OMAP3: PM: UART save/restore support for OFF-mode

If OFF-mode is enabled, each enabled UART will save its
context whenever clocks are disabled and restore it when
clocks are re-enabled.

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 8c161dde24a097dc2842374792801aaaec6b28f6..b834b7ebde563f697d18ed2225e390982cb5adfa 100644 (file)
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -49,6 +49,18 @@ struct omap_uart_state {
 
        struct plat_serial8250_port *p;
        struct list_head node;
+
+#if defined(CONFIG_ARCH_OMAP3) && defined(CONFIG_PM)
+       int context_valid;
+
+       /* Registers to be saved/restored for OFF-mode */
+       u16 dll;
+       u16 dlh;
+       u16 ier;
+       u16 sysc;
+       u16 scr;
+       u16 wer;
+#endif
 };
 
 static struct omap_uart_state omap_uart[OMAP_MAX_NR_PORTS];
@@ -114,6 +126,69 @@ static inline void __init omap_uart_reset(struct omap_uart_state *uart)
 }
 
 #ifdef CONFIG_PM
+#ifdef CONFIG_ARCH_OMAP3
+
+static int enable_off_mode; /* to be removed by full off-mode patches */
+
+static void omap_uart_save_context(struct omap_uart_state *uart)
+{
+       u16 lcr = 0;
+       struct plat_serial8250_port *p = uart->p;
+
+       if (!enable_off_mode)
+               return;
+
+       lcr = serial_read_reg(p, UART_LCR);
+       serial_write_reg(p, UART_LCR, 0xBF);
+       uart->dll = serial_read_reg(p, UART_DLL);
+       uart->dlh = serial_read_reg(p, UART_DLM);
+       serial_write_reg(p, UART_LCR, lcr);
+       uart->ier = serial_read_reg(p, UART_IER);
+       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);
+
+       uart->context_valid = 1;
+}
+
+static void omap_uart_restore_context(struct omap_uart_state *uart)
+{
+       u16 efr = 0;
+       struct plat_serial8250_port *p = uart->p;
+
+       if (!enable_off_mode)
+               return;
+
+       if (!uart->context_valid)
+               return;
+
+       uart->context_valid = 0;
+
+       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);
+       serial_write_reg(p, UART_LCR, 0x0); /* Operational mode */
+       serial_write_reg(p, UART_IER, 0x0);
+       serial_write_reg(p, UART_LCR, 0xBF); /* Config B mode */
+       serial_write_reg(p, UART_DLL, uart->dll);
+       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, 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 */
+}
+#else
+static inline void omap_uart_save_context(struct omap_uart_state *uart) {}
+static inline void omap_uart_restore_context(struct omap_uart_state *uart) {}
+#endif /* CONFIG_ARCH_OMAP3 */
+
 static void omap_uart_smart_idle_enable(struct omap_uart_state *uart,
                                          int enable)
 {
@@ -137,6 +212,7 @@ static inline void omap_uart_enable_clocks(struct omap_uart_state *uart)
        clk_enable(uart->ick);
        clk_enable(uart->fck);
        uart->clocked = 1;
+       omap_uart_restore_context(uart);
 }
 
 static inline void omap_uart_disable_clocks(struct omap_uart_state *uart)
@@ -144,6 +220,7 @@ static inline void omap_uart_disable_clocks(struct omap_uart_state *uart)
        if (!uart->clocked)
                return;
 
+       omap_uart_save_context(uart);
        uart->clocked = 0;
        clk_disable(uart->ick);
        clk_disable(uart->fck);

diff --git a/include/linux/serial_reg.h b/include/linux/serial_reg.h
index 96c0d93fc2cacd753926559b100c4791a621909c..850db2e805107fcf306b57bd835f4d931b22b6a8 100644 (file)
--- a/include/linux/serial_reg.h
+++ b/include/linux/serial_reg.h
@@ -323,6 +323,7 @@
 #define UART_OMAP_MVER         0x14    /* Module version register */
 #define UART_OMAP_SYSC         0x15    /* System configuration register */
 #define UART_OMAP_SYSS         0x16    /* System status register */
+#define UART_OMAP_WER          0x17    /* Wake-up enable register */
 
 #endif /* _LINUX_SERIAL_REG_H */