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author | Jiri Slaby (SUSE) <jirislaby@kernel.org> | 2024-04-05 09:08:23 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-04-09 16:28:03 +0300 |
commit | 1788cf6a91d9fa9aa61fc2917afe192c23d67f6a (patch) | |
tree | 38f5efd7c979768ead681553a234a9205e9acbed /drivers/tty/serial/sunhv.c | |
parent | f8fef2fa419febbfed2d04f0518111565df2673d (diff) | |
download | linux-1788cf6a91d9fa9aa61fc2917afe192c23d67f6a.tar.xz |
tty: serial: switch from circ_buf to kfifo
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) <jirislaby@kernel.org>
Cc: Al Cooper <alcooperx@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
Cc: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Neil Armstrong <neil.armstrong@linaro.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: Taichi Sugaya <sugaya.taichi@socionext.com>
Cc: Takao Orito <orito.takao@socionext.com>
Cc: Bjorn Andersson <andersson@kernel.org>
Cc: Konrad Dybcio <konrad.dybcio@linaro.org>
Cc: Pali Rohár <pali@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Alim Akhtar <alim.akhtar@samsung.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Orson Zhai <orsonzhai@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Hammer Hsieh <hammerh0314@gmail.com>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Timur Tabi <timur@kernel.org>
Cc: Michal Simek <michal.simek@amd.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20240405060826.2521-13-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/sunhv.c')
-rw-r--r-- | drivers/tty/serial/sunhv.c | 35 |
1 files changed, 20 insertions, 15 deletions
diff --git a/drivers/tty/serial/sunhv.c b/drivers/tty/serial/sunhv.c index 8d612ab80680..7f60679fdde1 100644 --- a/drivers/tty/serial/sunhv.c +++ b/drivers/tty/serial/sunhv.c @@ -39,10 +39,13 @@ static char *con_read_page; static int hung_up = 0; -static void transmit_chars_putchar(struct uart_port *port, struct circ_buf *xmit) +static void transmit_chars_putchar(struct uart_port *port, + struct tty_port *tport) { - while (!uart_circ_empty(xmit)) { - long status = sun4v_con_putchar(xmit->buf[xmit->tail]); + unsigned char ch; + + while (kfifo_peek(&tport->xmit_fifo, &ch)) { + long status = sun4v_con_putchar(ch); if (status != HV_EOK) break; @@ -51,14 +54,16 @@ static void transmit_chars_putchar(struct uart_port *port, struct circ_buf *xmit } } -static void transmit_chars_write(struct uart_port *port, struct circ_buf *xmit) +static void transmit_chars_write(struct uart_port *port, struct tty_port *tport) { - while (!uart_circ_empty(xmit)) { - unsigned long ra = __pa(xmit->buf + xmit->tail); - unsigned long len, status, sent; + while (!kfifo_is_empty(&tport->xmit_fifo)) { + unsigned long len, ra, status, sent; + unsigned char *tail; + + len = kfifo_out_linear_ptr(&tport->xmit_fifo, &tail, + UART_XMIT_SIZE); + ra = __pa(tail); - len = CIRC_CNT_TO_END(xmit->head, xmit->tail, - UART_XMIT_SIZE); status = sun4v_con_write(ra, len, &sent); if (status != HV_EOK) break; @@ -165,7 +170,7 @@ static int receive_chars_read(struct uart_port *port) } struct sunhv_ops { - void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit); + void (*transmit_chars)(struct uart_port *port, struct tty_port *tport); int (*receive_chars)(struct uart_port *port); }; @@ -196,18 +201,18 @@ static struct tty_port *receive_chars(struct uart_port *port) static void transmit_chars(struct uart_port *port) { - struct circ_buf *xmit; + struct tty_port *tport; if (!port->state) return; - xmit = &port->state->xmit; - if (uart_circ_empty(xmit) || uart_tx_stopped(port)) + tport = &port->state->port; + if (kfifo_is_empty(&tport->xmit_fifo) || uart_tx_stopped(port)) return; - sunhv_ops->transmit_chars(port, xmit); + sunhv_ops->transmit_chars(port, tport); - if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) uart_write_wakeup(port); } |