From 1788cf6a91d9fa9aa61fc2917afe192c23d67f6a Mon Sep 17 00:00:00 2001 From: "Jiri Slaby (SUSE)" Date: Fri, 5 Apr 2024 08:08:23 +0200 Subject: tty: serial: switch from circ_buf to kfifo MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Switch from struct circ_buf to proper kfifo. kfifo provides much better API, esp. when wrap-around of the buffer needs to be taken into account. Look at pl011_dma_tx_refill() or cpm_uart_tx_pump() changes for example. Kfifo API can also fill in scatter-gather DMA structures, so it easier for that use case too. Look at lpuart_dma_tx() for example. Note that not all drivers can be converted to that (like atmel_serial), they handle DMA specially. Note that usb-serial uses kfifo for TX for ages. omap needed a bit more care as it needs to put a char into FIFO to start the DMA transfer when OMAP_DMA_TX_KICK is set. In that case, we have to do kfifo_dma_out_prepare twice: once to find out the tx_size (to find out if it is worths to do DMA at all -- size >= 4), the second time for the actual transfer. All traces of circ_buf are removed from serial_core.h (and its struct uart_state). Signed-off-by: Jiri Slaby (SUSE) Cc: Al Cooper Cc: Matthias Brugger Cc: AngeloGioacchino Del Regno Cc: Kumaravel Thiagarajan Cc: Tharun Kumar P Cc: Russell King Cc: Vineet Gupta Cc: Richard Genoud Cc: Nicolas Ferre Cc: Alexandre Belloni Cc: Claudiu Beznea Cc: Alexander Shiyan Cc: Baruch Siach Cc: Maciej W. Rozycki Cc: Shawn Guo Cc: Sascha Hauer Cc: Fabio Estevam Cc: Neil Armstrong Cc: Kevin Hilman Cc: Jerome Brunet Cc: Martin Blumenstingl Cc: Taichi Sugaya Cc: Takao Orito Cc: Bjorn Andersson Cc: Konrad Dybcio Cc: Pali Rohár Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Christophe Leroy Cc: Aneesh Kumar K.V Cc: Naveen N. Rao Cc: Manivannan Sadhasivam Cc: Krzysztof Kozlowski Cc: Alim Akhtar Cc: Laxman Dewangan Cc: Thierry Reding Cc: Jonathan Hunter Cc: Orson Zhai Cc: Baolin Wang Cc: Chunyan Zhang Cc: Patrice Chotard Cc: Maxime Coquelin Cc: Alexandre Torgue Cc: David S. Miller Cc: Hammer Hsieh Cc: Peter Korsgaard Cc: Timur Tabi Cc: Michal Simek Cc: Sumit Semwal Cc: Christian König Link: https://lore.kernel.org/r/20240405060826.2521-13-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/samsung_tty.c | 54 +++++++++++++++++++++------------------- 1 file changed, 28 insertions(+), 26 deletions(-) (limited to 'drivers/tty/serial/samsung_tty.c') diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c index a2d07e05c502..dc35eb77d2ef 100644 --- a/drivers/tty/serial/samsung_tty.c +++ b/drivers/tty/serial/samsung_tty.c @@ -329,7 +329,7 @@ static void s3c24xx_serial_tx_dma_complete(void *args) { struct s3c24xx_uart_port *ourport = args; struct uart_port *port = &ourport->port; - struct circ_buf *xmit = &port->state->xmit; + struct tty_port *tport = &port->state->port; struct s3c24xx_uart_dma *dma = ourport->dma; struct dma_tx_state state; unsigned long flags; @@ -348,7 +348,7 @@ static void s3c24xx_serial_tx_dma_complete(void *args) uart_xmit_advance(port, count); ourport->tx_in_progress = 0; - if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) uart_write_wakeup(port); s3c24xx_serial_start_next_tx(ourport); @@ -431,17 +431,15 @@ static void s3c24xx_serial_start_tx_pio(struct s3c24xx_uart_port *ourport) } static int s3c24xx_serial_start_tx_dma(struct s3c24xx_uart_port *ourport, - unsigned int count) + unsigned int count, unsigned int tail) { - struct uart_port *port = &ourport->port; - struct circ_buf *xmit = &port->state->xmit; struct s3c24xx_uart_dma *dma = ourport->dma; if (ourport->tx_mode != S3C24XX_TX_DMA) enable_tx_dma(ourport); dma->tx_size = count & ~(dma_get_cache_alignment() - 1); - dma->tx_transfer_addr = dma->tx_addr + xmit->tail; + dma->tx_transfer_addr = dma->tx_addr + tail; dma_sync_single_for_device(dma->tx_chan->device->dev, dma->tx_transfer_addr, dma->tx_size, @@ -468,11 +466,11 @@ static int s3c24xx_serial_start_tx_dma(struct s3c24xx_uart_port *ourport, static void s3c24xx_serial_start_next_tx(struct s3c24xx_uart_port *ourport) { struct uart_port *port = &ourport->port; - struct circ_buf *xmit = &port->state->xmit; - unsigned long count; + struct tty_port *tport = &port->state->port; + unsigned int count, tail; /* Get data size up to the end of buffer */ - count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); + count = kfifo_out_linear(&tport->xmit_fifo, &tail, UART_XMIT_SIZE); if (!count) { s3c24xx_serial_stop_tx(port); @@ -481,16 +479,16 @@ static void s3c24xx_serial_start_next_tx(struct s3c24xx_uart_port *ourport) if (!ourport->dma || !ourport->dma->tx_chan || count < ourport->min_dma_size || - xmit->tail & (dma_get_cache_alignment() - 1)) + tail & (dma_get_cache_alignment() - 1)) s3c24xx_serial_start_tx_pio(ourport); else - s3c24xx_serial_start_tx_dma(ourport, count); + s3c24xx_serial_start_tx_dma(ourport, count, tail); } static void s3c24xx_serial_start_tx(struct uart_port *port) { struct s3c24xx_uart_port *ourport = to_ourport(port); - struct circ_buf *xmit = &port->state->xmit; + struct tty_port *tport = &port->state->port; if (!ourport->tx_enabled) { if (port->flags & UPF_CONS_FLOW) @@ -502,7 +500,8 @@ static void s3c24xx_serial_start_tx(struct uart_port *port) } if (ourport->dma && ourport->dma->tx_chan) { - if (!uart_circ_empty(xmit) && !ourport->tx_in_progress) + if (!kfifo_is_empty(&tport->xmit_fifo) && + !ourport->tx_in_progress) s3c24xx_serial_start_next_tx(ourport); } } @@ -868,18 +867,19 @@ static irqreturn_t s3c24xx_serial_rx_irq(int irq, void *dev_id) static void s3c24xx_serial_tx_chars(struct s3c24xx_uart_port *ourport) { struct uart_port *port = &ourport->port; - struct circ_buf *xmit = &port->state->xmit; - int count, dma_count = 0; + struct tty_port *tport = &port->state->port; + unsigned int count, dma_count = 0, tail; - count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); + count = kfifo_out_linear(&tport->xmit_fifo, &tail, UART_XMIT_SIZE); if (ourport->dma && ourport->dma->tx_chan && count >= ourport->min_dma_size) { int align = dma_get_cache_alignment() - - (xmit->tail & (dma_get_cache_alignment() - 1)); + (tail & (dma_get_cache_alignment() - 1)); if (count - align >= ourport->min_dma_size) { dma_count = count - align; count = align; + tail += align; } } @@ -894,7 +894,7 @@ static void s3c24xx_serial_tx_chars(struct s3c24xx_uart_port *ourport) * stopped, disable the uart and exit */ - if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { + if (kfifo_is_empty(&tport->xmit_fifo) || uart_tx_stopped(port)) { s3c24xx_serial_stop_tx(port); return; } @@ -906,24 +906,25 @@ static void s3c24xx_serial_tx_chars(struct s3c24xx_uart_port *ourport) dma_count = 0; } - while (!uart_circ_empty(xmit) && count > 0) { - if (rd_regl(port, S3C2410_UFSTAT) & ourport->info->tx_fifofull) + while (!(rd_regl(port, S3C2410_UFSTAT) & ourport->info->tx_fifofull)) { + unsigned char ch; + + if (!uart_fifo_get(port, &ch)) break; - wr_reg(port, S3C2410_UTXH, xmit->buf[xmit->tail]); - uart_xmit_advance(port, 1); + wr_reg(port, S3C2410_UTXH, ch); count--; } if (!count && dma_count) { - s3c24xx_serial_start_tx_dma(ourport, dma_count); + s3c24xx_serial_start_tx_dma(ourport, dma_count, tail); return; } - if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) uart_write_wakeup(port); - if (uart_circ_empty(xmit)) + if (kfifo_is_empty(&tport->xmit_fifo)) s3c24xx_serial_stop_tx(port); } @@ -1118,7 +1119,8 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) /* TX buffer */ dma->tx_addr = dma_map_single(dma->tx_chan->device->dev, - p->port.state->xmit.buf, UART_XMIT_SIZE, + p->port.state->port.xmit_buf, + UART_XMIT_SIZE, DMA_TO_DEVICE); if (dma_mapping_error(dma->tx_chan->device->dev, dma->tx_addr)) { reason = "DMA mapping error for TX buffer"; -- cgit v1.2.3