#define UARTWATER_TXWATER_OFF 0
#define UARTWATER_RXWATER_OFF 16
-#define FSL_UART_RX_DMA_BUFFER_SIZE 64
+/* Rx DMA timeout in ms, which is used to calculate Rx ring buffer size */
+#define DMA_RX_TIMEOUT (10)
#define DRIVER_NAME "fsl-lpuart"
#define DEV_NAME "ttyLP"
struct dma_async_tx_descriptor *dma_tx_desc;
struct dma_async_tx_descriptor *dma_rx_desc;
dma_addr_t dma_tx_buf_bus;
- dma_addr_t dma_rx_buf_bus;
dma_cookie_t dma_tx_cookie;
dma_cookie_t dma_rx_cookie;
unsigned char *dma_tx_buf_virt;
- unsigned char *dma_rx_buf_virt;
unsigned int dma_tx_bytes;
unsigned int dma_rx_bytes;
int dma_tx_in_progress;
- int dma_rx_in_progress;
unsigned int dma_rx_timeout;
struct timer_list lpuart_timer;
+ struct scatterlist rx_sgl;
+ struct circ_buf rx_ring;
+ int rx_dma_rng_buf_len;
};
static const struct of_device_id lpuart_dt_ids[] = {
/* Forward declare this for the dma callbacks*/
static void lpuart_dma_tx_complete(void *arg);
-static void lpuart_dma_rx_complete(void *arg);
static u32 lpuart32_read(void __iomem *addr)
{
lpuart32_write(temp & ~UARTCTRL_RE, port->membase + UARTCTRL);
}
-static void lpuart_copy_rx_to_tty(struct lpuart_port *sport,
- struct tty_port *tty, int count)
-{
- int copied;
-
- sport->port.icount.rx += count;
-
- if (!tty) {
- dev_err(sport->port.dev, "No tty port\n");
- return;
- }
-
- dma_sync_single_for_cpu(sport->port.dev, sport->dma_rx_buf_bus,
- FSL_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
- copied = tty_insert_flip_string(tty,
- ((unsigned char *)(sport->dma_rx_buf_virt)), count);
-
- if (copied != count) {
- WARN_ON(1);
- dev_err(sport->port.dev, "RxData copy to tty layer failed\n");
- }
-
- dma_sync_single_for_device(sport->port.dev, sport->dma_rx_buf_bus,
- FSL_UART_RX_DMA_BUFFER_SIZE, DMA_TO_DEVICE);
-}
-
static void lpuart_pio_tx(struct lpuart_port *sport)
{
struct circ_buf *xmit = &sport->port.state->xmit;
spin_unlock_irqrestore(&sport->port.lock, flags);
}
-static int lpuart_dma_rx(struct lpuart_port *sport)
-{
- dma_sync_single_for_device(sport->port.dev, sport->dma_rx_buf_bus,
- FSL_UART_RX_DMA_BUFFER_SIZE, DMA_TO_DEVICE);
- sport->dma_rx_desc = dmaengine_prep_slave_single(sport->dma_rx_chan,
- sport->dma_rx_buf_bus, FSL_UART_RX_DMA_BUFFER_SIZE,
- DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
-
- if (!sport->dma_rx_desc) {
- dev_err(sport->port.dev, "Not able to get desc for rx\n");
- return -EIO;
- }
-
- sport->dma_rx_desc->callback = lpuart_dma_rx_complete;
- sport->dma_rx_desc->callback_param = sport;
- sport->dma_rx_in_progress = 1;
- sport->dma_rx_cookie = dmaengine_submit(sport->dma_rx_desc);
- dma_async_issue_pending(sport->dma_rx_chan);
-
- return 0;
-}
-
static void lpuart_flush_buffer(struct uart_port *port)
{
struct lpuart_port *sport = container_of(port, struct lpuart_port, port);
}
}
-static void lpuart_dma_rx_complete(void *arg)
-{
- struct lpuart_port *sport = arg;
- struct tty_port *port = &sport->port.state->port;
- unsigned long flags;
-
- async_tx_ack(sport->dma_rx_desc);
- mod_timer(&sport->lpuart_timer, jiffies + sport->dma_rx_timeout);
-
- spin_lock_irqsave(&sport->port.lock, flags);
-
- sport->dma_rx_in_progress = 0;
- lpuart_copy_rx_to_tty(sport, port, FSL_UART_RX_DMA_BUFFER_SIZE);
- tty_flip_buffer_push(port);
- lpuart_dma_rx(sport);
-
- spin_unlock_irqrestore(&sport->port.lock, flags);
-}
-
-static void lpuart_dma_rx_terminate(struct lpuart_port *sport)
