *controller,
-			    struct spi_transfer *xfer)
+static void spi_qup_read_from_fifo(struct spi_qup *controller,
+	struct spi_transfer *xfer, u32 num_words)
 {
 	u8 *rx_buf = xfer->rx_buf;
-	u32 word, state;
-	int idx, shift, w_size;
+	int i, shift, num_bytes;
+	u32 word;
 
-	w_size = controller->w_size;
-
-	while (controller->rx_bytes < xfer->len) {
-
-		state = readl_relaxed(controller->base + QUP_OPERATIONAL);
-		if (0 == (state & QUP_OP_IN_FIFO_NOT_EMPTY))
-			break;
+	for (; num_words; num_words--) {
 
 		word = readl_relaxed(controller->base + QUP_INPUT_FIFO);
 
+		num_bytes = min_t(int, xfer->len - controller->rx_bytes,
+					controller->w_size);
+
 		if (!rx_buf) {
-			controller->rx_bytes += w_size;
+			controller->rx_bytes += num_bytes;
 			continue;
 		}
 
-		for (idx = 0; idx < w_size; idx++, controller->rx_bytes++) {
+		for (i = 0; i < num_bytes; i++, controller->rx_bytes++) {
 			/*
 			 * The data format depends on bytes per SPI word:
 			 *  4 bytes: 0x12345678
@@ -244,38 +250,80 @@ static void spi_qup_fifo_read(struct spi_qup *controller,
 			 *  1 byte : 0x00000012
 			 */
 			shift = BITS_PER_BYTE;
-			shift *= (w_size - idx - 1);
+			shift *= (controller->w_size - i - 1);
 			rx_buf[controller->rx_bytes] = word >> shift;
 		}
 	}
 }
 
-static void spi_qup_fifo_write(struct spi_qup *controller,
+static void spi_qup_read(struct spi_qup *controller,
 			    struct spi_transfer *xfer)
 {
-	const u8 *tx_buf = xfer->tx_buf;
-	u32 word, state, data;
-	int idx, w_size;
+	u32 remainder, words_per_block, num_words;
+	bool is_block_mode = controller->mode == QUP_IO_M_MODE_BLOCK;
+
+	remainder = DIV_ROUND_UP(xfer->len - controller->rx_bytes,
+				 controller->w_size);
+	words_per_block = controller->in_blk_sz >> 2;
+
+	do {
+		/* ACK by clearing service flag */
+		writel_relaxed(QUP_OP_IN_SERVICE_FLAG,
+			       controller->base + QUP_OPERATIONAL);
+
+		if (is_block_mode) {
+			num_words = (remainder > words_per_block) ?
+					words_per_block : remainder;
+		} else {
+			if (!spi_qup_is_flag_set(controller,
+						 QUP_OP_IN_FIFO_NOT_EMPTY))
+				break;
 
-	w_size = controller->w_size;
+			num_words = 1;
+		}
 
-	while (controller->tx_bytes < xfer->len) {
+		/* read up to the maximum transfer size available */
+		spi_qup_read_from_fifo(controller, xfer, num_words);
 
-		state = readl_relaxed(controller->base + QUP_OPERATIONAL);
-		if (state & QUP_OP_OUT_FIFO_FULL)
+		remainder -= num_words;
+
+		/* if block mode, check to see if next block is available */
+		if (is_block_mode && !spi_qup_is_flag_set(controller,
+					QUP_OP_IN_BLOCK_READ_REQ))
 			break;
 
+	} while (remainder);
+
+	/*
+	 * Due to extra stickiness of the QUP_OP_IN_SERVICE_FLAG during block
+	 * mode reads, it has to be cleared again at the very end
+	 */
+	if (is_block_mode && spi_qup_is_flag_set(controller,
+				QUP_OP_MAX_INPUT_DONE_FLAG))
+		writel_relaxed(QUP_OP_IN_SERVICE_FLAG,
+			       controller->base + QUP_OPERATIONAL);
+
+}
+
+static void spi_qup_write_to_fifo(struct spi_qup *controller,
+	struct spi_transfer *xfer, u32 num_words)
+{
+	const u8 *tx_buf = xfer->tx_buf;
+	int i, num_bytes;
+	u32 word, data;
+
+	for (; num_words; num_words--) {
 		word = 0;
-		for (idx = 0; idx < w_size; idx++, controller->tx_bytes++) {
 
