summaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-omap2/serial.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/mach-omap2/serial.c')
-rw-r--r--arch/arm/mach-omap2/serial.c80
1 files changed, 69 insertions, 11 deletions
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 3771254dfa8..566e991ede8 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;
}
/**
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-19 01:59:11 +0000