cavium: generic 8250 serial driver changes
We are in the process of preparing kernel support for the Cavium
Networks OCTEON processor for inclusion in the main-line kernel
sources. The main (perhaps only) place this affects the non-processor
specific parts of the kernel is in the 8250 serial driver. The OCTEON
contains several on-chip UARTS that require processor specific register
access code.
It is our thought that rather than pollute the 8250 driver with yet
another one-off register access method, we would change the driver to
access the UART registers via function pointers setup at driver
initialization time. A side benefit of this is that it makes it easy
to move some of the existing register access code back to platform
specific files.
Patch 1 makes the register access functions replaceable.
Patch 2 is a completely untested prototype that moves the UPIO_TSI
back to platform specific code.
This part tested on 2.6.27-rc8 on i686.
In order to use Cavium OCTEON specific serial i/o drivers, we first patch
the 8250 driver to use replaceable i/o functions.
Signed-off-by: David Daney <ddaney@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Tomaso Paoletti <tpaoletti@xxxxxxxxxxxxxxxxxx>
---
drivers/serial/8250.c | 185 +++++++++++++++++++++++++++++--------------
include/linux/serial_8250.h | 2 +
include/linux/serial_core.h | 2 +
3 files changed, 131 insertions(+), 58 deletions(-)
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 9ccc563..02771d6 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -288,16 +288,16 @@ static const u8 au_io_out_map[] = {
};
/* sane hardware needs no mapping */
-static inline int map_8250_in_reg(struct uart_8250_port *up, int offset)
+static inline int map_8250_in_reg(struct uart_port *p, int offset)
{
- if (up->port.iotype != UPIO_AU)
+ if (p->iotype != UPIO_AU)
return offset;
return au_io_in_map[offset];
}
-static inline int map_8250_out_reg(struct uart_8250_port *up, int offset)
+static inline int map_8250_out_reg(struct uart_port *p, int offset)
{
- if (up->port.iotype != UPIO_AU)
+ if (p->iotype != UPIO_AU)
return offset;
return au_io_out_map[offset];
}
@@ -326,16 +326,16 @@ static const u8
[UART_SCR] = 0x2c
};
-static inline int map_8250_in_reg(struct uart_8250_port *up, int offset)
+static inline int map_8250_in_reg(struct uart_port *p, int offset)
{
- if (up->port.iotype != UPIO_RM9000)
+ if (p->iotype != UPIO_RM9000)
return offset;
return regmap_in[offset];
}
-static inline int map_8250_out_reg(struct uart_8250_port *up, int offset)
+static inline int map_8250_out_reg(struct uart_port *p, int offset)
{
- if (up->port.iotype != UPIO_RM9000)
+ if (p->iotype != UPIO_RM9000)
return offset;
return regmap_out[offset];
}
@@ -348,108 +348,170 @@ static inline int map_8250_out_reg(struct uart_8250_port *up, int offset)
#endif
-static unsigned int serial_in(struct uart_8250_port *up, int offset)
+static unsigned int hub6_serial_in_fn(struct uart_port *p, int offset)
{
- unsigned int tmp;
- offset = map_8250_in_reg(up, offset) << up->port.regshift;
+ offset = map_8250_in_reg(p, offset) << p->regshift;
+ outb(p->hub6 - 1 + offset, p->iobase);
+ return inb(p->iobase + 1);
+}
- switch (up->port.iotype) {
- case UPIO_HUB6:
- outb(up->port.hub6 - 1 + offset, up->port.iobase);
- return inb(up->port.iobase + 1);
+static void hub6_serial_out_fn(struct uart_port *p, int offset, int value)
+{
+ offset = map_8250_out_reg(p, offset) << p->regshift;
+ outb(p->hub6 - 1 + offset, p->iobase);
+ outb(value, p->iobase + 1);
+}
- case UPIO_MEM:
- case UPIO_DWAPB:
- return readb(up->port.membase + offset);
+static unsigned int mem_serial_in_fn(struct uart_port *p, int offset)
+{
+ offset = map_8250_in_reg(p, offset) << p->regshift;
+ return readb(p->membase + offset);
+}
- case UPIO_RM9000:
- case UPIO_MEM32:
- return readl(up->port.membase + offset);
+static void mem_serial_out_fn(struct uart_port *p, int offset, int value)
+{
+ offset = map_8250_out_reg(p, offset) << p->regshift;
+ writeb(value, p->membase + offset);
+}
+
+static void mem32_serial_out_fn(struct uart_port *p, int offset, int value)
+{
+ offset = map_8250_out_reg(p, offset) << p->regshift;
+ writel(value, p->membase + offset);
+}
+
+static unsigned int mem32_serial_in_fn(struct uart_port *p, int offset)
+{
+ offset = map_8250_in_reg(p, offset) << p->regshift;
+ return readl(p->membase + offset);
+}
#ifdef CONFIG_SERIAL_8250_AU1X00
- case UPIO_AU:
- return __raw_readl(up->port.membase + offset);
+static unsigned int au_serial_in_fn(struct uart_port *p, int offset)
+{
+ offset = map_8250_in_reg(p, offset) << p->regshift;
+ return __raw_readl(p->membase + offset);
+}
+
+static void au_serial_out_fn(struct uart_port *p, int offset, int value)
+{
+ offset = map_8250_out_reg(p, offset) << p->regshift;
+ __raw_writel(value, p->membase + offset);
+}
#endif
- case UPIO_TSI:
- if (offset == UART_IIR) {
- tmp = readl(up->port.membase + (UART_IIR & ~3));
- return (tmp >> 16) & 0xff; /* UART_IIR % 4 == 2 */
- } else
- return readb(up->port.membase + offset);
+static unsigned int tsi_serial_in_fn(struct uart_port *p, int offset)
+{
+ unsigned int tmp;
+ offset = map_8250_in_reg(p, offset) << p->regshift;
+ if (offset == UART_IIR) {
+ tmp = readl(p->membase + (UART_IIR & ~3));
+ return (tmp >> 16) & 0xff; /* UART_IIR % 4 == 2 */
+ } else
+ return readb(p->membase + offset);
+}
- default:
- return inb(up->port.iobase + offset);
- }
+static void tsi_serial_out_fn(struct uart_port *p, int offset, int value)
+{
+ offset = map_8250_out_reg(p, offset) << p->regshift;
+ if (!((offset == UART_IER) && (value & UART_IER_UUE)))
+ writeb(value, p->membase + offset);
}
-static void
-serial_out(struct uart_8250_port *up, int offset, int value)
+static void dwapb_serial_out_fn(struct uart_port *p, int offset, int value)
{
- /* Save the offset before it's remapped */
int save_offset = offset;
- offset = map_8250_out_reg(up, offset) << up->port.regshift;
+ offset = map_8250_out_reg(p, offset) << p->regshift;
+ /* Save the LCR value so it can be re-written when a
+ * Busy Detect interrupt occurs. */
+ if (save_offset == UART_LCR) {
+ struct uart_8250_port *up = (struct uart_8250_port *)p;
+ up->lcr = value;
+ }
+ writeb(value, p->membase + offset);
+ /* Read the IER to ensure any interrupt is cleared before
+ * returning from ISR. */
+ if (save_offset == UART_TX || save_offset == UART_IER)
+ value = p->serial_in_fn(p, UART_IER);
+}
- switch (up->port.iotype) {
+static unsigned int io_serial_in_fn(struct uart_port *p, int offset)
+{
+ offset = map_8250_in_reg(p, offset) << p->regshift;
+ return inb(p->iobase + offset);
+}
+
+static void io_serial_out_fn(struct uart_port *p, int offset, int value)
+{
+ offset = map_8250_out_reg(p, offset) << p->regshift;
+ outb(value, p->iobase + offset);
+}
+
+static void set_io_fns_from_upio(struct uart_port *p)
+{
+ switch (p->iotype) {
case UPIO_HUB6:
- outb(up->port.hub6 - 1 + offset, up->port.iobase);
- outb(value, up->port.iobase + 1);
+ p->serial_in_fn = hub6_serial_in_fn;
+ p->serial_out_fn = hub6_serial_out_fn;
break;
case UPIO_MEM:
- writeb(value, up->port.membase + offset);
+ p->serial_in_fn = mem_serial_in_fn;
+ p->serial_out_fn = mem_serial_out_fn;
break;
case UPIO_RM9000:
case UPIO_MEM32:
- writel(value, up->port.membase + offset);
+ p->serial_in_fn = mem32_serial_in_fn;
+ p->serial_out_fn = mem32_serial_out_fn;
break;
#ifdef CONFIG_SERIAL_8250_AU1X00
case UPIO_AU:
- __raw_writel(value, up->port.membase + offset);
+ p->serial_in_fn = au_serial_in_fn;
+ p->serial_out_fn = au_serial_out_fn;
break;
#endif
case UPIO_TSI:
- if (!((offset == UART_IER) && (value & UART_IER_UUE)))
- writeb(value, up->port.membase + offset);
+ p->serial_in_fn = tsi_serial_in_fn;
+ p->serial_out_fn = tsi_serial_out_fn;
break;
case UPIO_DWAPB:
- /* Save the LCR value so it can be re-written when a
- * Busy Detect interrupt occurs. */
- if (save_offset == UART_LCR)
- up->lcr = value;
- writeb(value, up->port.membase + offset);
- /* Read the IER to ensure any interrupt is cleared before
- * returning from ISR. */
- if (save_offset == UART_TX || save_offset == UART_IER)
- value = serial_in(up, UART_IER);
+ p->serial_in_fn = mem_serial_in_fn;
+ p->serial_out_fn = dwapb_serial_out_fn;
break;
default:
- outb(value, up->port.iobase + offset);
+ p->serial_in_fn = io_serial_in_fn;
+ p->serial_out_fn = io_serial_out_fn;
+ break;
}
}
static void
serial_out_sync(struct uart_8250_port *up, int offset, int value)
{
- switch (up->port.iotype) {
+ struct uart_port *p = &up->port;
+ switch (p->iotype) {
case UPIO_MEM:
case UPIO_MEM32:
#ifdef CONFIG_SERIAL_8250_AU1X00
case UPIO_AU:
#endif
case UPIO_DWAPB:
- serial_out(up, offset, value);
- serial_in(up, UART_LCR); /* safe, no side-effects */
+ p->serial_out_fn(p, offset, value);
+ p->serial_in_fn(p, UART_LCR); /* safe, no side-effects */
break;
default:
- serial_out(up, offset, value);
+ p->serial_out_fn(p, offset, value);
}
}
+#define serial_in(up, offset) \
+ (up->port.serial_in_fn(&(up)->port, (offset)))
+#define serial_out(up, offset, value) \
+ (up->port.serial_out_fn(&(up)->port, (offset), (value)))
/*
* We used to support using pause I/O for certain machines. We
* haven't supported this for a while, but just in case it's badly
@@ -2511,6 +2573,7 @@ static void __init serial8250_isa_init_ports(void)
up->port.membase = old_serial_port[i].iomem_base;
up->port.iotype = old_serial_port[i].io_type;
up->port.regshift = old_serial_port[i].iomem_reg_shift;
+ set_io_fns_from_upio(&up->port);
if (share_irqs)
up->port.flags |= UPF_SHARE_IRQ;
}
@@ -2912,6 +2975,12 @@ int serial8250_register_port(struct uart_port *port)
uart->port.private_data = port->private_data;
if (port->dev)
uart->port.dev = port->dev;
+ set_io_fns_from_upio(&uart->port);
+ /* Possibly override default I/O functions. */
+ if (port->serial_in_fn)
+ uart->port.serial_in_fn = port->serial_in_fn;
+ if (port->serial_out_fn)
+ uart->port.serial_out_fn = port->serial_out_fn;
ret = uart_add_one_port(&serial8250_reg, &uart->port);
if (ret == 0)
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index 3d37c94..eb08b04 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -28,6 +28,8 @@ struct plat_serial8250_port {
unsigned char iotype; /* UPIO_* */
unsigned char hub6;
upf_t flags; /* UPF_* flags */
+ unsigned int (*serial_in_fn)(struct uart_port *, int);
+ void (*serial_out_fn)(struct uart_port *, int, int);
};
/*
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 3b2f6c0..3a4afcf 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -243,6 +243,8 @@ struct uart_port {
spinlock_t lock; /* port lock */
unsigned int iobase; /* in/out[bwl] */
unsigned char __iomem *membase; /* read/write[bwl] */
+ unsigned int (*serial_in_fn)(struct uart_port *, int);
+ void (*serial_out_fn)(struct uart_port *, int, int);
unsigned int irq; /* irq number */
unsigned int uartclk; /* base uart clock */
unsigned int fifosize; /* tx fifo size */