-{
- struct tty_port *port = &sport->port.state->port;
- struct dma_tx_state state;
- unsigned long flags;
- unsigned char temp;
- int count;
-
- del_timer(&sport->lpuart_timer);
- dmaengine_pause(sport->dma_rx_chan);
- dmaengine_tx_status(sport->dma_rx_chan, sport->dma_rx_cookie, &state);
- dmaengine_terminate_all(sport->dma_rx_chan);
- count = FSL_UART_RX_DMA_BUFFER_SIZE - state.residue;
- async_tx_ack(sport->dma_rx_desc);
-
- spin_lock_irqsave(&sport->port.lock, flags);
-
- sport->dma_rx_in_progress = 0;
- lpuart_copy_rx_to_tty(sport, port, count);
- tty_flip_buffer_push(port);
- temp = readb(sport->port.membase + UARTCR5);
- writeb(temp & ~UARTCR5_RDMAS, sport->port.membase + UARTCR5);
-
- spin_unlock_irqrestore(&sport->port.lock, flags);
-}
-
-static void lpuart_timer_func(unsigned long data)
-{
- lpuart_dma_rx_terminate((struct lpuart_port *)data);
-}
-
-static inline void lpuart_prepare_rx(struct lpuart_port *sport)
-{
- unsigned long flags;
- unsigned char temp;
-
- spin_lock_irqsave(&sport->port.lock, flags);
-
- sport->lpuart_timer.expires = jiffies + sport->dma_rx_timeout;
- add_timer(&sport->lpuart_timer);
-
- lpuart_dma_rx(sport);
- temp = readb(sport->port.membase + UARTCR5);
- writeb(temp | UARTCR5_RDMAS, sport->port.membase + UARTCR5);
-
- spin_unlock_irqrestore(&sport->port.lock, flags);
-}
-
static inline void lpuart_transmit_buffer(struct lpuart_port *sport)
{
struct circ_buf *xmit = &sport->port.state->xmit;
static irqreturn_t lpuart_int(int irq, void *dev_id)
{
struct lpuart_port *sport = dev_id;
- unsigned char sts, crdma;
+ unsigned char sts;
sts = readb(sport->port.membase + UARTSR1);
- crdma = readb(sport->port.membase + UARTCR5);
- if (sts & UARTSR1_RDRF && !(crdma & UARTCR5_RDMAS)) {
- if (sport->lpuart_dma_rx_use)
- lpuart_prepare_rx(sport);
- else
- lpuart_rxint(irq, dev_id);
- }
- if (sts & UARTSR1_TDRE && !(crdma & UARTCR5_TDMAS)) {
+ if (sts & UARTSR1_RDRF)
+ lpuart_rxint(irq, dev_id);
+
+ if (sts & UARTSR1_TDRE) {
if (sport->lpuart_dma_tx_use)
lpuart_pio_tx(sport);
else
TIOCSER_TEMT : 0;
}
+static void lpuart_copy_rx_to_tty(struct lpuart_port *sport)
+{
+ struct tty_port *port = &sport->port.state->port;
+ struct dma_tx_state state;
+ enum dma_status dmastat;
+ struct circ_buf *ring = &sport->rx_ring;
+ unsigned long flags;
+ int count = 0;
+ unsigned char sr;
+
+ sr = readb(sport->port.membase + UARTSR1);
+
+ if (sr & (UARTSR1_PE | UARTSR1_FE)) {
+ /* Read DR to clear the error flags */
+ readb(sport->port.membase + UARTDR);
+
+ if (sr & UARTSR1_PE)
+ sport->port.icount.parity++;
+ else if (sr & UARTSR1_FE)
+ sport->port.icount.frame++;
+ }
+
+ async_tx_ack(sport->dma_rx_desc);
+
+ spin_lock_irqsave(&sport->port.lock, flags);
+
+ dmastat = dmaengine_tx_status(sport->dma_rx_chan,
+ sport->dma_rx_cookie,
+ &state);
+
+ if (dmastat == DMA_ERROR) {
+ dev_err(sport->port.dev, "Rx DMA transfer failed!\n");
+ spin_unlock_irqrestore(&sport->port.lock, flags);
+ return;
+ }
+
+ /* CPU claims ownership of RX DMA buffer */
+ dma_sync_sg_for_cpu(sport->port.dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);
+
+ /*
+ * ring->head points to the end of data already written by the DMA.
+ * ring->tail points to the beginning of data to be read by the
+ * framework.
+ * The current transfer size should not be larger than the dma buffer
+ * length.
