3 files changed, 569 insertions, 33 deletions

diff --git a/drivers/serial/amba-pl011.c b/drivers/serial/amba-pl011.c
index 6ca7a44f29c2..e76d7d000128 100644
--- a/drivers/serial/amba-pl011.c
+++ b/drivers/serial/amba-pl011.c
@@ -7,6 +7,7 @@
  *
  *  Copyright 1999 ARM Limited
  *  Copyright (C) 2000 Deep Blue Solutions Ltd.
+ *  Copyright (C) 2010 ST-Ericsson SA
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -48,6 +49,9 @@
 #include <linux/amba/serial.h>
 #include <linux/clk.h>
 #include <linux/slab.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/scatterlist.h>
 
 #include <asm/io.h>
 #include <asm/sizes.h>
@@ -63,21 +67,6 @@
 #define UART_DR_ERROR           (UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE)
 #define UART_DUMMY_DR_RX        (1 << 16)
 
-/*
- * We wrap our port structure around the generic uart_port.
- */
-struct uart_amba_port {
-        struct uart_port        port;
-        struct clk              *clk;
-        unsigned int            im;             /* interrupt mask */
-        unsigned int            old_status;
-        unsigned int            ifls;           /* vendor-specific */
-        unsigned int            lcrh_tx;        /* vendor-specific */
-        unsigned int            lcrh_rx;        /* vendor-specific */
-        bool                    oversampling;   /* vendor-specific */
-        bool                    autorts;
-};
-
 /* There is by now at least one vendor with differing details, so handle it */
 struct vendor_data {
         unsigned int            ifls;
@@ -85,6 +74,7 @@ struct vendor_data {
         unsigned int            lcrh_tx;
         unsigned int            lcrh_rx;
         bool                    oversampling;
+        bool                    dma_threshold;
 };
 
 static struct vendor_data vendor_arm = {
@@ -93,6 +83,7 @@ static struct vendor_data vendor_arm = {
         .lcrh_tx                = UART011_LCRH,
         .lcrh_rx                = UART011_LCRH,
         .oversampling           = false,
+        .dma_threshold          = false,
 };
 
 static struct vendor_data vendor_st = {
@@ -101,22 +92,535 @@ static struct vendor_data vendor_st = {
         .lcrh_tx                = ST_UART011_LCRH_TX,
         .lcrh_rx                = ST_UART011_LCRH_RX,
         .oversampling           = true,
+        .dma_threshold          = true,
+};
+
+/* Deals with DMA transactions */
+struct pl011_dmatx_data {
+        struct dma_chan         *chan;
+        struct scatterlist      sg;
+        char                    *buf;
+        bool                    queued;
 };
 
