[PATCH 3/5] spi: add functions ..._transfer_iobufs_n()

[Laurentiu-Cristian Duca via Xenomai]

From: Laurentiu-Cristian Duca <laurentiu.d...@gmail.com>

spi-bcm2835.c, spi-sun6i.c:
In order to support SPI_RTIOC_TRANSFER_N ioctl option
add functions bcm2835_transfer_iobufs_n() and sun6i_transfer_iobufs_n()
which are similar to ..._transfer_iobufs(),
but allow user specified len for spi transfer.

Signed-off-by: Laurentiu-Cristian Duca <laurentiu.d...@gmail.com>
---
 kernel/drivers/spi/spi-bcm2835.c | 19 +++++++++++++++++++
 kernel/drivers/spi/spi-sun6i.c   | 19 +++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/kernel/drivers/spi/spi-bcm2835.c b/kernel/drivers/spi/spi-bcm2835.c
index e4a95d081..fab6f6e77 100644
--- a/kernel/drivers/spi/spi-bcm2835.c
+++ b/kernel/drivers/spi/spi-bcm2835.c
@@ -318,6 +318,24 @@ static int bcm2835_transfer_iobufs(struct
rtdm_spi_remote_slave *slave)
        return do_transfer_irq(slave);
 }

+static int bcm2835_transfer_iobufs_n(struct rtdm_spi_remote_slave *slave,
+                                                                               
 int len)
+{
+       struct spi_master_bcm2835 *spim = to_master_bcm2835(slave);
+       struct spi_slave_bcm2835 *bcm = to_slave_bcm2835(slave);
+
+       if ((bcm->io_len == 0) ||
+               (len <= 0) || (len > (bcm->io_len / 2)))
+               return -EINVAL;
+
+       spim->tx_len = len;
+       spim->rx_len = len;
+       spim->tx_buf = bcm->io_virt + bcm->io_len / 2;
+       spim->rx_buf = bcm->io_virt;
+
+       return do_transfer_irq(slave);
+}
+
 static ssize_t bcm2835_read(struct rtdm_spi_remote_slave *slave,
                            void *rx, size_t len)
 {
@@ -549,6 +567,7 @@ static struct rtdm_spi_master_ops bcm2835_master_ops = {
        .mmap_iobufs = bcm2835_mmap_iobufs,
        .mmap_release = bcm2835_mmap_release,
        .transfer_iobufs = bcm2835_transfer_iobufs,
+       .transfer_iobufs_n = bcm2835_transfer_iobufs_n,
        .write = bcm2835_write,
        .read = bcm2835_read,
        .attach_slave = bcm2835_attach_slave,
diff --git a/kernel/drivers/spi/spi-sun6i.c b/kernel/drivers/spi/spi-sun6i.c
index ec08c98d8..940c98b31 100644
--- a/kernel/drivers/spi/spi-sun6i.c
+++ b/kernel/drivers/spi/spi-sun6i.c
@@ -355,6 +355,24 @@ static int sun6i_transfer_iobufs(struct
rtdm_spi_remote_slave *slave)
        return do_transfer_irq(slave);
 }

+static int sun6i_transfer_iobufs_n(struct rtdm_spi_remote_slave *slave,
+                                                                int len)
+{
+       struct spi_master_sun6i *spim = to_master_sun6i(slave);
+       struct spi_slave_sun6i *sun6i = to_slave_sun6i(slave);
+
+       if ((sun6i->io_len == 0) ||
+               (len <= 0) || (len > (sun6i->io_len / 2)))
+               return -EINVAL;
+
+       spim->tx_len = len;
+       spim->rx_len = len;
+       spim->tx_buf = sun6i->io_virt + sun6i->io_len / 2;
+       spim->rx_buf = sun6i->io_virt;
+
+       return do_transfer_irq(slave);
+}
+
 static ssize_t sun6i_read(struct rtdm_spi_remote_slave *slave,
                          void *rx, size_t len)
 {
@@ -480,6 +498,7 @@ static struct rtdm_spi_master_ops sun6i_master_ops = {
        .mmap_iobufs = sun6i_mmap_iobufs,
        .mmap_release = sun6i_mmap_release,
        .transfer_iobufs = sun6i_transfer_iobufs,
+       .transfer_iobufs_n = sun6i_transfer_iobufs_n,
        .write = sun6i_write,
        .read = sun6i_read,
        .attach_slave = sun6i_attach_slave,
-- 
2.17.1