+ */
+ ring->head = sport->rx_sgl.length - state.residue;
+ BUG_ON(ring->head > sport->rx_sgl.length);
+ /*
+ * At this point ring->head may point to the first byte right after the
+ * last byte of the dma buffer:
+ * 0 <= ring->head <= sport->rx_sgl.length
+ *
+ * However ring->tail must always points inside the dma buffer:
+ * 0 <= ring->tail <= sport->rx_sgl.length - 1
+ *
+ * Since we use a ring buffer, we have to handle the case
+ * where head is lower than tail. In such a case, we first read from
+ * tail to the end of the buffer then reset tail.
+ */
+ if (ring->head < ring->tail) {
+ count = sport->rx_sgl.length - ring->tail;
+
+ tty_insert_flip_string(port, ring->buf + ring->tail, count);
+ ring->tail = 0;
+ sport->port.icount.rx += count;
+ }
+
+ /* Finally we read data from tail to head */
+ if (ring->tail < ring->head) {
+ count = ring->head - ring->tail;
+ tty_insert_flip_string(port, ring->buf + ring->tail, count);
+ /* Wrap ring->head if needed */
+ if (ring->head >= sport->rx_sgl.length)
+ ring->head = 0;
+ ring->tail = ring->head;
+ sport->port.icount.rx += count;
+ }
+
+ dma_sync_sg_for_device(sport->port.dev, &sport->rx_sgl, 1,
+ DMA_FROM_DEVICE);
+
+ spin_unlock_irqrestore(&sport->port.lock, flags);
+
+ tty_flip_buffer_push(port);
+ mod_timer(&sport->lpuart_timer, jiffies + sport->dma_rx_timeout);
+}
+
+static void lpuart_dma_rx_complete(void *arg)
+{
+ struct lpuart_port *sport = arg;
+
+ lpuart_copy_rx_to_tty(sport);
+}
+
+static void lpuart_timer_func(unsigned long data)
+{
+ struct lpuart_port *sport = (struct lpuart_port *)data;
+
+ lpuart_copy_rx_to_tty(sport);
+}
+
+static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
+{
+ struct dma_slave_config dma_rx_sconfig = {};
+ struct circ_buf *ring = &sport->rx_ring;
+ int ret, nent;
+ int bits, baud;
+ struct tty_struct *tty = tty_port_tty_get(&sport->port.state->port);
+ struct ktermios *termios = &tty->termios;
+
+ baud = tty_get_baud_rate(tty);
+
+ bits = (termios->c_cflag & CSIZE) == CS7 ? 9 : 10;
+ if (termios->c_cflag & PARENB)
+ bits++;
+
+ /*
+ * Calculate length of one DMA buffer size to keep latency below
+ * 10ms at any baud rate.
+ */
+ sport->rx_dma_rng_buf_len = (DMA_RX_TIMEOUT * baud / bits / 1000) * 2;
+ sport->rx_dma_rng_buf_len = (1 << (fls(sport->rx_dma_rng_buf_len) - 1));
+ if (sport->rx_dma_rng_buf_len < 16)
+ sport->rx_dma_rng_buf_len = 16;
+
+ ring->buf = kmalloc(sport->rx_dma_rng_buf_len, GFP_KERNEL);
+ if (!ring->buf) {
+ dev_err(sport->port.dev, "Ring buf alloc failed\n");
+ return -ENOMEM;
+ }
+
+ sg_init_one(&sport->rx_sgl, ring->buf, sport->rx_dma_rng_buf_len);
+ sg_set_buf(&sport->rx_sgl, ring->buf, sport->rx_dma_rng_buf_len);
+ nent = dma_map_sg(sport->port.dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);
+
+ if (!nent) {
+ dev_err(sport->port.dev, "DMA Rx mapping error\n");
+ return -EINVAL;
+ }
+
+ dma_rx_sconfig.src_addr = sport->port.mapbase + UARTDR;
+ dma_rx_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ dma_rx_sconfig.src_maxburst = 1;
+ dma_rx_sconfig.direction = DMA_DEV_TO_MEM;
+ ret = dmaengine_slave_config(sport->dma_rx_chan, &dma_rx_sconfig);
+
+ if (ret < 0) {
+ dev_err(sport->port.dev,
+ "DMA Rx slave config failed, err = %d\n", ret);
+ return ret;
+ }
+
+ sport->dma_rx_desc = dmaengine_prep_dma_cyclic(sport->dma_rx_chan,
+ sg_dma_address(&sport->rx_sgl),
