// SPDX-License-Identifier: GPL-2.0+ /* * Synopsys DesignWare 8250 driver. * * Copyright 2011 Picochip, Jamie Iles. * Copyright 2013 Intel Corporation * * The Synopsys DesignWare 8250 has an extra feature whereby it detects if the * LCR is written whilst busy. If it is, then a busy detect interrupt is * raised, the LCR needs to be rewritten and the uart status register read. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "8250_dwlib.h" /* Offsets for the DesignWare specific registers */ #define DW_UART_USR 0x1f /* UART Status Register */ #define DW_UART_DMASA 0xa8 /* DMA Software Ack */ #define OCTEON_UART_USR 0x27 /* UART Status Register */ #define RZN1_UART_TDMACR 0x10c /* DMA Control Register Transmit Mode */ #define RZN1_UART_RDMACR 0x110 /* DMA Control Register Receive Mode */ /* DesignWare specific register fields */ #define DW_UART_MCR_SIRE BIT(6) /* Renesas specific register fields */ #define RZN1_UART_xDMACR_DMA_EN BIT(0) #define RZN1_UART_xDMACR_1_WORD_BURST (0 << 1) #define RZN1_UART_xDMACR_4_WORD_BURST (1 << 1) #define RZN1_UART_xDMACR_8_WORD_BURST (2 << 1) #define RZN1_UART_xDMACR_BLK_SZ(x) ((x) << 3) /* Quirks */ #define DW_UART_QUIRK_OCTEON BIT(0) #define DW_UART_QUIRK_ARMADA_38X BIT(1) #define DW_UART_QUIRK_SKIP_SET_RATE BIT(2) #define DW_UART_QUIRK_IS_DMA_FC BIT(3) static inline struct dw8250_data *clk_to_dw8250_data(struct notifier_block *nb) { return container_of(nb, struct dw8250_data, clk_notifier); } static inline struct dw8250_data *work_to_dw8250_data(struct work_struct *work) { return container_of(work, struct dw8250_data, clk_work); } static inline int dw8250_modify_msr(struct uart_port *p, int offset, int value) { struct dw8250_data *d = to_dw8250_data(p->private_data); /* Override any modem control signals if needed */ if (offset == UART_MSR) { value |= d->msr_mask_on; value &= ~d->msr_mask_off; } return value; } static void dw8250_force_idle(struct uart_port *p) { struct uart_8250_port *up = up_to_u8250p(p); serial8250_clear_and_reinit_fifos(up); (void)p->serial_in(p, UART_RX); } static void dw8250_check_lcr(struct uart_port *p, int value) { void __iomem *offset = p->membase + (UART_LCR << p->regshift); int tries = 1000; /* Make sure LCR write wasn't ignored */ while (tries--) { unsigned int lcr = p->serial_in(p, UART_LCR); if ((value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR)) return; dw8250_force_idle(p); #ifdef CONFIG_64BIT if (p->type == PORT_OCTEON) __raw_writeq(value & 0xff, offset); else #endif if (p->iotype == UPIO_MEM32) writel(value, offset); else if (p->iotype == UPIO_MEM32BE) iowrite32be(value, offset); else writeb(value, offset); } /* * FIXME: this deadlocks if port->lock is already held * dev_err(p->dev, "Couldn't set LCR to %d\n", value); */ } /* Returns once the transmitter is empty or we run out of retries */ static void dw8250_tx_wait_empty(struct uart_port *p) { unsigned int tries = 20000; unsigned int delay_threshold = tries - 1000; unsigned int lsr; while (tries--) { lsr = readb (p->membase + (UART_LSR << p->regshift)); if (lsr & UART_LSR_TEMT) break; /* The device is first given a chance to empty without delay, * to avoid slowdowns at high bitrates. If after 1000 tries * the buffer has still not emptied, allow more time for low- * speed links. */ if (tries < delay_threshold) udelay (1); } } static void dw8250_serial_out38x(struct uart_port *p, int offset, int value) { struct dw8250_data *d = to_dw8250_data(p->private_data); /* Allow