Apple SoCs are a distant descendant of Samsung designs and use yet another variant of their UART style, with different interrupt handling.
In particular, this variant has the following differences with existing ones: * It includes a built-in interrupt controller with different registers, using only a single platform IRQ * Internal interrupt sources are treated as edge-triggered, even though the IRQ output is level-triggered. This chiefly affects the TX IRQ path: the driver can no longer rely on the TX buffer empty IRQ immediately firing after TX is enabled, but instead must prime the FIFO with data directly. Signed-off-by: Hector Martin <[email protected]> --- drivers/tty/serial/samsung_tty.c | 297 +++++++++++++++++++++++++++---- include/linux/serial_s3c.h | 16 ++ include/uapi/linux/serial_core.h | 3 + 3 files changed, 280 insertions(+), 36 deletions(-) diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c index 8ae3e03fbd8c..6d812ba1b748 100644 --- a/drivers/tty/serial/samsung_tty.c +++ b/drivers/tty/serial/samsung_tty.c @@ -56,6 +56,9 @@ /* flag to ignore all characters coming in */ #define RXSTAT_DUMMY_READ (0x10000000) +/* IRQ number used when the handler is called in non-IRQ context */ +#define NO_IRQ -1 + struct s3c24xx_uart_info { char *name; unsigned int type; @@ -144,6 +147,14 @@ struct s3c24xx_uart_port { #endif }; +enum s3c24xx_irq_type { + IRQ_DISCRETE = 0, + IRQ_S3C6400 = 1, + IRQ_APPLE = 2, +}; + +static void s3c24xx_serial_start_next_tx(struct s3c24xx_uart_port *ourport); + /* conversion functions */ #define s3c24xx_dev_to_port(__dev) dev_get_drvdata(__dev) @@ -231,11 +242,20 @@ static int s3c24xx_serial_txempty_nofifo(struct uart_port *port) /* * s3c64xx and later SoC's include the interrupt mask and status registers in * the controller itself, unlike the s3c24xx SoC's which have these registers - * in the interrupt controller. Check if the port type is s3c64xx or higher. + * in the interrupt controller. Apple SoCs use a different flavor of mask + * and status registers. This function returns the IRQ style to use. */ -static int s3c24xx_serial_has_interrupt_mask(struct uart_port *port) +static int s3c24xx_irq_type(struct uart_port *port) { - return to_ourport(port)->info->type == PORT_S3C6400; + switch (to_ourport(port)->info->type) { + case PORT_S3C6400: + return IRQ_S3C6400; + case PORT_APPLE: + return IRQ_APPLE; + default: + return IRQ_DISCRETE; + } + } static void s3c24xx_serial_rx_enable(struct uart_port *port) @@ -289,10 +309,17 @@ static void s3c24xx_serial_stop_tx(struct uart_port *port) if (!ourport->tx_enabled) return; - if (s3c24xx_serial_has_interrupt_mask(port)) + switch (s3c24xx_irq_type(port)) { + case IRQ_APPLE: + s3c24xx_clear_bit(port, APPLE_UCON_TXTHRESH_ENA, S3C2410_UCON); + break; + case IRQ_S3C6400: s3c24xx_set_bit(port, S3C64XX_UINTM_TXD, S3C64XX_UINTM); - else + break; + default: disable_irq_nosync(ourport->tx_irq); + break; + } if (dma && dma->tx_chan && ourport->tx_in_progress == S3C24XX_TX_DMA) { dmaengine_pause(dma->tx_chan); @@ -315,8 +342,6 @@ static void s3c24xx_serial_stop_tx(struct uart_port *port) ourport->tx_mode = 0; } -static void s3c24xx_serial_start_next_tx(struct s3c24xx_uart_port *ourport); - static void s3c24xx_serial_tx_dma_complete(void *args) { struct s3c24xx_uart_port *ourport = args; @@ -353,10 +378,17 @@ static void enable_tx_dma(struct s3c24xx_uart_port *ourport) u32 ucon; /* Mask Tx interrupt */ - if (s3c24xx_serial_has_interrupt_mask(port)) + switch (s3c24xx_irq_type(port)) { + case IRQ_APPLE: + WARN_ON(1); // No DMA + break; + case IRQ_S3C6400: s3c24xx_set_bit(port, S3C64XX_UINTM_TXD, S3C64XX_UINTM); - else + break; + default: disable_irq_nosync(ourport->tx_irq); + break; + } /* Enable tx dma mode */ ucon = rd_regl(port, S3C2410_UCON); @@ -369,6 +401,8 @@ static void enable_tx_dma(struct s3c24xx_uart_port *ourport) ourport->tx_mode = S3C24XX_TX_DMA; } +static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id); + static void enable_tx_pio(struct s3c24xx_uart_port *ourport) { struct uart_port *port = &ourport->port; @@ -383,16 +417,30 @@ static void enable_tx_pio(struct s3c24xx_uart_port *ourport) ucon = rd_regl(port, S3C2410_UCON); ucon &= ~(S3C64XX_UCON_TXMODE_MASK); ucon |= S3C64XX_UCON_TXMODE_CPU; - wr_regl(port, S3C2410_UCON, ucon); /* Unmask Tx interrupt */ - if (s3c24xx_serial_has_interrupt_mask(port)) - s3c24xx_clear_bit(port, S3C64XX_UINTM_TXD, - S3C64XX_UINTM); - else + switch (s3c24xx_irq_type(port)) { + case IRQ_APPLE: + ucon |= APPLE_UCON_TXTHRESH_ENA_MSK; + break; + case IRQ_S3C6400: + s3c24xx_clear_bit(port, S3C64XX_UINTM_TXD, S3C64XX_UINTM); + break; + default: enable_irq(ourport->tx_irq); + break; + } + + wr_regl(port, S3C2410_UCON, ucon); ourport->tx_mode = S3C24XX_TX_PIO; + + /* + * The Apple version only has edge triggered TX IRQs, so we need + * to kick off the process by sending some characters here. + */ + if (s3c24xx_irq_type(port) == IRQ_APPLE) + s3c24xx_serial_tx_chars(NO_IRQ, ourport); } static void s3c24xx_serial_start_tx_pio(struct s3c24xx_uart_port *ourport) @@ -513,11 +561,18 @@ static void s3c24xx_serial_stop_rx(struct uart_port *port) if (ourport->rx_enabled) { dev_dbg(port->dev, "stopping rx\n"); - if (s3c24xx_serial_has_interrupt_mask(port)) - s3c24xx_set_bit(port, S3C64XX_UINTM_RXD, - S3C64XX_UINTM); - else - disable_irq_nosync(ourport->rx_irq); + switch (s3c24xx_irq_type(port)) { + case IRQ_APPLE: + s3c24xx_clear_bit(port, APPLE_UCON_RXTHRESH_ENA, S3C2410_UCON); + s3c24xx_clear_bit(port, APPLE_UCON_RXTO_ENA, S3C2410_UCON); + break; + case IRQ_S3C6400: + s3c24xx_set_bit(port, S3C64XX_UINTM_RXD, S3C64XX_UINTM); + break; + default: + disable_irq_nosync(ourport->tx_irq); + break; + } ourport->rx_enabled = 0; } if (dma && dma->rx_chan) { @@ -651,14 +706,18 @@ static void enable_rx_pio(struct s3c24xx_uart_port *ourport) /* set Rx mode to DMA mode */ ucon = rd_regl(port, S3C2410_UCON); - ucon &= ~(S3C64XX_UCON_TIMEOUT_MASK | - S3C64XX_UCON_EMPTYINT_EN | - S3C64XX_UCON_DMASUS_EN | - S3C64XX_UCON_TIMEOUT_EN | - S3C64XX_UCON_RXMODE_MASK); - ucon |= 0xf << S3C64XX_UCON_TIMEOUT_SHIFT | - S3C64XX_UCON_TIMEOUT_EN | - S3C64XX_UCON_RXMODE_CPU; + ucon &= ~S3C64XX_UCON_RXMODE_MASK; + ucon |= S3C64XX_UCON_RXMODE_CPU; + + /* Apple types use these bits for IRQ masks */ + if (s3c24xx_irq_type(port) != IRQ_APPLE) { + ucon &= ~(S3C64XX_UCON_TIMEOUT_MASK | + S3C64XX_UCON_EMPTYINT_EN | + S3C64XX_UCON_DMASUS_EN | + S3C64XX_UCON_TIMEOUT_EN); + ucon |= 0xf << S3C64XX_UCON_TIMEOUT_SHIFT | + S3C64XX_UCON_TIMEOUT_EN; + } wr_regl(port, S3C2410_UCON, ucon); ourport->rx_mode = S3C24XX_RX_PIO; @@ -831,7 +890,9 @@ static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id) unsigned long flags; int count, dma_count = 0; - spin_lock_irqsave(&port->lock, flags); + /* Only lock if called from IRQ context */ + if (irq != NO_IRQ) + spin_lock_irqsave(&port->lock, flags); count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); @@ -893,7 +954,8 @@ static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id) s3c24xx_serial_stop_tx(port); out: - spin_unlock_irqrestore(&port->lock, flags); + if (irq != NO_IRQ) + spin_unlock_irqrestore(&port->lock, flags); return IRQ_HANDLED; } @@ -916,6 +978,26 @@ static irqreturn_t s3c64xx_serial_handle_irq(int irq, void *id) return ret; } +/* interrupt handler for Apple SoC's.*/ +static irqreturn_t apple_serial_handle_irq(int irq, void *id) +{ + struct s3c24xx_uart_port *ourport = id; + struct uart_port *port = &ourport->port; + unsigned int pend = rd_regl(port, S3C2410_UTRSTAT); + irqreturn_t ret = IRQ_HANDLED; + + if (pend & (APPLE_UTRSTAT_RXTHRESH | APPLE_UTRSTAT_RXTO)) { + wr_regl(port, S3C2410_UTRSTAT, APPLE_UTRSTAT_RXTHRESH | APPLE_UTRSTAT_RXTO); + ret = s3c24xx_serial_rx_chars(irq, id); + } + if (pend & APPLE_UTRSTAT_TXTHRESH) { + wr_regl(port, S3C2410_UTRSTAT, APPLE_UTRSTAT_TXTHRESH); + ret = s3c24xx_serial_tx_chars(irq, id); + } + + return ret; +} + static unsigned int s3c24xx_serial_tx_empty(struct uart_port *port) { struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port); @@ -1098,7 +1180,7 @@ static void s3c24xx_serial_shutdown(struct uart_port *port) struct s3c24xx_uart_port *ourport = to_ourport(port); if (ourport->tx_claimed) { - if (!s3c24xx_serial_has_interrupt_mask(port)) + if (s3c24xx_irq_type(port) == IRQ_DISCRETE) free_irq(ourport->tx_irq, ourport); ourport->tx_enabled = 