diff options
Diffstat (limited to 'drivers/tty/serial/stm32-usart.c')
| -rw-r--r-- | drivers/tty/serial/stm32-usart.c | 80 |
1 files changed, 53 insertions, 27 deletions
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 4b5b0748790c..3244e7f6818c 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -210,11 +210,12 @@ static unsigned long stm32_usart_get_char_pio(struct uart_port *port) return c; } -static void stm32_usart_receive_chars_pio(struct uart_port *port) +static unsigned int stm32_usart_receive_chars_pio(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; unsigned long c; + unsigned int size = 0; u32 sr; char flag; @@ -239,6 +240,7 @@ static void stm32_usart_receive_chars_pio(struct uart_port *port) c = stm32_usart_get_char_pio(port); port->icount.rx++; + size++; if (sr & USART_SR_ERR_MASK) { if (sr & USART_SR_ORE) { port->icount.overrun++; @@ -271,6 +273,8 @@ static void stm32_usart_receive_chars_pio(struct uart_port *port) continue; uart_insert_char(port, sr, USART_SR_ORE, c, flag); } + + return size; } static void stm32_usart_push_buffer_dma(struct uart_port *port, unsigned int dma_size) @@ -300,50 +304,48 @@ static void stm32_usart_push_buffer_dma(struct uart_port *port, unsigned int dma stm32_port->last_res = RX_BUF_L; } -static void stm32_usart_receive_chars_dma(struct uart_port *port) +static unsigned int stm32_usart_receive_chars_dma(struct uart_port *port) { struct stm32_port *stm32_port = to_stm32_port(port); - unsigned int dma_size; + unsigned int dma_size, size = 0; /* DMA buffer is configured in cyclic mode and handles the rollback of the buffer. */ if (stm32_port->rx_dma_state.residue > stm32_port->last_res) { /* Conditional first part: from last_res to end of DMA buffer */ dma_size = stm32_port->last_res; stm32_usart_push_buffer_dma(port, dma_size); + size = dma_size; } dma_size = stm32_port->last_res - stm32_port->rx_dma_state.residue; stm32_usart_push_buffer_dma(port, dma_size); + size += dma_size; + + return size; } -static void stm32_usart_receive_chars(struct uart_port *port, bool irqflag) +static unsigned int stm32_usart_receive_chars(struct uart_port *port, bool force_dma_flush) { - struct tty_port *tport = &port->state->port; struct stm32_port *stm32_port = to_stm32_port(port); const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; enum dma_status rx_dma_status; - unsigned long flags; u32 sr; + unsigned int size = 0; - if (irqflag) - spin_lock_irqsave(&port->lock, flags); - else - spin_lock(&port->lock); - - if (stm32_usart_rx_dma_enabled(port)) { + if (stm32_usart_rx_dma_enabled(port) || force_dma_flush) { rx_dma_status = dmaengine_tx_status(stm32_port->rx_ch, stm32_port->rx_ch->cookie, &stm32_port->rx_dma_state); if (rx_dma_status == DMA_IN_PROGRESS) { /* Empty DMA buffer */ - stm32_usart_receive_chars_dma(port); + size = stm32_usart_receive_chars_dma(port); sr = readl_relaxed(port->membase + ofs->isr); if (sr & USART_SR_ERR_MASK) { /* Disable DMA request line */ stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR); /* Switch to PIO mode to handle the errors */ - stm32_usart_receive_chars_pio(port); + size += stm32_usart_receive_chars_pio(port); /* Switch back to DMA mode */ stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAR); @@ -354,18 +356,13 @@ static void stm32_usart_receive_chars(struct uart_port *port, bool irqflag) stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR); /* Fall back to interrupt mode */ dev_dbg(port->dev, "DMA error, fallback to irq mode\n"); - stm32_usart_receive_chars_pio(port); + size = stm32_usart_receive_chars_pio(port); } } else { - stm32_usart_receive_chars_pio(port); + size = stm32_usart_receive_chars_pio(port); } - if (irqflag) - uart_unlock_and_check_sysrq_irqrestore(port, irqflag); - else - uart_unlock_and_check_sysrq(port); - - tty_flip_buffer_push(tport); + return size; } static void stm32_usart_tx_dma_complete(void *arg) @@ -403,8 +400,15 @@ static void stm32_usart_tx_interrupt_enable(struct uart_port *port) static void stm32_usart_rx_dma_complete(void *arg) { struct uart_port *port = arg; + struct tty_port *tport = &port->state->port; + unsigned int size; + unsigned long flags; - stm32_usart_receive_chars(port, true); + spin_lock_irqsave(&port->lock, flags); + size = stm32_usart_receive_chars(port, false); + uart_unlock_and_check_sysrq_irqrestore(port, flags); + if (size) + tty_flip_buffer_push(tport); } static void stm32_usart_tx_interrupt_disable(struct uart_port *port) @@ -557,6 +561,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) struct stm32_port *stm32_port = to_stm32_port(port); const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; u32 sr; + unsigned int size; sr = readl_relaxed(port->membase + ofs->isr); @@ -580,7 +585,11 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) if (!stm32_port->throttled) { if (((sr & USART_SR_RXNE) && !stm32_usart_rx_dma_enabled(port)) || ((sr & USART_SR_ERR_MASK) && stm32_usart_rx_dma_enabled(port))) { - stm32_usart_receive_chars(port, false); + spin_lock(&port->lock); + size = stm32_usart_receive_chars(port, false); + uart_unlock_and_check_sysrq(port); + if (size) + tty_flip_buffer_push(tport); } } @@ -599,11 +608,19 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) static irqreturn_t stm32_usart_threaded_interrupt(int irq, void *ptr) { struct uart_port *port = ptr; + struct tty_port *tport = &port->state->port; struct stm32_port *stm32_port = to_stm32_port(port); + unsigned int size; + unsigned long flags; /* Receiver timeout irq for DMA RX */ - if (!stm32_port->throttled) - stm32_usart_receive_chars(port, false); + if (!stm32_port->throttled) { + spin_lock_irqsave(&port->lock, flags); + size = stm32_usart_receive_chars(port, false); + uart_unlock_and_check_sysrq_irqrestore(port, flags); + if (size) + tty_flip_buffer_push(tport); + } return IRQ_HANDLED; } @@ -1678,6 +1695,8 @@ static int __maybe_unused stm32_usart_serial_en_wakeup(struct uart_port *port, const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; struct tty_port *tport = &port->state->port; int ret; + unsigned int size; + unsigned long flags; if (!stm32_port->wakeup_src || !tty_port_initialized(tport)) return 0; @@ -1696,8 +1715,15 @@ static int __maybe_unused stm32_usart_serial_en_wakeup(struct uart_port *port, * low-power mode. */ if (stm32_port->rx_ch) { + spin_lock_irqsave(&port->lock, flags); + /* Avoid race with RX IRQ when DMAR is cleared */ stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR); - dmaengine_terminate_sync(stm32_port->rx_ch); + /* Poll data from DMA RX buffer if any */ + size = stm32_usart_receive_chars(port, true); + dmaengine_terminate_async(stm32_port->rx_ch); + uart_unlock_and_check_sysrq_irqrestore(port, flags); + if (size) + tty_flip_buffer_push(tport); } /* Poll data from RX FIFO if any */ |