+/*
+ * We wrap our port structure around the generic uart_port.
+ */
+struct uart_amba_port {
+        struct uart_port        port;
+        struct clk              *clk;
+        const struct vendor_data *vendor;
+        unsigned int            dmacr;          /* dma control reg */
+        unsigned int            im;             /* interrupt mask */
+        unsigned int            old_status;
+        unsigned int            fifosize;       /* vendor-specific */
+        unsigned int            lcrh_tx;        /* vendor-specific */
+        unsigned int            lcrh_rx;        /* vendor-specific */
+        bool                    autorts;
+        char                    type[12];
+#ifdef CONFIG_DMA_ENGINE
+        /* DMA stuff */
+        bool                    using_dma;
+        struct pl011_dmatx_data dmatx;
+#endif
+};
+
+/*
+ * All the DMA operation mode stuff goes inside this ifdef.
+ * This assumes that you have a generic DMA device interface,
+ * no custom DMA interfaces are supported.
+ */
+#ifdef CONFIG_DMA_ENGINE
+
+#define PL011_DMA_BUFFER_SIZE PAGE_SIZE
+
+static void pl011_dma_probe_initcall(struct uart_amba_port *uap)
+{
+        /* DMA is the sole user of the platform data right now */
+        struct amba_pl011_data *plat = uap->port.dev->platform_data;
+        struct dma_slave_config tx_conf = {
+                .dst_addr = uap->port.mapbase + UART01x_DR,
+                .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
+                .direction = DMA_TO_DEVICE,
+                .dst_maxburst = uap->fifosize >> 1,
+        };
+        struct dma_chan *chan;
+        dma_cap_mask_t mask;
+
+        /* We need platform data */
+        if (!plat || !plat->dma_filter) {
+                dev_info(uap->port.dev, "no DMA platform data\n");
+                return;
+        }
+
+        /* Try to acquire a generic DMA engine slave channel */
+        dma_cap_zero(mask);
+        dma_cap_set(DMA_SLAVE, mask);
+
+        chan = dma_request_channel(mask, plat->dma_filter, plat->dma_tx_param);
+        if (!chan) {
+                dev_err(uap->port.dev, "no TX DMA channel!\n");
+                return;
+        }
+
+        dmaengine_slave_config(chan, &tx_conf);
+        uap->dmatx.chan = chan;
+
+        dev_info(uap->port.dev, "DMA channel TX %s\n",
+                 dma_chan_name(uap->dmatx.chan));
+}
+
+#ifndef MODULE
+/*
+ * Stack up the UARTs and let the above initcall be done at device
+ * initcall time, because the serial driver is called as an arch
+ * initcall, and at this time the DMA subsystem is not yet registered.
+ * At this point the driver will switch over to using DMA where desired.
+ */
+struct dma_uap {
+        struct list_head node;
+        struct uart_amba_port *uap;
+};
+
+static LIST_HEAD(pl011_dma_uarts);
+
+static int __init pl011_dma_initcall(void)
+{
+        struct list_head *node, *tmp;
+
+        list_for_each_safe(node, tmp, &pl011_dma_uarts) {
+                struct dma_uap *dmau = list_entry(node, struct dma_uap, node);
+                pl011_dma_probe_initcall(dmau->uap);
+                list_del(node);
+                kfree(dmau);
+        }
+        return 0;
+}
+
+device_initcall(pl011_dma_initcall);
+
+static void pl011_dma_probe(struct uart_amba_port *uap)
+{
+        struct dma_uap *dmau = kzalloc(sizeof(struct dma_uap), GFP_KERNEL);
+        if (dmau) {
+                dmau->uap = uap;
+                list_add_tail(&dmau->node, &pl011_dma_uarts);
+        }
+}
+#else
+static void pl011_dma_probe(struct uart_amba_port *uap)
+{
+        pl011_dma_probe_initcall(uap);
+}
+#endif
+
+static void pl011_dma_remove(struct uart_amba_port *uap)
+{
+        /* TODO: remove the initcall if it has not yet executed */
+        if (uap->dmatx.chan)
+                dma_release_channel(uap->dmatx.chan);
+}
+
+
+/* Forward declare this for the refill routine */
+static int pl011_dma_tx_refill(struct uart_amba_port *uap);
+
+/*
+ * The current DMA TX buffer has been sent.
+ * Try to queue up another DMA buffer.
+ */
+static void pl011_dma_tx_callback(void *data)
+{
+        struct uart_amba_port *uap = data;
+        struct pl011_dmatx_data *dmatx = &uap->dmatx;
+        unsigned long flags;
+        u16 dmacr;
+
+        spin_lock_irqsave(&uap->port.lock, flags);
+        if (uap->dmatx.queued)
+                dma_unmap_sg(dmatx->chan->device->dev, &dmatx->sg, 1,
+                             DMA_TO_DEVICE);
+
+        dmacr = uap->dmacr;
+        uap->dmacr = dmacr & ~UART011_TXDMAE;
+        writew(uap->dmacr, uap->port.membase + UART011_DMACR);
+
+        /*
+         * If TX DMA was disabled, it means that we've stopped the DMA for
+         * some reason (eg, XOFF received, or we want to send an X-char.)
+         *
+         * Note: we need to be careful here of a potential race between DMA
+         * and the rest of the driver - if the driver disables TX DMA while
+         * a TX buffer completing, we must update the tx queued status to
+         * get further refills (hence we check dmacr).
+         */
+        if (!(dmacr & UART011_TXDMAE) || uart_tx_stopped(&uap->port) ||
+            uart_circ_empty(&uap->port.state->xmit)) {
+                uap->dmatx.queued = false;
+                spin_unlock_irqrestore(&uap->port.lock, flags);
+                return;
+        }
+
+        if (pl011_dma_tx_refill(uap) <= 0) {
+                /*
+                 * We didn't queue a DMA buffer for some reason, but we
+                 * have data pending to be sent.  Re-enable the TX IRQ.
+                 */
+                uap->im |= UART011_TXIM;
+                writew(uap->im, uap->port.membase + UART011_IMSC);