the TX to drain before we reconfigure */ if (offset == UART_LCR) dw8250_tx_wait_empty(p); writeb(value, p->membase + (offset << p->regshift)); if (offset == UART_LCR && !d->uart_16550_compatible) dw8250_check_lcr(p, value); } static void dw8250_serial_out(struct uart_port *p, int offset, int value) { struct dw8250_data *d = to_dw8250_data(p->private_data); writeb(value, p->membase + (offset << p->regshift)); if (offset == UART_LCR && !d->uart_16550_compatible) dw8250_check_lcr(p, value); } static unsigned int dw8250_serial_in(struct uart_port *p, int offset) { unsigned int value = readb(p->membase + (offset << p->regshift)); return dw8250_modify_msr(p, offset, value); } #ifdef CONFIG_64BIT static unsigned int dw8250_serial_inq(struct uart_port *p, int offset) { unsigned int value; value = (u8)__raw_readq(p->membase + (offset << p->regshift)); return dw8250_modify_msr(p, offset, value); } static void dw8250_serial_outq(struct uart_port *p, int offset, int value) { struct dw8250_data *d = to_dw8250_data(p->private_data); value &= 0xff; __raw_writeq(value, p->membase + (offset << p->regshift)); /* Read back to ensure register write ordering. */ __raw_readq(p->membase + (UART_LCR << p->regshift)); if (offset == UART_LCR && !d->uart_16550_compatible) dw8250_check_lcr(p, value); } #endif /* CONFIG_64BIT */ static void dw8250_serial_out32(struct uart_port *p, int offset, int value) { struct dw8250_data *d = to_dw8250_data(p->private_data); writel(value, p->membase + (offset << p->regshift)); if (offset == UART_LCR && !d->uart_16550_compatible) dw8250_check_lcr(p, value); } static unsigned int dw8250_serial_in32(struct uart_port *p, int offset) { unsigned int value = readl(p->membase + (offset << p->regshift)); return dw8250_modify_msr(p, offset, value); } static void dw8250_serial_out32be(struct uart_port *p, int offset, int value) { struct dw8250_data *d = to_dw8250_data(p->private_data); iowrite32be(value, p->membase + (offset << p->regshift)); if (offset == UART_LCR && !d->uart_16550_compatible) dw8250_check_lcr(p, value); } static unsigned int dw8250_serial_in32be(struct uart_port *p, int offset) { unsigned int value = ioread32be(p->membase + (offset << p->regshift)); return dw8250_modify_msr(p, offset, value); } static int dw8250_handle_irq(struct uart_port *p) { struct uart_8250_port *up = up_to_u8250p(p); struct dw8250_data *d = to_dw8250_data(p->private_data); unsigned int iir = p->serial_in(p, UART_IIR); bool rx_timeout = (iir & 0x3f) == UART_IIR_RX_TIMEOUT; unsigned int quirks = d->pdata->quirks; unsigned int status; unsigned long flags; /* * There are ways to get Designware-based UARTs into a state where * they are asserting UART_IIR_RX_TIMEOUT but there is no actual * data available. If we see such a case then we'll do a bogus * read. If we don't do this then the "RX TIMEOUT" interrupt will * fire forever. * * This problem has only been observed so far when not in DMA mode * so we limit the workaround only to non-DMA mode. */ if (!up->dma && rx_timeout) { spin_lock_irqsave(&p->lock, flags); status = p->serial_in(p, UART_LSR); if (!