diff options
Diffstat (limited to 'arch/x86/platform/ce4100')
| -rw-r--r-- | arch/x86/platform/ce4100/ce4100.c | 94 |
1 files changed, 92 insertions, 2 deletions
diff --git a/arch/x86/platform/ce4100/ce4100.c b/arch/x86/platform/ce4100/ce4100.c index 0ede12bde45..d2c0d51a717 100644 --- a/arch/x86/platform/ce4100/ce4100.c +++ b/arch/x86/platform/ce4100/ce4100.c @@ -12,20 +12,110 @@ #include <linux/kernel.h> #include <linux/irq.h> #include <linux/module.h> +#include <linux/serial_reg.h> +#include <linux/serial_8250.h> #include <asm/setup.h> +#include <asm/io.h> static int ce4100_i8042_detect(void) { return 0; } -static void __init sdv_arch_setup(void) +static void __init sdv_find_smp_config(void) { } -static void __init sdv_find_smp_config(void) +#ifdef CONFIG_SERIAL_8250 + + +static unsigned int mem_serial_in(struct uart_port *p, int offset) +{ + offset = offset << p->regshift; + return readl(p->membase + offset); +} + +/* + * The UART Tx interrupts are not set under some conditions and therefore serial + * transmission hangs. This is a silicon issue and has not been root caused. The + * workaround for this silicon issue checks UART_LSR_THRE bit and UART_LSR_TEMT + * bit of LSR register in interrupt handler to see whether at least one of these + * two bits is set, if so then process the transmit request. If this workaround + * is not applied, then the serial transmission may hang. This workaround is for + * errata number 9 in Errata - B step. +*/ + +static unsigned int ce4100_mem_serial_in(struct uart_port *p, int offset) +{ + unsigned int ret, ier, lsr; + + if (offset == UART_IIR) { + offset = offset << p->regshift; + ret = readl(p->membase + offset); + if (ret & UART_IIR_NO_INT) { + /* see if the TX interrupt should have really set */ + ier = mem_serial_in(p, UART_IER); + /* see if the UART's XMIT interrupt is enabled */ + if (ier & UART_IER_THRI) { + lsr = mem_serial_in(p, UART_LSR); + /* now check to see if the UART should be + generating an interrupt (but isn't) */ + if (lsr & (UART_LSR_THRE | UART_LSR_TEMT)) + ret &= ~UART_IIR_NO_INT; + } + } + } else + ret = mem_serial_in(p, offset); + return ret; +} + +static void ce4100_mem_serial_out(struct uart_port *p, int offset, int value) +{ + offset = offset << p->regshift; + writel(value, p->membase + offset); +} + +static void ce4100_serial_fixup(int port, struct uart_port *up, + unsigned short *capabilites) +{ +#ifdef CONFIG_EARLY_PRINTK + /* + * Over ride the legacy port configuration that comes from + * asm/serial.h. Using the ioport driver then switching to the + * PCI memmaped driver hangs the IOAPIC + */ + if (up->iotype != UPIO_MEM32) { + up->uartclk = 14745600; + up->mapbase = 0xdffe0200; + set_fixmap_nocache(FIX_EARLYCON_MEM_BASE, + up->mapbase & PAGE_MASK); + up->membase = + (void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE); + up->membase += up->mapbase & ~PAGE_MASK; + up->iotype = UPIO_MEM32; + up->regshift = 2; + } +#endif + up->iobase = 0; + up->serial_in = ce4100_mem_serial_in; + up->serial_out = ce4100_mem_serial_out; + + *capabilites |= (1 << 12); +} + +static __init void sdv_serial_fixup(void) +{ + serial8250_set_isa_configurator(ce4100_serial_fixup); +} + +#else +static inline void sdv_serial_fixup(void); +#endif + +static void __init sdv_arch_setup(void) { + sdv_serial_fixup(); } /* |