+        }
+        spin_unlock_irqrestore(&uap->port.lock, flags);
+}
+
+/*
+ * Try to refill the TX DMA buffer.
+ * Locking: called with port lock held and IRQs disabled.
+ * Returns:
+ *   1 if we queued up a TX DMA buffer.
+ *   0 if we didn't want to handle this by DMA
+ *  <0 on error
+ */
+static int pl011_dma_tx_refill(struct uart_amba_port *uap)
+{
+        struct pl011_dmatx_data *dmatx = &uap->dmatx;
+        struct dma_chan *chan = dmatx->chan;
+        struct dma_device *dma_dev = chan->device;
+        struct dma_async_tx_descriptor *desc;
+        struct circ_buf *xmit = &uap->port.state->xmit;
+        unsigned int count;
+
+        /*
+         * Try to avoid the overhead involved in using DMA if the
+         * transaction fits in the first half of the FIFO, by using
+         * the standard interrupt handling.  This ensures that we
+         * issue a uart_write_wakeup() at the appropriate time.
+         */
+        count = uart_circ_chars_pending(xmit);
+        if (count < (uap->fifosize >> 1)) {
+                uap->dmatx.queued = false;
+                return 0;
+        }
+
+        /*
+         * Bodge: don't send the last character by DMA, as this
+         * will prevent XON from notifying us to restart DMA.
+         */
+        count -= 1;
+
+        /* Else proceed to copy the TX chars to the DMA buffer and fire DMA */
+        if (count > PL011_DMA_BUFFER_SIZE)
+                count = PL011_DMA_BUFFER_SIZE;
+
+        if (xmit->tail < xmit->head)
+                memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], count);
+        else {
+                size_t first = UART_XMIT_SIZE - xmit->tail;
+                size_t second = xmit->head;
+
+                memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], first);
+                if (second)
+                        memcpy(&dmatx->buf[first], &xmit->buf[0], second);
+        }
+
+        dmatx->sg.length = count;
+
+        if (dma_map_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE) != 1) {
+                uap->dmatx.queued = false;
+                dev_dbg(uap->port.dev, "unable to map TX DMA\n");
+                return -EBUSY;
+        }
+
+        desc = dma_dev->device_prep_slave_sg(chan, &dmatx->sg, 1, DMA_TO_DEVICE,
+                                             DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+        if (!desc) {
+                dma_unmap_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE);
+                uap->dmatx.queued = false;
+                /*
+                 * If DMA cannot be used right now, we complete this
+                 * transaction via IRQ and let the TTY layer retry.
+                 */
+                dev_dbg(uap->port.dev, "TX DMA busy\n");
+                return -EBUSY;
+        }
+
+        /* Some data to go along to the callback */
+        desc->callback = pl011_dma_tx_callback;
+        desc->callback_param = uap;
+
+        /* All errors should happen at prepare time */
+        dmaengine_submit(desc);
+
+        /* Fire the DMA transaction */
+        dma_dev->device_issue_pending(chan);
+
+        uap->dmacr |= UART011_TXDMAE;
+        writew(uap->dmacr, uap->port.membase + UART011_DMACR);
+        uap->dmatx.queued = true;
+
+        /*
+         * Now we know that DMA will fire, so advance the ring buffer
+         * with the stuff we just dispatched.
+         */
+        xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
+        uap->port.icount.tx += count;
+
+        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+                uart_write_wakeup(&uap->port);
+
+        return 1;
+}
+
+/*
+ * We received a transmit interrupt without a pending X-char but with
+ * pending characters.
+ * Locking: called with port lock held and IRQs disabled.
+ * Returns:
+ *   false if we want to use PIO to transmit
+ *   true if we queued a DMA buffer
+ */
+static bool pl011_dma_tx_irq(struct uart_amba_port *uap)
+{
+        if (!uap->using_dma)
+                return false;
+
+        /*
+         * If we already have a TX buffer queued, but received a
+         * TX interrupt, it will be because we've just sent an X-char.
+         * Ensure the TX DMA is enabled and the TX IRQ is disabled.
+         */
+        if (uap->dmatx.queued) {
+                uap->dmacr |= UART011_TXDMAE;
+                writew(uap->dmacr, uap->port.membase + UART011_DMACR);
+                uap->im &= ~UART011_TXIM;
+                writew(uap->im, uap->port.membase + UART011_IMSC);
+                return true;
+        }
+
+        /*
+         * We don't have a TX buffer queued, so try to queue one.
+         * If we succesfully queued a buffer, mask the TX IRQ.
+         */
+        if (pl011_dma_tx_refill(uap) > 0) {
+                uap->im &= ~UART011_TXIM;
+                writew(uap->im, uap->port.membase + UART011_IMSC);
+                return true;
+        }
+        return false;
+}
+
+/*
+ * Stop the DMA transmit (eg, due to received XOFF).
+ * Locking: called with port lock held and IRQs disabled.
+ */
+static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
+{
+        if (uap->dmatx.queued) {
+                uap->dmacr &= ~UART011_TXDMAE;
+                writew(uap->dmacr, uap->port.membase + UART011_DMACR);
+        }
+}
+
+/*
+ * Try to start a DMA transmit, or in the case of an XON/OFF
+ * character queued for send, try to get that character out ASAP.
+ * Locking: called with port lock held and IRQs disabled.
+ * Returns:
+ *   false if we want the TX IRQ to be enabled
+ *   true if we have a buffer queued
+ */
+static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
