[PORT FROM R2] hsu: port recent fix from R2

BZ: 21502

The fix hsu: turn off RX dma before runtime suspend was merged in R2
need port it to R3.(BZ 18936)

Also include a fix for holding tty ref during rx dma handling.(BZ 21234)

Change-Id: I88647c9fb50d7f8c3056b70d37b5a8fe972ec645
Signed-off-by: Alek Du <alek.du@intel.com>
Reviewed-on: http://android.intel.com:8080/33119
Reviewed-by: Cai, Stanley W <stanley.w.cai@intel.com>
Tested-by: Wang, Zhifeng <zhifeng.wang@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>

diff --git a/drivers/tty/serial/mfd.c b/drivers/tty/serial/mfd.c
index 79874df..58bfed8 100644 (file)
--- a/drivers/tty/serial/mfd.c
+++ b/drivers/tty/serial/mfd.c
@@ -97,6 +97,7 @@ struct uart_hsu_port {
        int                     use_dma;        /* flag for DMA/PIO */
        int                     running;
        int                     dma_tx_on;
+       int                     dma_rx_on;
        char                    reg_shadow[HSU_PORT_REG_LENGTH];
        struct circ_buf         qcirc;
        int                     qbuf[MAXQ * 3]; /* cmd + offset + value */
@@ -493,8 +494,11 @@ void hsu_dma_tx(struct uart_hsu_port *up)
 }
 
 /* The buffer is already cache coherent */
-void hsu_dma_start_rx_chan(struct hsu_dma_chan *rxc, struct hsu_dma_buffer *dbuf)
+void hsu_dma_start_rx_chan(struct uart_hsu_port *up,
+                       struct hsu_dma_buffer *dbuf)
 {
+       struct hsu_dma_chan *rxc = up->rxc;
+
        dbuf->ofs = 0;
 
        chan_writel(rxc, HSU_CH_BSR, 32);
@@ -507,6 +511,7 @@ void hsu_dma_start_rx_chan(struct hsu_dma_chan *rxc, struct hsu_dma_buffer *dbuf
                                         | (0x1 << 24)  /* timeout bit, see HSU Errata 1 */
                                         );
        chan_writel(rxc, HSU_CH_CR, 0x3);
+       up->dma_rx_on = 1;
 
        if (dmarx_need_timer())
                mod_timer(&rxc->rx_timer, jiffies + HSU_DMA_TIMEOUT_CHECK_FREQ);
@@ -544,9 +549,10 @@ static void serial_hsu_stop_tx(struct uart_port *port)
        struct hsu_dma_chan *txc = up->txc;
 
        pm_runtime_get(up->dev);
-       if (up->use_dma)
+       if (up->use_dma) {
                chan_writel(txc, HSU_CH_CR, 0x0);
-       else if (up->ier & UART_IER_THRI) {
+               up->dma_tx_on = 0;
+       } else if (up->ier & UART_IER_THRI) {
                up->ier &= ~UART_IER_THRI;
                serial_out(up, UART_IER, up->ier);
        }
@@ -603,9 +609,10 @@ void hsu_dma_rx(struct uart_hsu_port *up, u32 int_sts)
        struct hsu_dma_buffer *dbuf = &up->rxbuf;
        struct hsu_dma_chan *chan = up->rxc;
        struct uart_port *port = &up->port;
-       struct tty_struct *tty = port->state->port.tty;
+       struct tty_struct *tty;
        int count;
 
+       tty = tty_port_tty_get(&up->port.state->port);
        if (!tty)
                return;
 
@@ -627,6 +634,7 @@ void hsu_dma_rx(struct uart_hsu_port *up, u32 int_sts)
        if (!count) {
                /* Restart the channel before we leave */
                chan_writel(chan, HSU_CH_CR, 0x3);
+               tty_kref_put(tty);
                return;
        }
 
@@ -665,6 +673,7 @@ void hsu_dma_rx(struct uart_hsu_port *up, u32 int_sts)
                /* Directly call the remainder of hsu_dma_rx function
                 * form IRQ context */
                hsu_dma_rx_tasklet((unsigned long)up);
+       tty_kref_put(tty);
 }
 
 
@@ -683,6 +692,7 @@ static void serial_hsu_stop_rx(struct uart_port *port)
                } else {
                        chan_writel(up->rxc, HSU_CH_CR, 0x2);
                }
+               up->dma_rx_on = 0;
        } else {
                up->ier &= ~UART_IER_RLSI;
                up->port.read_status_mask &= ~UART_LSR_DR;
@@ -905,7 +915,7 @@ static inline void dma_chan_irq(struct hsu_dma_chan *chan)
                goto exit;
 
        /* Rx channel */
-       if (chan->dirt == DMA_FROM_DEVICE)
+       if (up->dma_rx_on && chan->dirt == DMA_FROM_DEVICE)
                hsu_dma_rx(up, int_sts);
 
        /* Tx channel */
@@ -1101,7 +1111,7 @@ static int serial_hsu_startup(struct uart_port *port)
                dbuf->dma_size = HSU_DMA_BUF_SIZE;
 
                /* Start the RX channel right now */
-               hsu_dma_start_rx_chan(up->rxc, dbuf);
+               hsu_dma_start_rx_chan(up, dbuf);
 
                /* Next init the TX DMA */
                dbuf = &up->txbuf;
@@ -1933,6 +1943,7 @@ static int hsu_runtime_suspend(struct device *dev)
        if (!allow_for_suspend(up))
                return hsu_runtime_idle(dev);
 
+       chan_writel(up->rxc, HSU_CH_CR, 0x2);
        disable_irq(up->port.irq);
        if (up->index == 1) {
                struct uart_hsu_port *up3 = serial_hsu_ports[3];
@@ -1953,6 +1964,7 @@ static int hsu_runtime_resume(struct device *dev)
 {
        struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
        struct uart_hsu_port *up = pci_get_drvdata(pdev);
+       int dma_rx_on = 0;
 
        if (up->running)
                mfld_hsu_disable_wakeup(up->index, dev);
@@ -1961,9 +1973,13 @@ static int hsu_runtime_resume(struct device *dev)
 
                if (up3->running)
                        mfld_hsu_disable_wakeup(up3->index, dev);
+               if (up3->dma_rx_on)
+                       dma_rx_on = 1;
        }
 
        enable_irq(up->port.irq);
+       if (up->dma_rx_on || dma_rx_on)
+               chan_writel(up->rxc, HSU_CH_CR, 0x3);
        return 0;
 }
 #endif