Den 10.03.2018 16.51, skrev Meghana Madhyastha:

Split spi messages into chunks of <65535 in the spi subsystem and remove the message length warning in bcm2835_spi_can_dma. This is so that the messages can be transferred via dma and that the tinydrm drivers need not split it.

Signed-off-by: Meghana Madhyastha meghana.madhyastha@gmail.com

drivers/spi/spi-bcm2835.c | 13 ------------- drivers/spi/spi.c | 8 ++++++++ 2 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index f35cc10772f6..0dcc45f158b8 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -365,19 +365,6 @@ static bool bcm2835_spi_can_dma(struct spi_master *master, if (tfr->len < BCM2835_SPI_DMA_MIN_LENGTH) return false;

• /* BCM2835_SPI_DLEN has defined a max transfer size as

• * 16 bit, so max is 65535
  

• * we can revisit this by using an alternative transfer
  

• * method - ideally this would get done without any more
  

• * interaction...
  

• */
  

• if (tfr->len > 65535) {

• dev_warn_once(&spi->dev,
  

• 	      "transfer size of %d too big for dma-transfer\n",
  

• 	      tfr->len);
  

• return false;
  

• }
• /* if we run rx/tx_buf with word aligned addresses then we are OK */ if ((((size_t)tfr->rx_buf & 3) == 0) && (((size_t)tfr->tx_buf & 3) == 0))

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index b33a727a0158..e8e2c366a93b 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1242,6 +1242,14 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread) trace_spi_message_start(ctlr->cur_msg);

if (ctlr->prepare_message) {

• gfp_t gfp_flags = GFP_KERNEL | GFP_DMA;
  

• size_t max_transfer_size = 32000;
  

What number is this?

As Geert says, this shouldn't be in the core but in the driver callback bcm2835_spi_prepare_message().

Noralf.

• ret = spi_split_transfers_maxsize(ctlr, ctlr->cur_msg, max_transfer_size, gfp_flags);
  

• if (ret) {
  

• 	dev_err(&ctlr->dev,
  

• 		"failed to split message\n");
  

• 	goto out;
  

• }
  

  ret = ctlr->prepare_message(ctlr, ctlr->cur_msg); if (ret) { dev_err(&ctlr->dev, "failed to prepare message: %d\n",

Den 10.03.2018 16.52, skrev Meghana Madhyastha:

Remove chunk splitting in tinydrm_spi_transfer in tinydrm-helpers as the spi core will split a buffer into max_dma_len chunks for the spi controller driver to handle, automatic byte swapping in tinydrm_spi_transfer as it doesn't have users.

Signed-off-by: Meghana Madhyastha meghana.madhyastha@gmail.com

drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c | 48 ++++---------------------- drivers/gpu/drm/tinydrm/mipi-dbi.c | 10 ++---- drivers/spi/spi-bcm2835.c | 2 +- 3 files changed, 9 insertions(+), 51 deletions(-)

diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c index bf96072d1b97..6064099e8e63 100644 --- a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c +++ b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c @@ -452,62 +452,26 @@ int tinydrm_spi_transfer(struct spi_device *spi, u32 speed_hz, struct spi_transfer tr = { .bits_per_word = bpw, .speed_hz = speed_hz,

• .tx_buf = buf,
  

• .len = len
  

  }; struct spi_message m;

• u16 *swap_buf = NULL; size_t max_chunk;

• size_t chunk;

• int ret = 0;

• if (WARN_ON_ONCE(bpw != 8 && bpw != 16))

• return -EINVAL;
  

• max_chunk = tinydrm_spi_max_transfer_size(spi, 0);

• max_chunk = SIZE_MAX;

max_chunk isn't used so can be removed. tinydrm_spi_max_transfer_size() can also be remove now.

if (drm_debug & DRM_UT_DRIVER) pr_debug("[drm:%s] bpw=%u, max_chunk=%zu, transfers:\n",

• 	 __func__, bpw, max_chunk);
  

• if (bpw == 16 && !tinydrm_spi_bpw_supported(spi, 16)) {

• tr.bits_per_word = 8;
  

• if (tinydrm_machine_little_endian()) {
  

• 	swap_buf = kmalloc(min(len, max_chunk), GFP_KERNEL);
  

• 	if (!swap_buf)
  

• 		return -ENOMEM;
  

• }
  

• }

• 	__func__, bpw, max_chunk);
  
  

  spi_message_init(&m); if (header) spi_message_add_tail(header, &m); spi_message_add_tail(&tr, &m);

• while (len) {

• chunk = min(len, max_chunk);
  

• tr.tx_buf = buf;
  

• tr.len = chunk;
  

• if (swap_buf) {
  

• 	const u16 *buf16 = buf;
  

• 	unsigned int i;
  

• 	for (i = 0; i < chunk / 2; i++)
  

• 		swap_buf[i] = swab16(buf16[i]);
  

• 	tr.tx_buf = swap_buf;
  

• }
  

• buf += chunk;
  

• len -= chunk;
  

• tinydrm_dbg_spi_message(spi, &m);
  

• ret = spi_sync(spi, &m);
  

• if (ret)
  

• 	return ret;
  

• }

• tinydrm_dbg_spi_message(spi, &m);

• return 0;

• return spi_sync(spi, &m); } EXPORT_SYMBOL(tinydrm_spi_transfer);

diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c b/drivers/gpu/drm/tinydrm/mipi-dbi.c index 75dd65c57e74..c8af2d65c2ad 100644 --- a/drivers/gpu/drm/tinydrm/mipi-dbi.c +++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c @@ -886,15 +886,9 @@ static int mipi_dbi_typec3_command(struct mipi_dbi *mipi, u8 cmd, int mipi_dbi_spi_init(struct spi_device *spi, struct mipi_dbi *mipi, struct gpio_desc *dc) {

• size_t tx_size = tinydrm_spi_max_transfer_size(spi, 0); struct device *dev = &spi->dev; int ret;

• if (tx_size < 16) {

• DRM_ERROR("SPI transmit buffer too small: %zu\n", tx_size);
  

• return -EINVAL;
  

• }

• /*

  • Even though it's not the SPI device that does DMA (the master does),
  • the dma mask is necessary for the dma_alloc_wc() in

@@ -924,8 +918,8 @@ int mipi_dbi_spi_init(struct spi_device *spi, struct mipi_dbi *mipi, mipi->swap_bytes = true; } else { mipi->command = mipi_dbi_typec1_command;

• mipi->tx_buf9_len = tx_size;
  

• mipi->tx_buf9 = devm_kmalloc(dev, tx_size, GFP_KERNEL);
  

• mipi->tx_buf9_len = SZ_16K;
  

• mipi->tx_buf9 = devm_kmalloc(dev, mipi->tx_buf9_len, GFP_KERNEL);
  

  if (!mipi->tx_buf9) return -ENOMEM; }

diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index 0dcc45f158b8..2fd650891c07 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -448,7 +448,7 @@ static void bcm2835_dma_init(struct spi_master *master, struct device *dev)

/* all went well, so set can_dma */ master->can_dma = bcm2835_spi_can_dma;

• master->max_dma_len = 65535; /* limitation by BCM2835_SPI_DLEN */

• master->max_dma_len = 65528; /* limitation by BCM2835_SPI_DLEN */

This change belongs in the spi-bcm2835 patch. You need to tell us why the change is needed.

Noralf.

/* need to do TX AND RX DMA, so we need dummy buffers */ master->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX;