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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCHv2 3/5] xen/arm: Add the new OMAP UART driver.
TI OMAP UART introduces some features such as register access modes, which
makes its configuration and interrupt handling differs from 8250 compatible
UART. Thus, we seperate this driver from ns16550's implementation.
Signed-off-by: Chen Baozi <baozich@xxxxxxxxx>
---
config/arm32.mk | 1 +
xen/common/device_tree.c | 15 ++
xen/drivers/char/Makefile | 1 +
xen/drivers/char/omap-uart.c | 352 ++++++++++++++++++++++++++++++++++++++++++
xen/include/xen/8250-uart.h | 59 ++++++-
xen/include/xen/device_tree.h | 6 +
6 files changed, 431 insertions(+), 3 deletions(-)
create mode 100644 xen/drivers/char/omap-uart.c
diff --git a/config/arm32.mk b/config/arm32.mk
index 8e21158..76e229d 100644
--- a/config/arm32.mk
+++ b/config/arm32.mk
@@ -11,6 +11,7 @@ CFLAGS += -marm
HAS_PL011 := y
HAS_EXYNOS4210 := y
+HAS_OMAP := y
# Use only if calling $(LD) directly.
LDFLAGS_DIRECT += -EL
diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 84d704d..b392c60 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -574,6 +574,21 @@ const void *dt_get_property(const struct dt_device_node
*np,
return pp ? pp->value : NULL;
}
+int dt_property_read_u32(const struct dt_device_node *np,
+ const char *name, u32 *out_value)
+{
+ u32 len;
+ const __be32 *val;
+
+ val = dt_get_property(np, name, &len);
+ if ( !val || len > 4 )
+ return 1;
+
+ *out_value = be32_to_cpup(val);
+
+ return 0;
+}
+
bool_t dt_device_is_compatible(const struct dt_device_node *device,
const char *compat)
{
diff --git a/xen/drivers/char/Makefile b/xen/drivers/char/Makefile
index 37543f0..911b788 100644
--- a/xen/drivers/char/Makefile
+++ b/xen/drivers/char/Makefile
@@ -2,6 +2,7 @@ obj-y += console.o
obj-$(HAS_NS16550) += ns16550.o
obj-$(HAS_PL011) += pl011.o
obj-$(HAS_EXYNOS4210) += exynos4210-uart.o
+obj-$(HAS_OMAP) += omap-uart.o
obj-$(HAS_EHCI) += ehci-dbgp.o
obj-$(CONFIG_ARM) += dt-uart.o
obj-y += serial.o
diff --git a/xen/drivers/char/omap-uart.c b/xen/drivers/char/omap-uart.c
new file mode 100644
index 0000000..d5c2c34
--- /dev/null
+++ b/xen/drivers/char/omap-uart.c
@@ -0,0 +1,352 @@
+/*
+ * omap-uart.c
+ * Based on drivers/char/ns16550.c
+ *
+ * Driver for OMAP-UART contorller
+ *
+ * Copyright (C) 2012, Chen Baozi <baozich@xxxxxxxxx>
+ *
+ * Note: This driver is made separate from 16550-series UART driver as
+ * omap platform has some specific configurations
+ */
+
+#include <xen/config.h>
+#include <xen/console.h>
+#include <xen/serial.h>
+#include <xen/init.h>
+#include <xen/irq.h>
+#include <asm/early_printk.h>
+#include <xen/device_tree.h>
+#include <asm/device.h>
+#include <xen/errno.h>
+#include <xen/mm.h>
+#include <xen/vmap.h>
+#include <xen/8250-uart.h>
+
+#define omap_read(uart, off) ioreadl((uart)->regs + (off<<REG_SHIFT))
+#define omap_write(uart, off, val) iowritel((uart)->regs + (off<<REG_SHIFT),
(val))
+
+static struct omap_uart {
+ u32 baud, clock_hz, data_bits, parity, stop_bits, fifo_size;
+ struct dt_irq irq;
+ void __iomem *regs;
+ struct irqaction irqaction;
+} omap_com = {0};
+
+static void omap_uart_interrupt(int irq, void *data, struct cpu_user_regs
*regs)
+{
+ struct serial_port *port = data;
+ struct omap_uart *uart = port->uart;
+ u32 lsr;
+
+ while (!(omap_read(uart, UART_IIR) & UART_IIR_NOINT))
+ {
+ lsr = omap_read(uart, UART_LSR) & 0xff;
+ if (lsr & UART_LSR_THRE)
+ serial_tx_interrupt(port, regs);
+ if (lsr & UART_LSR_DR)
+ serial_rx_interrupt(port, regs);
+
+ if ( port->txbufc == port->txbufp )
+ omap_write(uart, UART_IER, UART_IER_ERDAI|UART_IER_ELSI);
+ };
+}
+
+static void baud_protocol_setup(struct omap_uart *uart)
+{
+ u32 dll, dlh, efr;
+ unsigned int divisor;
+
+ divisor = uart->clock_hz / (uart->baud << 4);
+ dll = divisor & 0xff;
+ dlh = divisor >> 8;
+
+ /*
+ * Switch to register configuration mode B to access the UART_OMAP_EFR
+ * register.
+ */
+ omap_write(uart, UART_LCR, UART_LCR_CONF_MODE_B);
+ /*
+ * Enable access to the UART_IER[7:4] bit field.
+ */
+ efr = omap_read(uart, UART_OMAP_EFR);
+ omap_write(uart, UART_OMAP_EFR, efr|UART_OMAP_EFR_ECB);
+ /*
+ * Switch to register operation mode to access the UART_IER register.
+ */
+ omap_write(uart, UART_LCR, 0);
+ /*
+ * Clear the UART_IER register (set the UART_IER[4] SLEEP_MODE bit
+ * to 0 to change the UART_DLL and UART_DLM register). Set the
+ * UART_IER register value to 0x0000.
+ */
+ omap_write(uart, UART_IER, 0);
+ /*
+ * Switch to register configuartion mode B to access the UART_DLL and
+ * UART_DLM registers.
+ */
+ omap_write(uart, UART_LCR, UART_LCR_CONF_MODE_B);
+ /*
+ * Load divisor value.
+ */
+ omap_write(uart, UART_DLL, dll);
+ omap_write(uart, UART_DLM, dlh);
+ /*
+ * Restore the UART_OMAP_EFR
+ */
+ omap_write(uart, UART_OMAP_EFR, efr);
+ /*
+ * Load the new protocol formatting (parity, stop-bit, character length)
+ * and switch to register operational mode.
+ */
+ omap_write(uart, UART_LCR, (uart->data_bits - 5) |
+ ((uart->stop_bits - 1) << 2) | uart->parity);
+}
+
+static void fifo_setup(struct omap_uart *uart)
+{
+ u32 lcr, efr, mcr;
+ /*
+ * Switch to register configuration mode B to access the UART_OMAP_EFR
+ * register.
+ */
+ lcr = omap_read(uart, UART_LCR);
+ omap_write(uart, UART_LCR, UART_LCR_CONF_MODE_B);
+ /*
+ * Enable register submode TCR_TLR to access the UART_OMAP_TLR register.
+ */
+ efr = omap_read(uart, UART_OMAP_EFR);
+ omap_write(uart, UART_OMAP_EFR, efr|UART_OMAP_EFR_ECB);
+ /*
+ * Switch to register configuration mode A to access the UART_MCR
+ * register.
+ */
+ omap_write(uart, UART_LCR, UART_LCR_CONF_MODE_A);
+ /*
+ * Enable register submode TCR_TLR to access the UART_OMAP_TLR register
+ */
+ mcr = omap_read(uart, UART_MCR);
+ omap_write(uart, UART_MCR, mcr|UART_MCR_TCRTLR);
+ /*
+ * Enable the FIFO; load the new FIFO trigger and the new DMA mode.
+ */
+ omap_write(uart, UART_FCR, UART_FCR_R_TRIG_01|
+ UART_FCR_T_TRIG_10|UART_FCR_ENABLE);
+ /*
+ * Switch to register configuration mode B to access the UART_EFR
+ * register.
+ */
+ omap_write(uart, UART_LCR, UART_LCR_CONF_MODE_B);
+ /*
+ * Load the new FIFO triggers and the new DMA mode bit.
+ */
+ omap_write(uart, UART_OMAP_SCR, OMAP_UART_SCR_RX_TRIG_GRANU1_MASK);
+ /*
+ * Restore the UART_OMAP_EFR[4] value.
+ */
+ omap_write(uart, UART_OMAP_EFR, efr);
+ /*
+ * Switch to register configuration mode A to access the UART_MCR
+ * register.
+ */
+ omap_write(uart, UART_LCR, UART_LCR_CONF_MODE_A);
+ /*
+ * Restore UART_MCR[6] value.
+ */
+ omap_write(uart, UART_MCR, mcr);
+ /*
+ * Restore UART_LCR value.
+ */
+ omap_write(uart, UART_LCR, lcr);
+}
+
+static void __init omap_uart_init_preirq(struct serial_port *port)
+{
+ struct omap_uart *uart = port->uart;
+
+ /*
+ * Clear the FIFO buffers.
+ */
+ omap_write(uart, UART_FCR, UART_FCR_ENABLE);
+ omap_write(uart, UART_FCR, UART_FCR_ENABLE|UART_FCR_CLRX|UART_FCR_CLTX);
+ omap_write(uart, UART_FCR, 0);
+
+ /*
+ * The TRM says the mode should be disabled while UART_DLL and UART_DHL
+ * are being changed so we disable before setup, then enable.
+ */
+ omap_write(uart, UART_OMAP_MDR1, UART_OMAP_MDR1_DISABLE);
+
+ /* Baud rate & protocol format setup */
+ baud_protocol_setup(uart);
+
+ /* FIFO setup */
+ fifo_setup(uart);
+
+ /* No flow control */
+ omap_write(uart, UART_MCR, UART_MCR_DTR|UART_MCR_RTS);
+
+ omap_write(uart, UART_OMAP_MDR1, UART_OMAP_MDR1_16X_MODE);
+
+ uart->fifo_size = 64;
+}
+
+static void __init omap_uart_init_postirq(struct serial_port *port)
+{
+ struct omap_uart *uart = port->uart;
+
+ uart->irqaction.handler = omap_uart_interrupt;
+ uart->irqaction.name = "omap_uart";
+ uart->irqaction.dev_id = port;
+
+ if ( setup_dt_irq(&uart->irq, &uart->irqaction) != 0 )
+ {
+ dprintk(XENLOG_ERR, "Failed to allocated omap_uart IRQ %d\n",
+ uart->irq.irq);
+ return;
+ }
+
+ /* Enable interrupts */
+ omap_write(uart, UART_IER, UART_IER_ERDAI|UART_IER_ETHREI|UART_IER_ELSI);
+}
+
+static void omap_uart_suspend(struct serial_port *port)
+{
+ BUG();
+}
+
+static void omap_uart_resume(struct serial_port *port)
+{
+ BUG();
+}
+
+static unsigned int omap_uart_tx_ready(struct serial_port *port)
+{
+ struct omap_uart *uart = port->uart;
+
+ omap_write(uart, UART_IER, UART_IER_ERDAI|UART_IER_ETHREI|UART_IER_ELSI);
+
+ return omap_read(uart, UART_LSR) & UART_LSR_THRE ? uart->fifo_size : 0;
+}
+
+static void omap_uart_putc(struct serial_port *port, char c)
+{
+ struct omap_uart *uart = port->uart;
+
+ omap_write(uart, UART_THR, (uint32_t)(unsigned char)c);
+}
+
+static int omap_uart_getc(struct serial_port *port, char *pc)
+{
+ struct omap_uart *uart = port->uart;
+
+ if ( !(omap_read(uart, UART_LSR) & UART_LSR_DR) )
+ return 0;
+
+ *pc = omap_read(uart, UART_RBR) & 0xff;
+ return 1;
+}
+
+static int __init omap_uart_irq(struct serial_port *port)
+{
+ struct omap_uart *uart = port->uart;
+
+ return ((uart->irq.irq > 0) ? uart->irq.irq : -1);
+}
+
+static const struct dt_irq __init *omap_uart_dt_irq(struct serial_port *port)
+{
+ struct omap_uart *uart = port->uart;
+
+ return &uart->irq;
+}
+
+static struct uart_driver __read_mostly omap_uart_driver = {
+ .init_preirq = omap_uart_init_preirq,
+ .init_postirq = omap_uart_init_postirq,
+ .endboot = NULL,
+ .suspend = omap_uart_suspend,
+ .resume = omap_uart_resume,
+ .tx_ready = omap_uart_tx_ready,
+ .putc = omap_uart_putc,
+ .getc = omap_uart_getc,
+ .irq = omap_uart_irq,
+ .dt_irq_get = omap_uart_dt_irq,
+};
+
+static int __init omap_uart_init(struct dt_device_node *dev,
+ const void *data)
+{
+ const char *config = data;
+ struct omap_uart *uart;
+ u32 clkspec;
+ int res;
+ u64 addr, size;
+
+ if ( strcmp(config, "") )
+ early_printk("WARNING: UART configuration is not supported\n");
+
+ uart = &omap_com;
+
+ res = dt_property_read_u32(dev, "clock-frequency", &clkspec);
+ if ( res )
+ {
+ early_printk("omap-uart: Unable to retrieve the clock frequency\n");
+ return -EINVAL;
+ }
+
+ uart->clock_hz = clkspec;
+ uart->baud = 115200;
+ uart->data_bits = 8;
+ uart->parity = UART_PARITY_NONE;
+ uart->stop_bits = 1;
+
+ res = dt_device_get_address(dev, 0, &addr, &size);
+ if ( res )
+ {
+ early_printk("omap-uart: Unable to retrieve the base"
+ " address of the UART\n");
+ return res;
+ }
+
+ uart->regs = ioremap_attr(addr, size, PAGE_HYPERVISOR_NOCACHE);
+ if ( !uart->regs )
+ {
+ early_printk("omap-uart: Unable to map the UART memory\n");
+ return -ENOMEM;
+ }
+
+ res = dt_device_get_irq(dev, 0, &uart->irq);
+ if ( res )
+ {
+ early_printk("omap-uart: Unable to retrieve the IRQ\n");
+ return res;
+ }
+
+ /* Register with generic serial driver */
+ serial_register_uart(SERHND_DTUART, &omap_uart_driver, uart);
+
+ dt_device_set_used_by(dev, DOMID_XEN);
+
+ return 0;
+}
+
+static const char const *omap_uart_dt_compat[] __initdata =
+{
+ "ti,omap4-uart",
+ NULL
+};
+
+DT_DEVICE_START(omap_uart, "OMAP UART", DEVICE_SERIAL)
+ .compatible = omap_uart_dt_compat,
+ .init = omap_uart_init,
+DT_DEVICE_END
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/xen/8250-uart.h b/xen/include/xen/8250-uart.h
index 33daa6d..71970a1 100644
--- a/xen/include/xen/8250-uart.h
+++ b/xen/include/xen/8250-uart.h
@@ -58,19 +58,51 @@
#define UART_FCR_CLRX 0x02 /* clear Rx FIFO */
#define UART_FCR_CLTX 0x04 /* clear Tx FIFO */
#define UART_FCR_DMA 0x10 /* enter DMA mode */
+
#define UART_FCR_TRG1 0x00 /* Rx FIFO trig lev 1 */
#define UART_FCR_TRG4 0x40 /* Rx FIFO trig lev 4 */
#define UART_FCR_TRG8 0x80 /* Rx FIFO trig lev 8 */
#define UART_FCR_TRG14 0xc0 /* Rx FIFO trig lev 14 */
+/*
+ * Note: The FIFO trigger levels are chip specific:
+ * RX:76 = 00 01 10 11 TX:54 = 00 01 10 11
+ * PC16550D: 1 4 8 14 xx xx xx xx
+ * TI16C550A: 1 4 8 14 xx xx xx xx
+ * TI16C550C: 1 4 8 14 xx xx xx xx
+ * ST16C550: 1 4 8 14 xx xx xx xx
+ * ST16C650: 8 16 24 28 16 8 24 30 PORT_16650V2
+ * NS16C552: 1 4 8 14 xx xx xx xx
+ * ST16C654: 8 16 56 60 8 16 32 56 PORT_16654
+ * TI16C750: 1 16 32 56 xx xx xx xx PORT_16750
+ * TI16C752: 8 16 56 60 8 16 32 56
+ * Tegra: 1 4 8 14 16 8 4 1 PORT_TEGRA
+ */
+#define UART_FCR_R_TRIG_00 0x00
+#define UART_FCR_R_TRIG_01 0x40
+#define UART_FCR_R_TRIG_10 0x80
+#define UART_FCR_R_TRIG_11 0xc0
+#define UART_FCR_T_TRIG_00 0x00
+#define UART_FCR_T_TRIG_01 0x10
+#define UART_FCR_T_TRIG_10 0x20
+#define UART_FCR_T_TRIG_11 0x30
+
/* Line Control Register */
#define UART_LCR_DLAB 0x80 /* Divisor Latch Access */
+/*
+ * Access to some registers depends on register access / configuration
+ * mode.
+ */
+#define UART_LCR_CONF_MODE_A UART_LCR_DLAB /* Configuration mode A */
+#define UART_LCR_CONF_MODE_B 0xBF /* Configuration mode B */
+
/* Modem Control Register */
-#define UART_MCR_DTR 0x01 /* Data Terminal Ready */
-#define UART_MCR_RTS 0x02 /* Request to Send */
-#define UART_MCR_OUT2 0x08 /* OUT2: interrupt mask */
+#define UART_MCR_TCRTLR 0x40 /* Access TCR/TLR (TI16C752, EFR[4]=1) */
#define UART_MCR_LOOP 0x10 /* Enable loopback test mode */
+#define UART_MCR_OUT2 0x08 /* Out2 complement */
+#define UART_MCR_RTS 0x02 /* RTS complement */
+#define UART_MCR_DTR 0x01 /* DTR complement */
/* Line Status Register */
#define UART_LSR_DR 0x01 /* Data ready */
@@ -96,6 +128,27 @@
#define RESUME_DELAY MILLISECS(10)
#define RESUME_RETRIES 100
+/* Enhanced feature register */
+#define UART_OMAP_EFR 0x02
+
+#define UART_OMAP_EFR_ECB 0x10 /* Enhanced control bit */
+
+/* Mode definition register 1 */
+#define UART_OMAP_MDR1 0x08
+
+/*
+ * These are the definitions for the MDR1 register
+ */
+#define UART_OMAP_MDR1_16X_MODE 0x00 /* UART 16x mode */
+#define UART_OMAP_MDR1_DISABLE 0x07 /* Disable (default state) */
+
+/* Supplementary control register */
+#define UART_OMAP_SCR 0x10
+
+/* SCR register bitmasks */
+#define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK (1 << 7)
+
+
#endif /* __XEN_8250_UART_H__ */
/*
diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
index 5a2a5c6..ab21a81 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -300,6 +300,12 @@ const void *dt_get_property(const struct dt_device_node
*np,
const char *name, u32 *lenp);
/**
+ * dt_property_read_u32 - Helper to read a u32 property.
+ */
+int dt_property_read_u32(const struct dt_device_node *np,
+ const char *name, u32 *out_value);
+
+/**
* Checks if the given "compat" string matches one of the strings in
* the device's "compatible" property
*/
--
1.8.1.4
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