[PATCH v2 2/8] spi: lantiq: Add SMP support

[Dilip Kota]

Existing driver supports only single core SoC. New multicore platforms uses
the same driver/IP so SMP support is required. This patch adds multicore
support in the driver.

Signed-off-by: Dilip Kota <eswara.k...@linux.intel.com>
---
 drivers/spi/spi-lantiq-ssc.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/spi/spi-lantiq-ssc.c b/drivers/spi/spi-lantiq-ssc.c
index 44600fb71c484..1073a70a4beba 100644
--- a/drivers/spi/spi-lantiq-ssc.c
+++ b/drivers/spi/spi-lantiq-ssc.c
@@ -623,7 +623,9 @@ static void rx_request(struct lantiq_ssc_spi *spi)
 static irqreturn_t lantiq_ssc_xmit_interrupt(int irq, void *data)
 {
        struct lantiq_ssc_spi *spi = data;
+       unsigned long flags;
 
+       spin_lock_irqsave(&spi->lock, flags);
        if (spi->tx) {
                if (spi->rx && spi->rx_todo)
                        rx_fifo_read_full_duplex(spi);
@@ -645,10 +647,12 @@ static irqreturn_t lantiq_ssc_xmit_interrupt(int irq, 
void *data)
                }
        }
 
+       spin_unlock_irqrestore(&spi->lock, flags);
        return IRQ_HANDLED;
 
 completed:
        queue_work(spi->wq, &spi->work);
+       spin_unlock_irqrestore(&spi->lock, flags);
 
        return IRQ_HANDLED;
 }
@@ -657,10 +661,12 @@ static irqreturn_t lantiq_ssc_err_interrupt(int irq, void 
*data)
 {
        struct lantiq_ssc_spi *spi = data;
        u32 stat = lantiq_ssc_readl(spi, LTQ_SPI_STAT);
+       unsigned long flags;
 
        if (!(stat & LTQ_SPI_STAT_ERRORS))
                return IRQ_NONE;
 
+       spin_lock_irqsave(&spi->lock, flags);
        if (stat & LTQ_SPI_STAT_RUE)
                dev_err(spi->dev, "receive underflow error\n");
        if (stat & LTQ_SPI_STAT_TUE)
@@ -681,6 +687,7 @@ static irqreturn_t lantiq_ssc_err_interrupt(int irq, void 
*data)
        if (spi->master->cur_msg)
                spi->master->cur_msg->status = -EIO;
        queue_work(spi->wq, &spi->work);
+       spin_unlock_irqrestore(&spi->lock, flags);
 
        return IRQ_HANDLED;
 }
-- 
2.11.0