+ sport->rx_sgl.length,
+ sport->rx_sgl.length / 2,
+ DMA_DEV_TO_MEM,
+ DMA_PREP_INTERRUPT);
+ if (!sport->dma_rx_desc) {
+ dev_err(sport->port.dev, "Cannot prepare cyclic DMA\n");
+ return -EFAULT;
+ }
+
+ sport->dma_rx_desc->callback = lpuart_dma_rx_complete;
+ sport->dma_rx_desc->callback_param = sport;
+ sport->dma_rx_cookie = dmaengine_submit(sport->dma_rx_desc);
+ dma_async_issue_pending(sport->dma_rx_chan);
+
+ writeb(readb(sport->port.membase + UARTCR5) | UARTCR5_RDMAS,
+ sport->port.membase + UARTCR5);
+
+ return 0;
+}
+
+static void lpuart_dma_tx_free(struct uart_port *port)
+{
+ struct lpuart_port *sport = container_of(port,
+ struct lpuart_port, port);
+
+ dma_unmap_single(sport->port.dev, sport->dma_tx_buf_bus,
+ UART_XMIT_SIZE, DMA_TO_DEVICE);
+
+ sport->dma_tx_buf_bus = 0;
+ sport->dma_tx_buf_virt = NULL;
+}
+
+static void lpuart_dma_rx_free(struct uart_port *port)
+{
+ struct lpuart_port *sport = container_of(port,
+ struct lpuart_port, port);
+
+ if (sport->dma_rx_chan)
+ dmaengine_terminate_all(sport->dma_rx_chan);
+
+ dma_unmap_sg(sport->port.dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);
+ kfree(sport->rx_ring.buf);
+ sport->rx_ring.tail = 0;
+ sport->rx_ring.head = 0;
+ sport->dma_rx_desc = NULL;
+ sport->dma_rx_cookie = -EINVAL;
+}
+
static unsigned int lpuart_get_mctrl(struct uart_port *port)
{
unsigned int temp = 0;
return 0;
}
-static int lpuart_dma_rx_request(struct uart_port *port)
+static void rx_dma_timer_init(struct lpuart_port *sport)
{
- struct lpuart_port *sport = container_of(port,
- struct lpuart_port, port);
- struct dma_slave_config dma_rx_sconfig;
- dma_addr_t dma_bus;
- unsigned char *dma_buf;
- int ret;
-
- dma_buf = devm_kzalloc(sport->port.dev,
- FSL_UART_RX_DMA_BUFFER_SIZE, GFP_KERNEL);
-
- if (!dma_buf) {
- dev_err(sport->port.dev, "Dma rx alloc failed\n");
- return -ENOMEM;
- }
-
- dma_bus = dma_map_single(sport->dma_rx_chan->device->dev, dma_buf,
- FSL_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
-
- if (dma_mapping_error(sport->dma_rx_chan->device->dev, dma_bus)) {
- dev_err(sport->port.dev, "dma_map_single rx failed\n");
- return -ENOMEM;
- }
-
- dma_rx_sconfig.src_addr = sport->port.mapbase + UARTDR;
- dma_rx_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
- dma_rx_sconfig.src_maxburst = 1;
- dma_rx_sconfig.direction = DMA_DEV_TO_MEM;
- ret = dmaengine_slave_config(sport->dma_rx_chan, &dma_rx_sconfig);
-
- if (ret < 0) {
- dev_err(sport->port.dev,
- "Dma slave config failed, err = %d\n", ret);
- return ret;
- }
-
- sport->dma_rx_buf_virt = dma_buf;
- sport->dma_rx_buf_bus = dma_bus;
- sport->dma_rx_in_progress = 0;
-
- return 0;
-}
-
-static void lpuart_dma_tx_free(struct uart_port *port)
-{
- struct lpuart_port *sport = container_of(port,
- struct lpuart_port, port);
-
- dma_unmap_single(sport->port.dev, sport->dma_tx_buf_bus,
- UART_XMIT_SIZE, DMA_TO_DEVICE);
-
- sport->dma_tx_buf_bus = 0;
- sport->dma_tx_buf_virt = NULL;
-}
-
-static void lpuart_dma_rx_free(struct uart_port *port)
-{
- struct lpuart_port *sport = container_of(port,
- struct lpuart_port, port);
-
- dma_unmap_single(sport->port.dev, sport->dma_rx_buf_bus,
- FSL_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
-
- sport->dma_rx_buf_bus = 0;
- sport->dma_rx_buf_virt = NULL;
+ setup_timer(&sport->lpuart_timer, lpuart_timer_func,
