diff options
Diffstat (limited to 'arch/arm/mach-omap2/serial.c')
| -rw-r--r-- | arch/arm/mach-omap2/serial.c | 80 |
1 files changed, 69 insertions, 11 deletions
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c index 3771254dfa81..566e991ede81 100644 --- a/arch/arm/mach-omap2/serial.c +++ b/arch/arm/mach-omap2/serial.c @@ -37,6 +37,9 @@ #define UART_OMAP_NO_EMPTY_FIFO_READ_IP_REV 0x52 #define UART_OMAP_WER 0x17 /* Wake-up enable register */ +#define UART_ERRATA_FIFO_FULL_ABORT (0x1 << 0) +#define UART_ERRATA_i202_MDR1_ACCESS (0x1 << 1) + /* * NOTE: By default the serial timeout is disabled as it causes lost characters * over the serial ports. This means that the UART clocks will stay on until @@ -64,6 +67,7 @@ struct omap_uart_state { struct list_head node; struct platform_device pdev; + u32 errata; #if defined(CONFIG_ARCH_OMAP3) && defined(CONFIG_PM) int context_valid; @@ -74,6 +78,7 @@ struct omap_uart_state { u16 sysc; u16 scr; u16 wer; + u16 mcr; #endif }; @@ -180,6 +185,42 @@ static inline void __init omap_uart_reset(struct omap_uart_state *uart) #if defined(CONFIG_PM) && defined(CONFIG_ARCH_OMAP3) +/* + * Work Around for Errata i202 (3430 - 1.12, 3630 - 1.6) + * The access to uart register after MDR1 Access + * causes UART to corrupt data. + * + * Need a delay = + * 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS) + * give 10 times as much + */ +static void omap_uart_mdr1_errataset(struct omap_uart_state *uart, u8 mdr1_val, + u8 fcr_val) +{ + struct plat_serial8250_port *p = uart->p; + u8 timeout = 255; + + serial_write_reg(p, UART_OMAP_MDR1, mdr1_val); + udelay(2); + serial_write_reg(p, UART_FCR, fcr_val | UART_FCR_CLEAR_XMIT | + UART_FCR_CLEAR_RCVR); + /* + * Wait for FIFO to empty: when empty, RX_FIFO_E bit is 0 and + * TX_FIFO_E bit is 1. + */ + while (UART_LSR_THRE != (serial_read_reg(p, UART_LSR) & + (UART_LSR_THRE | UART_LSR_DR))) { + timeout--; + if (!timeout) { + /* Should *never* happen. we warn and carry on */ + dev_crit(&uart->pdev.dev, "Errata i202: timedout %x\n", + serial_read_reg(p, UART_LSR)); + break; + } + udelay(1); + } +} + static void omap_uart_save_context(struct omap_uart_state *uart) { u16 lcr = 0; @@ -197,6 +238,9 @@ static void omap_uart_save_context(struct omap_uart_state *uart) uart->sysc = serial_read_reg(p, UART_OMAP_SYSC); uart->scr = serial_read_reg(p, UART_OMAP_SCR); uart->wer = serial_read_reg(p, UART_OMAP_WER); + serial_write_reg(p, UART_LCR, 0x80); + uart->mcr = serial_read_reg(p, UART_MCR); + serial_write_reg(p, UART_LCR, lcr); uart->context_valid = 1; } @@ -214,7 +258,10 @@ static void omap_uart_restore_context(struct omap_uart_state *uart) uart->context_valid = 0; - serial_write_reg(p, UART_OMAP_MDR1, 0x7); + if (uart->errata & UART_ERRATA_i202_MDR1_ACCESS) + omap_uart_mdr1_errataset(uart, 0x07, 0xA0); + else + serial_write_reg(p, UART_OMAP_MDR1, 0x7); serial_write_reg(p, UART_LCR, 0xBF); /* Config B mode */ efr = serial_read_reg(p, UART_EFR); serial_write_reg(p, UART_EFR, UART_EFR_ECB); @@ -225,14 +272,18 @@ static void omap_uart_restore_context(struct omap_uart_state *uart) serial_write_reg(p, UART_DLM, uart->dlh); serial_write_reg(p, UART_LCR, 0x0); /* Operational mode */ serial_write_reg(p, UART_IER, uart->ier); - serial_write_reg(p, UART_FCR, 0xA1); + serial_write_reg(p, UART_LCR, 0x80); + serial_write_reg(p, UART_MCR, uart->mcr); serial_write_reg(p, UART_LCR, 0xBF); /* Config B mode */ serial_write_reg(p, UART_EFR, efr); serial_write_reg(p, UART_LCR, UART_LCR_WLEN8); serial_write_reg(p, UART_OMAP_SCR, uart->scr); serial_write_reg(p, UART_OMAP_WER, uart->wer); serial_write_reg(p, UART_OMAP_SYSC, uart->sysc); - serial_write_reg(p, UART_OMAP_MDR1, 0x00); /* UART 16x mode */ + if (uart->errata & UART_ERRATA_i202_MDR1_ACCESS) + omap_uart_mdr1_errataset(uart, 0x00, 0xA1); + else + serial_write_reg(p, UART_OMAP_MDR1, 0x00); /* UART 16x mode */ } #else static inline void omap_uart_save_context(struct omap_uart_state *uart) {} @@ -489,8 +540,8 @@ static void omap_uart_idle_init(struct omap_uart_state *uart) } uart->wk_mask = wk_mask; } else { - uart->wk_en = 0; - uart->wk_st = 0; + uart->wk_en = NULL; + uart->wk_st = NULL; uart->wk_mask = 0; uart->padconf = 0; } @@ -552,7 +603,8 @@ static ssize_t sleep_timeout_store(struct device *dev, return n; } -DEVICE_ATTR(sleep_timeout, 0644, sleep_timeout_show, sleep_timeout_store); +static DEVICE_ATTR(sleep_timeout, 0644, sleep_timeout_show, + sleep_timeout_store); #define DEV_CREATE_FILE(dev, attr) WARN_ON(device_create_file(dev, attr)) #else static inline void omap_uart_idle_init(struct omap_uart_state *uart) {} @@ -749,14 +801,20 @@ void __init omap_serial_init_port(int port) * omap3xxx: Never read empty UART fifo on UARTs * with IP rev >=0x52 */ - if (cpu_is_omap44xx()) { - uart->p->serial_in = serial_in_override; - uart->p->serial_out = serial_out_override; - } else if ((serial_read_reg(uart->p, UART_OMAP_MVER) & 0xFF) - >= UART_OMAP_NO_EMPTY_FIFO_READ_IP_REV) { + if (cpu_is_omap44xx()) + uart->errata |= UART_ERRATA_FIFO_FULL_ABORT; + else if ((serial_read_reg(uart->p, UART_OMAP_MVER) & 0xFF) + >= UART_OMAP_NO_EMPTY_FIFO_READ_IP_REV) + uart->errata |= UART_ERRATA_FIFO_FULL_ABORT; + + if (uart->errata & UART_ERRATA_FIFO_FULL_ABORT) { uart->p->serial_in = serial_in_override; uart->p->serial_out = serial_out_override; } + + /* Enable the MDR1 errata for OMAP3 */ + if (cpu_is_omap34xx()) + uart->errata |= UART_ERRATA_i202_MDR1_ACCESS; } /** |