diff options
| -rw-r--r-- | drivers/tty/serial/amba-pl011.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index c4df9cbc264b..fccec1698a54 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -152,6 +152,23 @@ static const struct vendor_data vendor_sbsa = { .fixed_options = true, }; +#ifdef CONFIG_ACPI_SPCR_TABLE +static const struct vendor_data vendor_qdt_qdf2400_e44 = { + .reg_offset = pl011_std_offsets, + .fr_busy = UART011_FR_TXFE, + .fr_dsr = UART01x_FR_DSR, + .fr_cts = UART01x_FR_CTS, + .fr_ri = UART011_FR_RI, + .inv_fr = UART011_FR_TXFE, + .access_32b = true, + .oversampling = false, + .dma_threshold = false, + .cts_event_workaround = false, + .always_enabled = true, + .fixed_options = true, +}; +#endif + static u16 pl011_st_offsets[REG_ARRAY_SIZE] = { [REG_DR] = UART01x_DR, [REG_ST_DMAWM] = ST_UART011_DMAWM, @@ -2451,6 +2468,15 @@ static int pl011_console_match(struct console *co, char *name, int idx, resource_size_t addr; int i; + /* + * Systems affected by the Qualcomm Technologies QDF2400 E44 erratum + * have a distinct console name, so make sure we check for that. + * The actual implementation of the erratum occurs in the probe + * function. + */ + if ((strcmp(name, "qdf2400_e44") != 0) && (strcmp(name, "pl011") != 0)) + return -ENODEV; + if (uart_parse_earlycon(options, &iotype, &addr, &options)) return -ENODEV; @@ -2491,6 +2517,22 @@ static struct console amba_console = { #define AMBA_CONSOLE (&amba_console) +static void qdf2400_e44_putc(struct uart_port *port, unsigned char c) +{ + while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF) + cpu_relax(); + writel(c, port->membase + UART01x_DR); + while (!(readl(port->membase + UART01x_FR) & UART011_FR_TXFE)) + cpu_relax(); +} + +static void qdf2400_e44_early_write(struct console *con, const char *s, unsigned int n) +{ + struct earlycon_device *dev = con->data; + + uart_console_write(&dev->port, s, n, qdf2400_e44_putc); +} + static void pl011_putc(struct uart_port *port, unsigned char c) { while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF) @@ -2569,6 +2611,29 @@ OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup); OF_EARLYCON_DECLARE(pl011, "arm,sbsa-uart", pl011_early_console_setup); +/* + * On Qualcomm Datacenter Technologies QDF2400 SOCs affected by + * Erratum 44, traditional earlycon can be enabled by specifying + * "earlycon=qdf2400_e44,<address>". Any options are ignored. + * + * Alternatively, you can just specify "earlycon", and the early console + * will be enabled with the information from the SPCR table. In this + * case, the SPCR code will detect the need for the E44 work-around, + * and set the console name to "qdf2400_e44". + */ +static int __init +qdf2400_e44_early_console_setup(struct earlycon_device *device, + const char *opt) +{ + if (!device->port.membase) + return -ENODEV; + + device->con->write = qdf2400_e44_early_write; + return 0; +} + +EARLYCON_DECLARE(qdf2400_e44, qdf2400_e44_early_console_setup); + #else #define AMBA_CONSOLE NULL #endif @@ -2804,6 +2869,22 @@ static int pl011_resume(struct device *dev) static SIMPLE_DEV_PM_OPS(pl011_dev_pm_ops, pl011_suspend, pl011_resume); +#ifdef CONFIG_ACPI_SPCR_TABLE +static void qpdf2400_erratum44_workaround(struct device *dev, + struct uart_amba_port *uap) +{ + if (!qdf2400_e44_present) + return; + + dev_info(dev, "working around QDF2400 SoC erratum 44\n"); + uap->vendor = &vendor_qdt_qdf2400_e44; +} +#else +static void qpdf2400_erratum44_workaround(struct device *dev, + struct uart_amba_port *uap) +{ /* empty */ } +#endif + static int sbsa_uart_probe(struct platform_device *pdev) { struct uart_amba_port *uap; @@ -2840,6 +2921,7 @@ static int sbsa_uart_probe(struct platform_device *pdev) uap->port.irq = ret; uap->vendor = &vendor_sbsa; + qpdf2400_erratum44_workaround(&pdev->dev, uap); uap->reg_offset = uap->vendor->reg_offset; uap->fifosize = 32; |