+{
+        u16 dmacr;
+
+        if (!uap->using_dma)
+                return false;
+
+        if (!uap->port.x_char) {
+                /* no X-char, try to push chars out in DMA mode */
+                bool ret = true;
+
+                if (!uap->dmatx.queued) {
+                        if (pl011_dma_tx_refill(uap) > 0) {
+                                uap->im &= ~UART011_TXIM;
+                                ret = true;
+                        } else {
+                                uap->im |= UART011_TXIM;
+                                ret = false;
+                        }
+                        writew(uap->im, uap->port.membase + UART011_IMSC);
+                } else if (!(uap->dmacr & UART011_TXDMAE)) {
+                        uap->dmacr |= UART011_TXDMAE;
+                        writew(uap->dmacr,
+                                       uap->port.membase + UART011_DMACR);
+                }
+                return ret;
+        }
+
+        /*
+         * We have an X-char to send.  Disable DMA to prevent it loading
+         * the TX fifo, and then see if we can stuff it into the FIFO.
+         */
+        dmacr = uap->dmacr;
+        uap->dmacr &= ~UART011_TXDMAE;
+        writew(uap->dmacr, uap->port.membase + UART011_DMACR);
+
+        if (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF) {
+                /*
+                 * No space in the FIFO, so enable the transmit interrupt
+                 * so we know when there is space.  Note that once we've
+                 * loaded the character, we should just re-enable DMA.
+                 */
+                return false;
+        }
+
+        writew(uap->port.x_char, uap->port.membase + UART01x_DR);
+        uap->port.icount.tx++;
+        uap->port.x_char = 0;
+
+        /* Success - restore the DMA state */
+        uap->dmacr = dmacr;
+        writew(dmacr, uap->port.membase + UART011_DMACR);
+
+        return true;
+}
+
+/*
+ * Flush the transmit buffer.
+ * Locking: called with port lock held and IRQs disabled.
+ */
+static void pl011_dma_flush_buffer(struct uart_port *port)
+{
+        struct uart_amba_port *uap = (struct uart_amba_port *)port;
+
+        if (!uap->using_dma)
+                return;
+
+        /* Avoid deadlock with the DMA engine callback */
+        spin_unlock(&uap->port.lock);
+        dmaengine_terminate_all(uap->dmatx.chan);
+        spin_lock(&uap->port.lock);
+        if (uap->dmatx.queued) {
+                dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
+                             DMA_TO_DEVICE);
+                uap->dmatx.queued = false;
+                uap->dmacr &= ~UART011_TXDMAE;
+                writew(uap->dmacr, uap->port.membase + UART011_DMACR);
+        }
+}
+
+
+static void pl011_dma_startup(struct uart_amba_port *uap)
+{
+        if (!uap->dmatx.chan)
+                return;
+
+        uap->dmatx.buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL);
+        if (!uap->dmatx.buf) {
+                dev_err(uap->port.dev, "no memory for DMA TX buffer\n");
+                uap->port.fifosize = uap->fifosize;
+                return;
+        }
+
+        sg_init_one(&uap->dmatx.sg, uap->dmatx.buf, PL011_DMA_BUFFER_SIZE);
+
+        /* The DMA buffer is now the FIFO the TTY subsystem can use */
+        uap->port.fifosize = PL011_DMA_BUFFER_SIZE;
+        uap->using_dma = true;
+
+        /* Turn on DMA error (RX/TX will be enabled on demand) */
+        uap->dmacr |= UART011_DMAONERR;
+        writew(uap->dmacr, uap->port.membase + UART011_DMACR);
+
+        /*
+         * ST Micro variants has some specific dma burst threshold
+         * compensation. Set this to 16 bytes, so burst will only
+         * be issued above/below 16 bytes.
+         */
+        if (uap->vendor->dma_threshold)
+                writew(ST_UART011_DMAWM_RX_16 | ST_UART011_DMAWM_TX_16,
+                               uap->port.membase + ST_UART011_DMAWM);
+}
+
+static void pl011_dma_shutdown(struct uart_amba_port *uap)
+{
+        if (!uap->using_dma)
+                return;
+
+        /* Disable RX and TX DMA */
+        while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY)
+                barrier();
+
+        spin_lock_irq(&uap->port.lock);
+        uap->dmacr &= ~(UART011_DMAONERR | UART011_RXDMAE | UART011_TXDMAE);
+        writew(uap->dmacr, uap->port.membase + UART011_DMACR);
+        spin_unlock_irq(&uap->port.lock);
+
+        /* In theory, this should already be done by pl011_dma_flush_buffer */
+        dmaengine_terminate_all(uap->dmatx.chan);
+        if (uap->dmatx.queued) {
+                dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
+                             DMA_TO_DEVICE);
+                uap->dmatx.queued = false;
+        }
+
+        kfree(uap->dmatx.buf);
+
+        uap->using_dma = false;
+}
+
+#else
+/* Blank functions if the DMA engine is not available */
+static inline void pl011_dma_probe(struct uart_amba_port *uap)
+{
+}
+
+static inline void pl011_dma_remove(struct uart_amba_port *uap)
+{
+}
+
+static inline void pl011_dma_startup(struct uart_amba_port *uap)
+{
+}
+
+static inline void pl011_dma_shutdown(struct uart_amba_port *uap)
+{
+}
+
+static inline bool pl011_dma_tx_irq(struct uart_amba_port *uap)
+{
+        return false;
+}
+
+static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
+{
+}
+
+static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
+{
+        return false;
+}
+
+#define pl011_dma_flush_buffer  NULL
+#endif
+
+
 static void pl011_stop_tx(struct uart_port *port)
 {
         struct uart_amba_port *uap = (struct uart_amba_port *)port;
 
