#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
+#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#define UARTDM_BURST_SIZE 16 /* in bytes */
#define UARTDM_TX_AIGN(x) ((x) & ~0x3) /* valid for > 1p3 */
#define UARTDM_TX_MAX 256 /* in bytes, valid for <= 1p3 */
+#define UARTDM_RX_SIZE (UART_XMIT_SIZE / 4)
enum {
UARTDM_1P1 = 1,
unsigned int old_snap_state;
bool break_detected;
struct msm_dma tx_dma;
+ struct msm_dma rx_dma;
};
static void msm_handle_tx(struct uart_port *port);
+static void msm_start_rx_dma(struct msm_port *msm_port);
void msm_stop_dma(struct uart_port *port, struct msm_dma *dma)
{
}
memset(dma, 0, sizeof(*dma));
+
+ dma = &msm_port->rx_dma;
+ if (dma->chan) {
+ msm_stop_dma(&msm_port->uart, dma);
+ dma_release_channel(dma->chan);
+ kfree(dma->virt);
+ }
+
+ memset(dma, 0, sizeof(*dma));
}
static void msm_request_tx_dma(struct msm_port *msm_port, resource_size_t base)
memset(dma, 0, sizeof(*dma));
}
+static void msm_request_rx_dma(struct msm_port *msm_port, resource_size_t base)
+{
+ struct device *dev = msm_port->uart.dev;
+ struct dma_slave_config conf;
+ struct msm_dma *dma;
+ u32 crci = 0;
+ int ret;
+
+ dma = &msm_port->rx_dma;
+
+ /* allocate DMA resources, if available */
+ dma->chan = dma_request_slave_channel_reason(dev, "rx");
+ if (IS_ERR(dma->chan))
+ goto no_rx;
+
+ of_property_read_u32(dev->of_node, "qcom,rx-crci", &crci);
+
+ dma->virt = kzalloc(UARTDM_RX_SIZE, GFP_KERNEL);
+ if (!dma->virt)
+ goto rel_rx;
+
+ memset(&conf, 0, sizeof(conf));
+ conf.direction = DMA_DEV_TO_MEM;
+ conf.device_fc = true;
+ conf.src_addr = base + UARTDM_RF;
+ conf.src_maxburst = UARTDM_BURST_SIZE;
+ conf.slave_id = crci;
+
+ ret = dmaengine_slave_config(dma->chan, &conf);
+ if (ret)
+ goto err;
+
+ dma->dir = DMA_FROM_DEVICE;
+
+ if (msm_port->is_uartdm < UARTDM_1P4)
+ dma->enable_bit = UARTDM_DMEN_RX_DM_ENABLE;
+ else
+ dma->enable_bit = UARTDM_DMEN_RX_BAM_ENABLE;
+
+ return;
+err:
+ kfree(dma->virt);
+rel_rx:
+ dma_release_channel(dma->chan);
+no_rx:
+ memset(dma, 0, sizeof(*dma));
+}
+
static inline void msm_wait_for_xmitr(struct uart_port *port)
{
while (!(msm_read(port, UART_SR) & UART_SR_TX_EMPTY)) {
dma_unmap_single(port->dev, dma->phys, count, dma->dir);
return ret;
}
+
+static void msm_complete_rx_dma(void *args)
+{
+ struct msm_port *msm_port = args;
+ struct uart_port *port = &msm_port->uart;
+ struct tty_port *tport = &port->state->port;
+ struct msm_dma *dma = &msm_port->rx_dma;
+ int count = 0, i, sysrq;
+ unsigned long flags;
+ u32 val;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ /* Already stopped */
+ if (!dma->count)
+ goto done;
+
+ val = msm_read(port, UARTDM_DMEN);
+ val &= ~dma->enable_bit;
+ msm_write(port, val, UARTDM_DMEN);
+
+ /* Restore interrupts */
+ msm_port->imr |= UART_IMR_RXLEV | UART_IMR_RXSTALE;
+ msm_write(port, msm_port->imr, UART_IMR);
+
+ if (msm_read(port, UART_SR) & UART_SR_OVERRUN) {
+ port->icount.overrun++;
+ tty_insert_flip_char(tport, 0, TTY_OVERRUN);
+ msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
+ }
+
+ count = msm_read(port, UARTDM_RX_TOTAL_SNAP);
+
+ port->icount.rx += count;
+
+ dma->count = 0;
+
+ dma_unmap_single(port->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
+
+ for (i = 0; i < count; i++) {
+ char flag = TTY_NORMAL;
+
+ if (msm_port->break_detected && dma->virt[i] == 0) {
+ port->icount.brk++;
+ flag = TTY_BREAK;
+ msm_port->break_detected = false;
+ if (uart_handle_break(port))
+ continue;
+ }
+
+ if (!(port->read_status_mask & UART_SR_RX_BREAK))
+ flag = TTY_NORMAL;
+
+ spin_unlock_irqrestore(&port->lock, flags);
+ sysrq = uart_handle_sysrq_char(port, dma->virt[i]);
+ spin_lock_irqsave(&port->lock, flags);
+ if (!sysrq)
+ tty_insert_flip_char(tport, dma->virt[i], flag);
+ }
+
+ msm_start_rx_dma(msm_port);
+done:
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ if (count)
+ tty_flip_buffer_push(tport);
+}
+
+static void msm_start_rx_dma(struct msm_port *msm_port)