(status & (UART_LSR_DR | UART_LSR_BI))) (void) p->serial_in(p, UART_RX); spin_unlock_irqrestore(&p->lock, flags); } /* Manually stop the Rx DMA transfer when acting as flow controller */ if (quirks & DW_UART_QUIRK_IS_DMA_FC && up->dma && up->dma->rx_running && rx_timeout) { status = p->serial_in(p, UART_LSR); if (status & (UART_LSR_DR | UART_LSR_BI)) { dw8250_writel_ext(p, RZN1_UART_RDMACR, 0); dw8250_writel_ext(p, DW_UART_DMASA, 1); } } if (serial8250_handle_irq(p, iir)) return 1; if ((iir & UART_IIR_BUSY) == UART_IIR_BUSY) { /* Clear the USR */ (void)p->serial_in(p, d->pdata->usr_reg); return 1; } return 0; } static void dw8250_clk_work_cb(struct work_struct *work) { struct dw8250_data *d = work_to_dw8250_data(work); struct uart_8250_port *up; unsigned long rate; rate = clk_get_rate(d->clk); if (rate <= 0) return; up = serial8250_get_port(d->data.line); serial8250_update_uartclk(&up->port, rate); } static int dw8250_clk_notifier_cb(struct notifier_block *nb, unsigned long event, void *data) { struct dw8250_data *d = clk_to_dw8250_data(nb); /* * We have no choice but to defer the uartclk update due to two * deadlocks. First one is caused by a recursive mutex lock which * happens when clk_set_rate() is called from dw8250_set_termios(). * Second deadlock is more tricky and is caused by an inverted order of * the clk and tty-port mutexes lock. It happens if clock rate change * is requested asynchronously while set_termios() is executed between * tty-port mutex lock and clk_set_rate() function invocation and * vise-versa. Anyway if we didn't have the reference clock alteration * in the dw8250_set_termios() method we wouldn't have needed this * deferred event handling complication. */ if (event == POST_RATE_CHANGE) { queue_work(system_unbound_wq, &d->clk_work); return NOTIFY_OK; } return NOTIFY_DONE; } static void dw8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old) { if (!state) pm_runtime_get_sync(port->dev); serial8250_do_pm(port, state, old); if (state) pm_runtime_put_sync_suspend(port->dev); } static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios, struct ktermios *old) { unsigned long newrate = tty_termios_baud_rate(termios) * 16; struct dw8250_data *d = to_dw8250_data(p->private_data); long rate; int ret; clk_disable_unprepare(d->clk); rate = clk_round_rate(d->clk, newrate); if (rate > 0) { /* * Note that any clock-notifer worker will block in * serial8250_update_uartclk() until we are done. */ ret = clk_set_rate(d->clk, newrate); if (!ret) p->uartclk = rate; } clk_prepare_enable(d->clk); dw8250_do_set_termios(p, termios, old); } static void dw8250_set_ldisc(struct uart_port *p, struct ktermios *termios) { struct uart_8250_port *up = up_to_u8250p(p); unsigned int mcr = p->serial_in(p, UART_MCR); if (up->capabilities & UART_CAP_IRDA) { if (termios->c_line == N_IRDA) mcr |= DW_UART_MCR_SIRE; else mcr &= ~DW_UART_MCR_SIRE; p->serial_out(p, UART_MCR, mcr); } serial8250_do_set_ldisc(p, termios); } /* * dw8250_fallback_dma_filter will prevent the UART from getting just any free * channel on platforms that have DMA engines, but don't have any channels * assigned to the UART. * * REVISIT: This is a work around for limitation in the DMA Engine API. Once the * core problem is fixed, this function is no longer needed. */ static bool dw8250_fallback_dma_filter(struct dma_chan *chan, void *param) { return false; } static bool dw8250_idma_filter(struct dma_chan *chan, void *param) { return param == chan->device->dev; } static u32 dw8250_rzn1_get_dmacr_burst(int max_burst) { if (max_burst >= 8) return RZN1_UART_xDMACR_8_WORD_BURST; else if (max_burst >= 4) return RZN1_UART_xDMACR_4_WORD_BURST; else return RZN1_UART_xDMACR_1_WORD_BURST; } static void dw8250_prepare_tx_dma(struct uart_8250_port *p) { struct uart_port *up = &p->port; struct uart_8250_dma *dma = p->dma; u32 val; dw8250_writel_ext(up, RZN1_UART_TDMACR, 0); val = dw8250_rzn1_get_dmacr_burst(dma->txconf.dst_maxburst) | RZN1_UART_xDMACR_BLK_SZ(dma->tx_size) | RZN1_UART_xDMACR_DMA_EN; dw8250_writel_ext(up, RZN1_UART_TDMACR, val); } static void dw8250_prepare_rx_dma(struct uart_8250_port *p) { struct uart_port *up = &p->port; struct uart_8250_dma *dma = p->dma; u32 val; dw8250_writel_ext(up, RZN1_UART_RDMACR, 0); val = dw8250_rzn1_get_dmacr_burst(dma->rxconf.src_maxburst) | RZN1_UART_xDMACR_BLK_SZ(dma->rx_size) | RZN1_UART_xDMACR_DMA_EN; dw8250_writel_ext(up, RZN1_UART_RDMACR, val); } static void dw8250_quirks(struct uart_port *p, struct dw8250_data *data) { struct device_node *np = p->dev->of_node; if (np) { unsigned int quirks = data->pdata->quirks; int id; /* get index of serial line, if found in DT aliases */ id = of_alias_get_id(np, "serial"); if (id >= 0) p->line = id; #ifdef CONFIG_64BIT if (quirks & DW_UART_QUIRK_OCTEON) { p->serial_in = dw8250_serial_inq; p->serial_out = dw8250_serial_outq; p->flags = UPF_SKIP_TEST | UPF_SHARE_IRQ | UPF_FIXED_TYPE; p->type = PORT_OCTEON; data->skip_autocfg = true; } #endif if (of_device_is_big_endian(np)) { p->iotype = UPIO_MEM32BE; p->serial_in = dw8250_serial_in32be; p->serial_out = dw8250_serial_out32be; } if (quirks & DW_UART_QUIRK_ARMADA_38X) p->serial_out = dw8250_serial_out38x; if (quirks & DW_UART_QUIRK_SKIP_SET_RATE) p->set_termios = dw8250_do_set_termios; if (quirks & DW_UART_QUIRK_IS_DMA_FC) { data->data.dma.txconf.device_fc = 1; data->data.dma.rxconf.device_fc = 1; data->data.dma.prepare_tx_dma = dw8250_prepare_tx_dma; data->data.dma.prepare_rx_dma = dw8250_prepare_rx_dma; } } else if (acpi_dev_present("APMC0D08", NULL, -1)) { p->iotype = UPIO_MEM32; p->regshift = 2; p->serial_in = dw8250_serial_in32; data->uart_16550_compatible = true; } /* Platforms with iDMA 64-bit */ if (platform_get_resource_byname(to_platform_device(p->dev), IORESOURCE_MEM, "lpss_priv")) { data->data.dma.rx_param = p->dev->parent; data->data.dma.tx_param = p->dev->parent; data->data.dma.fn = dw8250_idma_filter; } } static void dw8250_clk_disable_unprepare(void *data) { clk_disable_unprepare(data); } static void dw8250_reset_control_assert(void *data) { reset_control_assert(data); } static int dw8250_probe(struct platform_device *pdev) { struct uart_8250_port uart = {}, *up = &uart; struct uart_port *p = &up->port; struct device *dev = &pdev->dev; struct dw8250_data *data; struct resource *regs; int irq; int err; u32 val; regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!regs) return dev_err_probe(dev, -EINVAL, "no registers defined\n"); irq = platform_get_irq(pdev, 0); if (irq < 0) return irq; spin_lock_init(&p->lock); p->mapbase = regs->start; p->irq = irq; p->handle_irq = dw8250_handle_irq; p->pm = dw8250_do_pm; p->type = PORT_8250; p->flags = UPF_SHARE_IRQ | UPF_FIXED_PORT; p->dev = dev; p->iotype = UPIO_MEM; p->serial_in = dw8250_serial_in; p->serial_out = dw8250_serial_out; p->set_ldisc = dw8250_set_ldisc; p->set_termios = dw8250_set_termios; p->membase = devm_ioremap(dev, regs->start, resource_size(regs)); if (!p->membase) return -ENOMEM; data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; data->data.dma.fn = dw8250_fallback_dma_filter; data->pdata = device_get_match_data(p->dev); p->private_data = &data->data; data->uart_16550_compatible = device_property_read_bool(dev, "snps,uart-16550-compatible"); err = device_property_read_u32(dev, "reg-shift", &val); if (!err) p->regshift = val; err = device_property_read_u32(dev, "reg-io-width", &val); if (!err && val == 4) { p->iotype = UPIO_MEM32; p->serial_in = dw8250_serial_in32; p->serial_out = dw8250_serial_out32; } if (device_property_read_bool(dev, "dcd-override")) { /* Always report DCD as active */ data->msr_mask_on |= UART_MSR_DCD; data->msr_mask_off |= UART_MSR_DDCD; } if (device_property_read_bool(dev, "dsr-override")) { /* Always report DSR as active */ data->msr_mask_on |= UART_MSR_DSR; data->msr_mask_off |= UART_MSR_DDSR; } if (device_property_read_bool(dev, "cts-override")) { /* Always report CTS as active */ data->msr_mask_on |= UART_MSR_CTS; data->msr_mask_off |= UART_MSR_DCTS; } if (device_property_read_bool(dev, "ri-override")) { /* Always report Ring indicator as inactive */ data->msr_mask_off |= UART_MSR_RI; data->msr_mask_off |= UART_MSR_TERI; } /* Always ask for fixed clock rate from a property. */ device_property_read_u32(dev, "clock-frequency", &p->uartclk); /* If there is separate baudclk, get the rate from it. */ data->clk = devm_clk_get_optional(dev, "baudclk"); if (data->clk == NULL) data->clk = devm_clk_get_optional(dev, NULL); if (IS_ERR(data->clk)) return PTR_ERR(data->clk); INIT_WORK(&data->clk_work, dw8250_clk_work_cb); data->clk_notifier.notifier_call = dw8250_clk_notifier_cb; err = clk_prepare_enable(data->clk); if (err) return dev_err_probe(dev, err, "could not enable optional baudclk\n"); err = devm_add_action_or_reset(dev, dw8250_clk_disable_unprepare, data->clk); if (err) return err; if (data->clk) p->uartclk = clk_get_rate(data->clk); /* If no clock rate is defined, fail. */ if (!p->uartclk) return dev_err_probe(dev, -EINVAL, "clock rate not defined\n"); data->pclk = devm_clk_get_optional(dev, "apb_pclk"); if (IS_ERR(data->pclk)) return PTR_ERR(data->pclk); err = clk_prepare_enable(data->pclk); if (err) return dev_err_probe(dev, err, "could not enable apb_pclk\n"); err = devm_add_action_or_reset(dev, dw8250_clk_disable_unprepare, data->pclk); if (err) return err; data->rst = devm_reset_control_get_optional_exclusive(dev, NULL); if (IS_ERR(data->rst)) return PTR_ERR(data->rst); reset_control_deassert(data->rst); err = devm_add_action_or_reset(dev, dw8250_reset_control_assert, data->rst); if (err) return err; dw8250_quirks(p, data); /* If the Busy Functionality is not implemented, don't handle it */ if (data->uart_16550_compatible) p->handle_irq = NULL; if (!data->skip_autocfg) dw8250_setup_port(p); /* If we have a valid fifosize, try hooking up DMA */ if (p->fifosize) { data->data.dma.rxconf.src_maxburst = p->fifosize / 4; data->data.dma.txconf.dst_maxburst = p->fifosize / 4; up->dma = &data->data.dma; } data->data.line = serial8250_register_8250_port(up); if (data->data.line < 0) return data->data.line; /* * Some platforms may provide a reference clock shared between several * devices. In this case any clock state change must be known to the * UART port at least post factum. */ if (data->clk) { err = clk_notifier_register(data->clk, &data->clk_notifier); if (err) return dev_err_probe(dev, err, "Failed to set the clock notifier\n"); queue_work(system_unbound_wq, &data->clk_work); } platform_set_drvdata(pdev, data); pm_runtime_set_active(dev); pm_runtime_enable(dev); return 0; } static int dw8250_remove(struct platform_device *pdev) { struct dw8250_data *data = platform_get_drvdata(pdev); struct device *dev = &pdev->dev; pm_runtime_get_sync(dev); if (data->clk) { clk_notifier_unregister(data->clk, &data->clk_notifier); flush_work(&data->clk_work); } serial8250_unregister_port(data->data.line); pm_runtime_disable(dev); pm_runtime_put_noidle(dev); return 0; } #ifdef CONFIG_PM_SLEEP static int dw8250_suspend(struct device *dev) { struct dw8250_data *data = dev_get_drvdata(dev); serial8250_suspend_port(data->data.line); return 0; } static int dw8250_resume(struct device *dev) { struct dw8250_data *data = dev_get_drvdata(dev); serial8250_resume_port(data->data.line); return 0; } #endif /* CONFIG_PM_SLEEP */ #ifdef CONFIG_PM static int dw8250_runtime_suspend(struct device *dev) { struct dw8250_data *data = dev_get_drvdata(dev); clk_disable_unprepare(data->clk); clk_disable_unprepare(data->pclk); return 0; } static int dw8250_runtime_resume(struct device *dev) { struct dw8250_data *data = dev_get_drvdata(dev); clk_prepare_enable(data->pclk); clk_prepare_enable(data->clk); return 0; } #endif static const struct dev_pm_ops dw8250_pm_ops = { SET_SYSTEM_SLEEP_PM_OPS(dw8250_suspend, dw8250_resume) SET_RUNTIME_PM_OPS(dw8250_runtime_suspend, dw8250_runtime_resume, NULL) }; static const struct dw8250_platform_data dw8250_dw_apb = { .usr_reg = DW_UART_USR, }; static const struct dw8250_platform_data dw8250_octeon_3860_data = { .usr_reg = OCTEON_UART_USR, .quirks = DW_UART_QUIRK_OCTEON, }; static const struct dw8250_platform_data dw8250_armada_38x_data = { .usr_reg = DW_UART_USR, .quirks = DW_UART_QUIRK_ARMADA_38X, }; static const struct dw8250_platform_data dw8250_renesas_rzn1_data = { .usr_reg = DW_UART_USR, .cpr_val = 0x00012f32, .quirks = DW_UART_QUIRK_IS_DMA_FC, }; static const struct dw8250_platform_data dw8250_starfive_jh7100_data = { .usr_reg = DW_UART_USR, .quirks = DW_UART_QUIRK_SKIP_SET_RATE, }; static const struct of_device_id dw8250_of_match[] = { { .compatible = "snps,dw-apb-uart", .data = &dw8250_dw_apb }, { .compatible = "cavium,octeon-3860-uart", .data = &dw8250_octeon_3860_data }, { .compatible = "marvell,armada-38x-uart", .data = &dw8250_armada_38x_data }, { .compatible = "renesas,rzn1-uart", .data = &dw8250_renesas_rzn1_data }, { .compatible = "starfive,jh7100-uart", .data = &dw8250_starfive_jh7100_data }, { /* Sentinel */ } }; MODULE_DEVICE_TABLE(of, dw8250_of_match); static const struct acpi_device_id dw8250_acpi_match[] = { { "80860F0A", (kernel_ulong_t)&dw8250_dw_apb }, { "8086228A", (kernel_ulong_t)&dw8250_dw_apb }, { "AMD0020", (kernel_ulong_t)&dw8250_dw_apb }, { "AMDI0020", (kernel_ulong_t)&dw8250_dw_apb }, { "AMDI0022", (kernel_ulong_t)&dw8250_dw_apb }, { "APMC0D08", (kernel_ulong_t)&dw8250_dw_apb}, { "BRCM2032", (kernel_ulong_t)&dw8250_dw_apb }, { "HISI0031", (kernel_ulong_t)&dw8250_dw_apb }, { "INT33C4", (kernel_ulong_t)&dw8250_dw_apb }, { "INT33C5", (kernel_ulong_t)&dw8250_dw_apb }, { "INT3434", (kernel_ulong_t)&dw8250_dw_apb }, { "INT3435", (kernel_ulong_t)&dw8250_dw_apb }, { }, }; MODULE_DEVICE_TABLE(acpi, dw8250_acpi_match); static struct platform_driver dw8250_platform_driver = { .driver = { .name = "dw-apb-uart", .pm = &dw8250_pm_ops, .of_match_table = dw8250_of_match, .acpi_match_table = dw8250_acpi_match, }, .probe = dw8250_probe, .remove = dw8250_remove, }; module_platform_driver(dw8250_platform_driver); MODULE_AUTHOR("Jamie Iles"); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Synopsys DesignWare 8250 serial port driver"); MODULE_ALIAS("platform:dw-apb-uart");