         uap->im &= ~UART011_TXIM;
         writew(uap->im, uap->port.membase + UART011_IMSC);
+        pl011_dma_tx_stop(uap);
 }
 
 static void pl011_start_tx(struct uart_port *port)
 {
         struct uart_amba_port *uap = (struct uart_amba_port *)port;
 
-        uap->im |= UART011_TXIM;
-        writew(uap->im, uap->port.membase + UART011_IMSC);
+        if (!pl011_dma_tx_start(uap)) {
+                uap->im |= UART011_TXIM;
+                writew(uap->im, uap->port.membase + UART011_IMSC);
+        }
 }
 
 static void pl011_stop_rx(struct uart_port *port)
@@ -203,7 +707,11 @@ static void pl011_tx_chars(struct uart_amba_port *uap)
                 return;
         }
 
-        count = uap->port.fifosize >> 1;
+        /* If we are using DMA mode, try to send some characters. */
+        if (pl011_dma_tx_irq(uap))
+                return;
+
+        count = uap->fifosize >> 1;
         do {
                 writew(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR);
                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
@@ -246,10 +754,11 @@ static void pl011_modem_status(struct uart_amba_port *uap)
 static irqreturn_t pl011_int(int irq, void *dev_id)
 {
         struct uart_amba_port *uap = dev_id;
+        unsigned long flags;
         unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
         int handled = 0;
 
