[PATCH 09/18] spi: qup: Do block sized read/write in block mode

Varadarajan Narayanan
2017-06-14T05:54:07Z

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>
---
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 0f6a4c7..872de28 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)
@@ -156,6 +158,13 @@ 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)
@@ -216,29 +225,26 @@ 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
@@ -246,38 +252,80 @@ 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(data);
}

+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, void *data)
@@ -390,7 +476,8 @@ 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) {
@@ -455,10 +542,10 @@ static irqreturn_t spi_qup_qup_irq(int irq, void *dev_id)

if (!spi_qup_is_dma_xfer(controller->mode)) {
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);
}

spin_lock_irqsave(&controller->lock, flags);