+{
+ struct msm_dma *dma = &msm_port->rx_dma;
+ struct uart_port *uart = &msm_port->uart;
+ u32 val;
+ int ret;
+
+ if (!dma->chan)
+ return;
+
+ dma->phys = dma_map_single(uart->dev, dma->virt,
+ UARTDM_RX_SIZE, dma->dir);
+ ret = dma_mapping_error(uart->dev, dma->phys);
+ if (ret)
+ return;
+
+ dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
+ UARTDM_RX_SIZE, DMA_DEV_TO_MEM,
+ DMA_PREP_INTERRUPT);
+ if (!dma->desc)
+ goto unmap;
+
+ dma->desc->callback = msm_complete_rx_dma;
+ dma->desc->callback_param = msm_port;
+
+ dma->cookie = dmaengine_submit(dma->desc);
+ ret = dma_submit_error(dma->cookie);
+ if (ret)
+ goto unmap;
+ /*
+ * Using DMA for FIFO off-load, no need for "Rx FIFO over
+ * watermark" or "stale" interrupts, disable them
+ */
+ msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
+
+ /*
+ * Well, when DMA is ADM3 engine(implied by <= UARTDM v1.3),
+ * we need RXSTALE to flush input DMA fifo to memory
+ */
+ if (msm_port->is_uartdm < UARTDM_1P4)
+ msm_port->imr |= UART_IMR_RXSTALE;
+
+ msm_write(uart, msm_port->imr, UART_IMR);
+
+ dma->count = UARTDM_RX_SIZE;
+
+ dma_async_issue_pending(dma->chan);
+
+ msm_write(uart, UART_CR_CMD_RESET_STALE_INT, UART_CR);
+ msm_write(uart, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
+
+ val = msm_read(uart, UARTDM_DMEN);
+ val |= dma->enable_bit;
+
+ if (msm_port->is_uartdm < UARTDM_1P4)
+ msm_write(uart, val, UARTDM_DMEN);
+
+ msm_write(uart, UARTDM_RX_SIZE, UARTDM_DMRX);
+
+ if (msm_port->is_uartdm > UARTDM_1P3)
+ msm_write(uart, val, UARTDM_DMEN);
+
+ return;
+unmap:
+ dma_unmap_single(uart->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
+}
+
static void msm_stop_rx(struct uart_port *port)
{
struct msm_port *msm_port = UART_TO_MSM(port);
+ struct msm_dma *dma = &msm_port->rx_dma;
msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
msm_write(port, msm_port->imr, UART_IMR);
+
+ if (dma->chan)
+ msm_stop_dma(port, dma);
}
static void msm_enable_ms(struct uart_port *port)
msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
msm_write(port, 0xFFFFFF, UARTDM_DMRX);
msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
+
+ /* Try to use DMA */
+ msm_start_rx_dma(msm_port);
}
static void msm_handle_rx(struct uart_port *port)
{
struct uart_port *port = dev_id;
struct msm_port *msm_port = UART_TO_MSM(port);
+ struct msm_dma *dma = &msm_port->rx_dma;
unsigned long flags;
unsigned int misr;
+ u32 val;
spin_lock_irqsave(&port->lock, flags);
misr = msm_read(port, UART_MISR);
}
if (misr & (UART_IMR_RXLEV | UART_IMR_RXSTALE)) {
- if (msm_port->is_uartdm)
+ if (dma->count) {
+ val = UART_CR_CMD_STALE_EVENT_DISABLE;
+ msm_write(port, val, UART_CR);
+ val = UART_CR_CMD_RESET_STALE_INT;
+ msm_write(port, val, UART_CR);
+ /*
+ * Flush DMA input fifo to memory, this will also
+ * trigger DMA RX completion
+ */
+ dmaengine_terminate_all(dma->chan);
+ } else if (msm_port->is_uartdm) {
msm_handle_rx_dm(port, misr);
- else
+ } else {
msm_handle_rx(port);
+ }
}
if (misr & UART_IMR_TXLEV)
msm_handle_tx(port);
data |= UART_MR1_AUTO_RFR_LEVEL0 & rfr_level;
msm_write(port, data, UART_MR1);
- if (msm_port->is_uartdm)
+ if (msm_port->is_uartdm) {
msm_request_tx_dma(msm_port, msm_port->uart.mapbase);
+ msm_request_rx_dma(msm_port, msm_port->uart.mapbase);
+ }
return 0;
}
static void msm_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
{
+ struct msm_port *msm_port = UART_TO_MSM(port);
+ struct msm_dma *dma = &msm_port->rx_dma;
unsigned long flags;
unsigned int baud, mr;
spin_lock_irqsave(&port->lock, flags);
+ if (dma->chan) /* Terminate if any */
+ msm_stop_dma(port, dma);
+
/* calculate and set baud rate */
baud = uart_get_baud_rate(port, termios, old, 300, 115200);
baud = msm_set_baud_rate(port, baud);
uart_update_timeout(port, termios->c_cflag, baud);
+ /* Try to use DMA */
+ msm_start_rx_dma(msm_port);
+
spin_unlock_irqrestore(&port->lock, flags);
}
projects / linux-beck.git / commitdiff