-        spin_lock(&uap->port.lock);
+        spin_lock_irqsave(&uap->port.lock, flags);
 
         status = readw(uap->port.membase + UART011_MIS);
         if (status) {
@@ -274,7 +783,7 @@ static irqreturn_t pl011_int(int irq, void *dev_id)
                 handled = 1;
         }
 
-        spin_unlock(&uap->port.lock);
+        spin_unlock_irqrestore(&uap->port.lock, flags);
 
         return IRQ_RETVAL(handled);
 }
@@ -396,7 +905,7 @@ static int pl011_startup(struct uart_port *port)
         if (retval)
                 goto clk_dis;
 
-        writew(uap->ifls, uap->port.membase + UART011_IFLS);
+        writew(uap->vendor->ifls, uap->port.membase + UART011_IFLS);
 
         /*
          * Provoke TX FIFO interrupt into asserting.
@@ -423,11 +932,18 @@ static int pl011_startup(struct uart_port *port)
         cr = UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
         writew(cr, uap->port.membase + UART011_CR);
 
+        /* Clear pending error interrupts */
+        writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS,
+               uap->port.membase + UART011_ICR);
+
         /*
          * initialise the old status of the modem signals
          */
         uap->old_status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
 
+        /* Startup DMA */
+        pl011_dma_startup(uap);
+
         /*
          * Finally, enable interrupts
          */
@@ -467,6 +983,8 @@ static void pl011_shutdown(struct uart_port *port)
         writew(0xffff, uap->port.membase + UART011_ICR);
         spin_unlock_irq(&uap->port.lock);
 
+        pl011_dma_shutdown(uap);
+
         /*
          * Free the interrupt
          */
@@ -498,13 +1016,18 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios,
         struct uart_amba_port *uap = (struct uart_amba_port *)port;
         unsigned int lcr_h, old_cr;
         unsigned long flags;
-        unsigned int baud, quot;
+        unsigned int baud, quot, clkdiv;
+
+        if (uap->vendor->oversampling)
+                clkdiv = 8;
+        else
+                clkdiv = 16;
 
         /*
          * Ask the core to calculate the divisor for us.
          */
         baud = uart_get_baud_rate(port, termios, old, 0,
-                                  port->uartclk/(uap->oversampling ? 8 : 16));
+                                  port->uartclk / clkdiv);
 
         if (baud > port->uartclk/16)
                 quot = DIV_ROUND_CLOSEST(port->uartclk * 8, baud);
@@ -532,7 +1055,7 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios,
                 if (!(termios->c_cflag & PARODD))
                         lcr_h |= UART01x_LCRH_EPS;
         }
-        if (port->fifosize > 1)
+        if (uap->fifosize > 1)
                 lcr_h |= UART01x_LCRH_FEN;
 
         spin_lock_irqsave(&port->lock, flags);
@@ -588,8 +1111,8 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios,
                 uap->autorts = false;
         }
 
-        if (uap->oversampling) {
-                if (baud > port->uartclk/16)
+        if (uap->vendor->oversampling) {
+                if (baud > port->uartclk / 16)
                         old_cr |= ST_UART011_CR_OVSFACT;
                 else
                         old_cr &= ~ST_UART011_CR_OVSFACT;
@@ -622,7 +1145,8 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios,
 
 static const char *pl011_type(struct uart_port *port)
 {
-        return port->type == PORT_AMBA ? "AMBA/PL011" : NULL;
+        struct uart_amba_port *uap = (struct uart_amba_port *)port;
+        return uap->port.type == PORT_AMBA ? uap->type : NULL;
 }
 
 /*
@@ -679,6 +1203,7 @@ static struct uart_ops amba_pl011_pops = {
         .break_ctl      = pl011_break_ctl,
         .startup        = pl011_startup,
         .shutdown       = pl011_shutdown,
+        .flush_buffer   = pl011_dma_flush_buffer,
         .set_termios    = pl011_set_termios,
         .type           = pl011_type,
         .release_port   = pl010_release_port,
@@ -761,7 +1286,7 @@ pl011_console_get_options(struct uart_amba_port *uap, int *baud,
 