-			if (!tx_buf) {
-				controller->tx_bytes += w_size;
-				break;
+		num_bytes = min_t(int, xfer->len - controller->tx_bytes,
+				    controller->w_size);
+		if (tx_buf)
+			for (i = 0; i < num_bytes; i++) {
+				data = tx_buf[controller->tx_bytes + i];
+				word |= data << (BITS_PER_BYTE * (3 - i));
 			}
 
-			data = tx_buf[controller->tx_bytes];
-			word |= data << (BITS_PER_BYTE * (3 - idx));
-		}
+		controller->tx_bytes += num_bytes;
 
 		writel_relaxed(word, controller->base + QUP_OUTPUT_FIFO);
 	}
@@ -288,6 +336,44 @@ static void spi_qup_dma_done(void *data)
 	complete(&qup->done);
 }
 
+static void spi_qup_write(struct spi_qup *controller,
+			    struct spi_transfer *xfer)
+{
+	bool is_block_mode = controller->mode == QUP_IO_M_MODE_BLOCK;
+	u32 remainder, words_per_block, num_words;
+
+	remainder = DIV_ROUND_UP(xfer->len - controller->tx_bytes,
+				 controller->w_size);
+	words_per_block = controller->out_blk_sz >> 2;
+
+	do {
+		/* ACK by clearing service flag */
+		writel_relaxed(QUP_OP_OUT_SERVICE_FLAG,
+			       controller->base + QUP_OPERATIONAL);
+
+		if (is_block_mode) {
+			num_words = (remainder > words_per_block) ?
+				words_per_block : remainder;
+		} else {
+			if (spi_qup_is_flag_set(controller,
+						QUP_OP_OUT_FIFO_FULL))
+				break;
+
+			num_words = 1;
+		}
+
+		spi_qup_write_to_fifo(controller, xfer, num_words);
+
+		remainder -= num_words;
+
+		/* if block mode, check to see if next block is available */
+		if (is_block_mode && !spi_qup_is_flag_set(controller,
+					QUP_OP_OUT_BLOCK_WRITE_REQ))
+			break;
+
+	} while (remainder);
+}
+
 static int spi_qup_prep_sg(struct spi_master *master, struct spi_transfer *xfer,
 			   enum dma_transfer_direction dir,
 			   dma_async_tx_callback callback)
@@ -391,7 +477,8 @@ static int spi_qup_do_pio(struct spi_master *master, struct spi_transfer *xfer,
 		return ret;
 	}
 
-	spi_qup_fifo_write(qup, xfer);
+	if (qup->mode == QUP_IO_M_MODE_FIFO)
+		spi_qup_write(qup, xfer);
 
 	ret = spi_qup_set_state(qup, QUP_STATE_RUN);
 	if (ret) {
@@ -446,10 +533,10 @@ static irqreturn_t spi_qup_qup_irq(int irq, void *dev_id)
 		writel_relaxed(opflags, controller->base + QUP_OPERATIONAL);
 	} else {
 		if (opflags & QUP_OP_IN_SERVICE_FLAG)
-			spi_qup_fifo_read(controller, xfer);
+			spi_qup_read(controller, xfer);
 
 		if (opflags & QUP_OP_OUT_SERVICE_FLAG)
-			spi_qup_fifo_write(controller, xfer);
+			spi_qup_write(controller, xfer);
 	}
 
 	if ((opflags & QUP_OP_MAX_INPUT_DONE_FLAG) || error)
-- 
2.13.2