kernel/drivers/tty/serial/samsung_tty.c, branch linux-6.9.y

serial: samsung: honor fifosize from dts at first

2024-03-02T21:04:05Z

Currently for platforms which passes UART fifosize from DT gets override by local driver structure "s3c24xx_serial_drv_data", which is not intended. Change the code to honor fifosize from device tree at first. Signed-off-by: Tamseel Shams Link: https://lore.kernel.org/r/20240220101227.80741-1-m.shams@samsung.com Signed-off-by: Greg Kroah-Hartman

tty: serial: samsung: Remove superfluous braces in macro

2024-02-06T14:33:08Z

Commit 59f37b7370ef ("tty: serial: samsung: Remove USI initialization") removes parameters from EXYNOS_COMMON_SERIAL_DRV_DATA() macro, but leaves unnecessary empty braces. Remove those to fix the style. No functional change. Signed-off-by: Sam Protsenko Reviewed-by: Krzysztof Kozlowski Link: https://lore.kernel.org/r/20240202010507.22638-1-semen.protsenko@linaro.org Signed-off-by: Greg Kroah-Hartman

tty: serial: samsung: shrink memory footprint of ``struct s3c24xx_uart_info``

2024-01-28T03:05:19Z

Use u32 for the members of ``struct s3c24xx_uart_info`` that are used for register interactions. The purpose of these members becomes clearer. The greater benefit of this change is that it also reduces the memory footprint of the struct, allowing 64-bit architectures to use a single cacheline for the entire struct. struct s3c24xx_uart_info { const char * name; /* 0 8 */ enum s3c24xx_port_type type; /* 8 4 */ unsigned int port_type; /* 12 4 */ unsigned int fifosize; /* 16 4 */ u32 rx_fifomask; /* 20 4 */ u32 rx_fifoshift; /* 24 4 */ u32 rx_fifofull; /* 28 4 */ u32 tx_fifomask; /* 32 4 */ u32 tx_fifoshift; /* 36 4 */ u32 tx_fifofull; /* 40 4 */ u32 clksel_mask; /* 44 4 */ u32 clksel_shift; /* 48 4 */ u32 ucon_mask; /* 52 4 */ u8 def_clk_sel; /* 56 1 */ u8 num_clks; /* 57 1 */ u8 iotype; /* 58 1 */ bool has_divslot; /* 59 1 */ /* size: 64, cachelines: 1, members: 17 */ /* padding: 4 */ }; Reviewed-by: Sam Protsenko Signed-off-by: Tudor Ambarus Link: https://lore.kernel.org/r/20240119104526.1221243-20-tudor.ambarus@linaro.org Signed-off-by: Greg Kroah-Hartman

tty: serial: samsung: change has_divslot type to bool

2024-01-28T03:05:19Z

Since the driver was introduced the port features flags never extended. As we don't expect more flags soon that would bypass the first cacheline of ``struct s3c24xx_uart_info``, change the type of ``has_divslot`` to bool. Bitfields operations incur performance penalty when set or read as compared to direct types. Signed-off-by: Tudor Ambarus Link: https://lore.kernel.org/r/20240119104526.1221243-19-tudor.ambarus@linaro.org Signed-off-by: Greg Kroah-Hartman

tty: serial: samsung: shrink the clock selection to 8 clocks

2024-01-28T03:05:19Z

provides a clock selection pool of maximum 4 clocks. Update the driver to consider a pool selection of maximum 8 clocks. u8 is large enough to allow more clocks than are supported by the driver now, and not too big to cause spanning of ``struct s3c24xx_uart_info`` through 2 cachelines when compiled for arm64. The goal is to reduce the memory footprint of ``struct s3c24xx_uart_info``. Reviewed-by: Sam Protsenko Signed-off-by: Tudor Ambarus Link: https://lore.kernel.org/r/20240119104526.1221243-18-tudor.ambarus@linaro.org Signed-off-by: Greg Kroah-Hartman

tty: serial: samsung: change return type for s3c24xx_serial_rx_fifocnt()

2024-01-28T03:05:19Z

Change the return type of the s3c24xx_serial_rx_fifocnt() method to ``unsigned int`` as the method only returns the fifo size and does not handle error codes. Reviewed-by: Sam Protsenko Signed-off-by: Tudor Ambarus Link: https://lore.kernel.org/r/20240119104526.1221243-17-tudor.ambarus@linaro.org Signed-off-by: Greg Kroah-Hartman

tty: serial: samsung: return bool for s3c24xx_serial_console_txrdy()

2024-01-28T03:05:19Z

s3c24xx_serial_console_txrdy() returned just 0 or 1 to indicate whether the TX is empty or not. Change its return type to bool. Reviewed-by: Sam Protsenko Signed-off-by: Tudor Ambarus Link: https://lore.kernel.org/r/20240119104526.1221243-16-tudor.ambarus@linaro.org Signed-off-by: Greg Kroah-Hartman

tty: serial: samsung: return bool for s3c24xx_serial_txempty_nofifo()

2024-01-28T03:05:19Z

s3c24xx_serial_txempty_nofifo() returned either 0 or BIT(2), which is counterintuitive. Make the method return bool, and return true when TX is empty and false otherwise. Reviewed-by: Sam Protsenko Signed-off-by: Tudor Ambarus Link: https://lore.kernel.org/r/20240119104526.1221243-15-tudor.ambarus@linaro.org Signed-off-by: Greg Kroah-Hartman

tty: serial: samsung: don't compare with zero an if (bitwise expression)

2024-01-28T03:05:19Z

The bitwise AND with the fifo mask is used to check if the fifo is empty or not, it doesn't care about the length, thus the comparison with zero is implicit. Rely on the implicit comparison instead. Reviewed-by: Sam Protsenko Signed-off-by: Tudor Ambarus Link: https://lore.kernel.org/r/20240119104526.1221243-14-tudor.ambarus@linaro.org Signed-off-by: Greg Kroah-Hartman

tty: serial: samsung: make max_count unsigned int

2024-01-28T03:05:19Z

``max_count`` negative values are not used. Since ``port->fifosize`` is an unsigned int, make ``max_count`` the same. Reviewed-by: Sam Protsenko Signed-off-by: Tudor Ambarus Link: https://lore.kernel.org/r/20240119104526.1221243-13-tudor.ambarus@linaro.org Signed-off-by: Greg Kroah-Hartman