                 *baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd);
 
-                if (uap->oversampling) {
+                if (uap->vendor->oversampling) {
                         if (readw(uap->port.membase + UART011_CR)
                                   & ST_UART011_CR_OVSFACT)
                                 *baud *= 2;
@@ -858,19 +1383,22 @@ static int pl011_probe(struct amba_device *dev, struct amba_id *id)
                 goto unmap;
         }
 
-        uap->ifls = vendor->ifls;
+        uap->vendor = vendor;
         uap->lcrh_rx = vendor->lcrh_rx;
         uap->lcrh_tx = vendor->lcrh_tx;
-        uap->oversampling = vendor->oversampling;
+        uap->fifosize = vendor->fifosize;
         uap->port.dev = &dev->dev;
         uap->port.mapbase = dev->res.start;
         uap->port.membase = base;
         uap->port.iotype = UPIO_MEM;
         uap->port.irq = dev->irq[0];
-        uap->port.fifosize = vendor->fifosize;
+        uap->port.fifosize = uap->fifosize;
         uap->port.ops = &amba_pl011_pops;
         uap->port.flags = UPF_BOOT_AUTOCONF;
         uap->port.line = i;
+        pl011_dma_probe(uap);
+
+        snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev));
 
         amba_ports[i] = uap;
 
@@ -879,6 +1407,7 @@ static int pl011_probe(struct amba_device *dev, struct amba_id *id)
         if (ret) {
                 amba_set_drvdata(dev, NULL);
                 amba_ports[i] = NULL;
+                pl011_dma_remove(uap);
                 clk_put(uap->clk);
  unmap:
                 iounmap(base);
@@ -902,6 +1431,7 @@ static int pl011_remove(struct amba_device *dev)
                 if (amba_ports[i] == uap)
                         amba_ports[i] = NULL;
 
+        pl011_dma_remove(uap);
         iounmap(uap->port.membase);
         clk_put(uap->clk);
         kfree(uap);
diff --git a/drivers/serial/apbuart.c b/drivers/serial/apbuart.c
index cc01c650a144..767ce9e396c5 100644
--- a/drivers/serial/apbuart.c
+++ b/drivers/serial/apbuart.c
@@ -26,6 +26,7 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/of_platform.h>
+#include <linux/of_irq.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/serial_core.h>
@@ -573,13 +574,15 @@ static int __devinit apbuart_probe(struct platform_device *op,
         printk(KERN_INFO "grlib-apbuart at 0x%llx, irq %d\n",
                (unsigned long long) port->mapbase, port->irq);
         return 0;
-
 }
 
 static struct of_device_id __initdata apbuart_match[] = {
         {
          .name = "GAISLER_APBUART",
          },
+        {
+         .name = "01_00c",
+         },
         {},
 };
 
@@ -620,9 +623,12 @@ static void grlib_apbuart_configure(void)
                 int *vendor = (int *) of_get_property(np, "vendor", NULL);
                 int *device = (int *) of_get_property(np, "device", NULL);
                 int *irqs = (int *) of_get_property(np, "interrupts", NULL);
+                int *ampopts = (int *) of_get_property(np, "ampopts", NULL);
                 regs = (struct amba_prom_registers *)
                     of_get_property(np, "reg", NULL);
 
+                if (ampopts && (*ampopts == 0))
+                        continue; /* Ignore if used by another OS instance */
                 if (vendor)
                         v = *vendor;
                 if (device)
diff --git a/drivers/serial/msm_serial.c b/drivers/serial/msm_serial.c
index f8c816e7725d..8e43a7b69e64 100644
--- a/drivers/serial/msm_serial.c
+++ b/drivers/serial/msm_serial.c
@@ -686,7 +686,7 @@ static int __init msm_serial_probe(struct platform_device *pdev)
         msm_port = UART_TO_MSM(port);
 
         msm_port->clk = clk_get(&pdev->dev, "uart_clk");
-        if (unlikely(IS_ERR(msm_port->clk)))
+        if (IS_ERR(msm_port->clk))
                 return PTR_ERR(msm_port->clk);
         port->uartclk = clk_get_rate(msm_port->clk);
         printk(KERN_INFO "uartclk = %d\n", port->uartclk);