0; ourport->tx_claimed = 0; @@ -1106,18 +1188,34 @@ static void s3c24xx_serial_shutdown(struct uart_port *port) } if (ourport->rx_claimed) { - if (!s3c24xx_serial_has_interrupt_mask(port)) + if (s3c24xx_irq_type(port) == IRQ_DISCRETE) free_irq(ourport->rx_irq, ourport); ourport->rx_claimed = 0; ourport->rx_enabled = 0; } /* Clear pending interrupts and mask all interrupts */ - if (s3c24xx_serial_has_interrupt_mask(port)) { + switch (s3c24xx_irq_type(port)) { + case IRQ_APPLE: { + unsigned int ucon; + + ucon = rd_regl(port, S3C2410_UCON); + ucon &= ~(APPLE_UCON_TXTHRESH_ENA_MSK | + APPLE_UCON_RXTHRESH_ENA_MSK | + APPLE_UCON_RXTO_ENA_MSK); + wr_regl(port, S3C2410_UCON, ucon); + + wr_regl(port, S3C2410_UTRSTAT, APPLE_UTRSTAT_ALL_FLAGS); + + free_irq(port->irq, ourport); + break; + } + case IRQ_S3C6400: free_irq(port->irq, ourport); wr_regl(port, S3C64XX_UINTP, 0xf); wr_regl(port, S3C64XX_UINTM, 0xf); + break; } if (ourport->dma) @@ -1215,6 +1313,47 @@ static int s3c64xx_serial_startup(struct uart_port *port) return ret; } +static int apple_serial_startup(struct uart_port *port) +{ + struct s3c24xx_uart_port *ourport = to_ourport(port); + unsigned long flags; + unsigned int ufcon; + int ret; + + wr_regl(port, S3C2410_UTRSTAT, APPLE_UTRSTAT_ALL_FLAGS); + + ret = request_irq(port->irq, apple_serial_handle_irq, IRQF_SHARED, + s3c24xx_serial_portname(port), ourport); + if (ret) { + dev_err(port->dev, "cannot get irq %d\n", port->irq); + return ret; + } + + /* For compatibility with s3c24xx Soc's */ + ourport->rx_enabled = 1; + ourport->rx_claimed = 1; + ourport->tx_enabled = 0; + ourport->tx_claimed = 1; + + spin_lock_irqsave(&port->lock, flags); + + ufcon = rd_regl(port, S3C2410_UFCON); + ufcon |= S3C2410_UFCON_RESETRX | S5PV210_UFCON_RXTRIG8; + if (!uart_console(port)) + ufcon |= S3C2410_UFCON_RESETTX; + wr_regl(port, S3C2410_UFCON, ufcon); + + enable_rx_pio(ourport); + + spin_unlock_irqrestore(&port->lock, flags); + + /* Enable Rx Interrupt */ + s3c24xx_set_bit(port, APPLE_UCON_RXTHRESH_ENA, S3C2410_UCON); + s3c24xx_set_bit(port, APPLE_UCON_RXTO_ENA, S3C2410_UCON); + + return ret; +} + /* power power management control */ static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level, @@ -1544,6 +1683,8 @@ static const char *s3c24xx_serial_type(struct uart_port *port) return "S3C2412"; case PORT_S3C6400: return "S3C6400/10"; + case PORT_APPLE: + return "APPLE"; default: return NULL; } @@ -1868,9 +2009,16 @@ static int s3c24xx_serial_init_port(struct s3c24xx_uart_port *ourport, /* setup info for port */ port->dev = &platdev->dev; + switch (s3c24xx_irq_type(port)) { + /* Startup sequence is different for Apple SoC's */ + case IRQ_APPLE: + s3c24xx_serial_ops.startup = apple_serial_startup; + break; /* Startup sequence is different for s3c64xx and higher SoC's */ - if (s3c24xx_serial_has_interrupt_mask(port)) + case IRQ_S3C6400: s3c24xx_serial_ops.startup = s3c64xx_serial_startup; + break; + } port->uartclk = 1; @@ -1905,7 +2053,7 @@ static int s3c24xx_serial_init_port(struct s3c24xx_uart_port *ourport, ourport->tx_irq = ret + 1; } - if (!s3c24xx_serial_has_interrupt_mask(port)) { + if (s3c24xx_irq_type(port) == IRQ_DISCRETE) { ret = platform_get_irq(platdev, 1); if (ret > 0) ourport->tx_irq = ret; @@ -1945,10 +2093,24 @@ static int s3c24xx_serial_init_port(struct s3c24xx_uart_port *ourport, pr_warn("uart: failed to enable baudclk\n"); /* Keep all interrupts masked and cleared */ - if (s3c24xx_serial_has_interrupt_mask(port)) { + switch (s3c24xx_irq_type(port)) { + case IRQ_APPLE: { + unsigned int ucon; + + ucon = rd_regl(port, S3C2410_UCON); + ucon &= ~(APPLE_UCON_TXTHRESH_ENA_MSK | + APPLE_UCON_RXTHRESH_ENA_MSK | + APPLE_UCON_RXTO_ENA_MSK); + wr_regl(port, S3C2410_UCON, ucon); + + wr_regl(port, S3C2410_UTRSTAT, APPLE_UTRSTAT_ALL_FLAGS); + break; + } + case IRQ_S3C6400: wr_regl(port, S3C64XX_UINTM, 0xf); wr_regl(port, S3C64XX_UINTP, 0xf); wr_regl(port, S3C64XX_UINTSP, 0xf); + break; } dev_dbg(port->dev, "port: map=%pa, mem=%p, irq=%d (%d,%d), clock=%u\n", @@ -2142,7 +2304,33 @@ static int s3c24xx_serial_resume_noirq(struct device *dev) if (port) { /* restore IRQ mask */ - if (s3c24xx_serial_has_interrupt_mask(port)) { + switch (s3c24xx_irq_type(port)) { + case IRQ_APPLE: + unsigned int ucon; + + clk_prepare_enable(ourport->clk); + if (!IS_ERR(ourport->baudclk)) + clk_prepare_enable(ourport->baudclk); + + ucon = rd_regl(port, S3C2410_UCON); + + ucon &= ~(APPLE_UCON_TXTHRESH_ENA_MSK | + APPLE_UCON_RXTHRESH_ENA_MSK | + APPLE_UCON_RXTO_ENA_MSK); + + if (ourport->tx_enabled) + ucon |= APPLE_UCON_TXTHRESH_ENA_MSK; + if (ourport->rx_enabled) + ucon |= APPLE_UCON_RXTHRESH_ENA_MSK | + APPLE_UCON_RXTO_ENA_MSK; + + wr_regl(port, S3C2410_UCON, ucon); + + if (!IS_ERR(ourport->baudclk)) + clk_disable_unprepare(ourport->baudclk); + clk_disable_unprepare(ourport->clk); + break; + case IRQ_S3C6400: unsigned int uintm = 0xf; if (ourport->tx_enabled) @@ -2156,6 +2344,7 @@ static int s3c24xx_serial_resume_noirq(struct device *dev) if (!IS_ERR(ourport->baudclk)) clk_disable_unprepare(ourport->baudclk); clk_disable_unprepare(ourport->clk); + break; } } @@ -2556,6 +2745,34 @@ static struct s3c24xx_serial_drv_data exynos5433_serial_drv_data = { #define EXYNOS5433_SERIAL_DRV_DATA (kernel_ulong_t)NULL #endif +#if defined(CONFIG_ARCH_APPLE) +static struct s3c24xx_serial_drv_data s5l_serial_drv_data = { + .info = &(struct s3c24xx_uart_info) { + .name = "Apple S5L UART", + .type = PORT_APPLE, + .fifosize = 16, + .rx_fifomask = S3C2410_UFSTAT_RXMASK, + .rx_fifoshift = S3C2410_UFSTAT_RXSHIFT, + .rx_fifofull = S3C2410_UFSTAT_RXFULL, + .tx_fifofull = S3C2410_UFSTAT_TXFULL, + .tx_fifomask = S3C2410_UFSTAT_TXMASK, + .tx_fifoshift = S3C2410_UFSTAT_TXSHIFT, + .def_clk_sel = S3C2410_UCON_CLKSEL0, + .num_clks = 1, + .clksel_mask = 0, + .clksel_shift = 0, + }, + .def_cfg = &(struct s3c2410_uartcfg) { + .ucon = APPLE_UCON_DEFAULT, + .ufcon = S3C2410_UFCON_DEFAULT, + }, +}; +#define S5L_SERIAL_DRV_DATA ((kernel_ulong_t)&s5l_serial_drv_data) +#else +#define S5L_SERIAL_DRV_DATA ((kernel_ulong_t)NULL) +#endif + + static const struct platform_device_id s3c24xx_serial_driver_ids[] = { { .name = "s3c2410-uart", @@ -2578,6 +2795,9 @@ static const struct platform_device_id s3c24xx_serial_driver_ids[] = { }, { .name = "exynos5433-uart", .driver_data = EXYNOS5433_SERIAL_DRV_DATA, + }, { + .name = "s5l-uart", + .driver_data = S5L_SERIAL_DRV_DATA, }, { }, }; @@ -2599,6 +2819,8 @@ static const struct of_device_id s3c24xx_uart_dt_match[] = { .data = (void *)EXYNOS4210_SERIAL_DRV_DATA }, { .compatible = "samsung,exynos5433-uart", .data = (void *)EXYNOS5433_SERIAL_DRV_DATA }, + { .compatible = "AAPL,s5l-uart", + .data = (void *)S5L_SERIAL_DRV_DATA }, {}, }; MODULE_DEVICE_TABLE(of, s3c24xx_uart_dt_match); @@ -2694,6 +2916,9 @@ static int __init s3c2410_early_console_setup(struct earlycon_device *device, OF_EARLYCON_DECLARE(s3c2410, "samsung,s3c2410-uart", s3c2410_early_console_setup); +/* Apple SoCs are close enough to s3c2410 for earlycon */ +OF_EARLYCON_DECLARE(s5l, "AAPL,s5l-uart", + s3c2410_early_console_setup); /* S3C2412, S3C2440, S3C64xx */ static struct samsung_early_console_data s3c2440_early_console_data = { diff --git a/include/linux/serial_s3c.h b/include/linux/serial_s3c.h index ca2c5393dc6b..377c8c6e5b97 100644 --- a/include/linux/serial_s3c.h +++ b/include/linux/serial_s3c.h @@ -246,6 +246,22 @@ S5PV210_UFCON_TXTRIG4 | \ S5PV210_UFCON_RXTRIG4) + +#define APPLE_UCON_RXTO_ENA 9 +#define APPLE_UCON_RXTHRESH_ENA 12 +#define APPLE_UCON_TXTHRESH_ENA 13 +#define APPLE_UCON_RXTO_ENA_MSK (1 << APPLE_UCON_RXTO_ENA) +#define APPLE_UCON_RXTHRESH_ENA_MSK (1 << APPLE_UCON_RXTHRESH_ENA) +#define APPLE_UCON_TXTHRESH_ENA_MSK (1 << APPLE_UCON_TXTHRESH_ENA) + +#define APPLE_UCON_DEFAULT S3C2410_UCON_RXFIFO_TOI + +#define APPLE_UTRSTAT_RXTHRESH (1<<4) +#define APPLE_UTRSTAT_TXTHRESH (1<<5) +#define APPLE_UTRSTAT_RXTO (1<<9) +#define APPLE_UTRSTAT_ALL_FLAGS (0x3f0) + + #ifndef __ASSEMBLY__ #include <linux/serial_core.h> diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h index 62c22045fe65..59d102b674db 100644 --- a/include/uapi/linux/serial_core.h +++ b/include/uapi/linux/serial_core.h @@ -277,4 +277,7 @@ /* Freescale LINFlexD UART */ #define PORT_LINFLEXUART 122 +/* Apple Silicon (M1/T8103) UART (Samsung variant) */ +#define PORT_APPLE 123 + #endif /* _UAPILINUX_SERIAL_CORE_H */ -- 2.30.0