+ (unsigned long)sport);
+ sport->lpuart_timer.expires = jiffies + sport->dma_rx_timeout;
+ add_timer(&sport->lpuart_timer);
}
static int lpuart_startup(struct uart_port *port)
sport->rxfifo_size = 0x1 << (((temp >> UARTPFIFO_RXSIZE_OFF) &
UARTPFIFO_FIFOSIZE_MASK) + 1);
- if (sport->dma_rx_chan && !lpuart_dma_rx_request(port)) {
- sport->lpuart_dma_rx_use = true;
- setup_timer(&sport->lpuart_timer, lpuart_timer_func,
- (unsigned long)sport);
- } else
- sport->lpuart_dma_rx_use = false;
-
-
- if (sport->dma_tx_chan && !lpuart_dma_tx_request(port)) {
- sport->lpuart_dma_tx_use = true;
- temp = readb(port->membase + UARTCR5);
- temp &= ~UARTCR5_RDMAS;
- writeb(temp | UARTCR5_TDMAS, port->membase + UARTCR5);
- } else
- sport->lpuart_dma_tx_use = false;
-
ret = devm_request_irq(port->dev, port->irq, lpuart_int, 0,
DRIVER_NAME, sport);
if (ret)
temp |= (UARTCR2_RIE | UARTCR2_TIE | UARTCR2_RE | UARTCR2_TE);
writeb(temp, sport->port.membase + UARTCR2);
+ if (sport->dma_rx_chan && !lpuart_start_rx_dma(sport)) {
+ /* set Rx DMA timeout */
+ sport->dma_rx_timeout = msecs_to_jiffies(DMA_RX_TIMEOUT);
+ if (!sport->dma_rx_timeout)
+ sport->dma_rx_timeout = 1;
+
+ sport->lpuart_dma_rx_use = true;
+ rx_dma_timer_init(sport);
+ } else {
+ sport->lpuart_dma_rx_use = false;
+ }
+
+ if (sport->dma_tx_chan && !lpuart_dma_tx_request(port)) {
+ sport->lpuart_dma_tx_use = true;
+ temp = readb(port->membase + UARTCR5);
+ writeb(temp | UARTCR5_TDMAS, port->membase + UARTCR5);
+ } else {
+ sport->lpuart_dma_tx_use = false;
+ }
+
spin_unlock_irqrestore(&sport->port.lock, flags);
+
return 0;
}
devm_free_irq(port->dev, port->irq, sport);
if (sport->lpuart_dma_rx_use) {
- lpuart_dma_rx_free(&sport->port);
del_timer_sync(&sport->lpuart_timer);
+ lpuart_dma_rx_free(&sport->port);
}
if (sport->lpuart_dma_tx_use)
/* update the per-port timeout */
uart_update_timeout(port, termios->c_cflag, baud);
- if (sport->lpuart_dma_rx_use) {
- /* Calculate delay for 1.5 DMA buffers */
- sport->dma_rx_timeout = (sport->port.timeout - HZ / 50) *
- FSL_UART_RX_DMA_BUFFER_SIZE * 3 /
- sport->rxfifo_size / 2;
- dev_dbg(port->dev, "DMA Rx t-out %ums, tty t-out %u jiffies\n",
- sport->dma_rx_timeout * 1000 / HZ, sport->port.timeout);
- if (sport->dma_rx_timeout < msecs_to_jiffies(20))
- sport->dma_rx_timeout = msecs_to_jiffies(20);
- }
-
/* wait transmit engin complete */
while (!(readb(sport->port.membase + UARTSR1) & UARTSR1_TC))
barrier();
/* restore control register */
writeb(old_cr2, sport->port.membase + UARTCR2);
+ /*
+ * If new baud rate is set, we will also need to update the Ring buffer
+ * length according to the selected baud rate and restart Rx DMA path.
+ */
+ if (old) {
+ if (sport->lpuart_dma_rx_use) {
+ del_timer_sync(&sport->lpuart_timer);
+ lpuart_dma_rx_free(&sport->port);
+ }
+
+ if (sport->dma_rx_chan && !lpuart_start_rx_dma(sport)) {
+ sport->lpuart_dma_rx_use = true;
+ rx_dma_timer_init(sport);
+ } else {
+ sport->lpuart_dma_rx_use = false;
+ }
+ }
+
spin_unlock_irqrestore(&sport->port.lock, flags);
}
writeb(temp, sport->port.membase + UARTCR2);
}
- if (sport->dma_rx_in_progress)
- lpuart_dma_rx_terminate(sport);
-
uart_suspend_port(&lpuart_reg, &sport->port);
if (sport->port.suspended && !sport->port.irq_wake)
clk_disable_unprepare(sport->clk);
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff