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[PATCH 2/4] 8250: Serial driver changes to support future Cavium OCTEON

To: linux-serial@vger.kernel.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk
Subject: [PATCH 2/4] 8250: Serial driver changes to support future Cavium OCTEON serial patches.
From: David Daney <ddaney@caviumnetworks.com>
Date: Mon, 1 Dec 2008 15:49:26 -0800
Cc: linux-mips@linux-mips.org, David Daney <ddaney@caviumnetworks.com>, Tomaso Paoletti <tpaoletti@caviumnetworks.com>
In-reply-to: <4934774E.6080805@caviumnetworks.com>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <4934774E.6080805@caviumnetworks.com>
Sender: linux-mips-bounce@linux-mips.org
In order to use Cavium OCTEON specific serial i/o drivers, we first
patch the 8250 driver to use replaceable I/O functions.  Compatible
I/O functions are added for existing iotypeS.

An added benefit of this change is that it makes it easy to factor
some of the existing special cases out to board/SOC specific support
code.

The alternative is to load up 8250.c with a bunch of OCTEON specific
iotype code and bug work-arounds.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Tomaso Paoletti <tpaoletti@caviumnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/serial/8250.c       |  194 ++++++++++++++++++++++++++++++-------------
 include/linux/serial_8250.h |    2 +
 include/linux/serial_core.h |    2 +
 3 files changed, 140 insertions(+), 58 deletions(-)

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 8e28750..849af9d 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -303,16 +303,16 @@ 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];
 }
@@ -341,16 +341,16 @@ 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];
 }
@@ -363,108 +363,170 @@ 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(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(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(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(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(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(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(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(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(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(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(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(p, UART_IER);
+}
 
-       switch (up->port.iotype) {
+static unsigned int io_serial_in(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(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_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 = hub6_serial_in;
+               p->serial_out = hub6_serial_out;
                break;
 
        case UPIO_MEM:
-               writeb(value, up->port.membase + offset);
+               p->serial_in = mem_serial_in;
+               p->serial_out = mem_serial_out;
                break;
 
        case UPIO_RM9000:
        case UPIO_MEM32:
-               writel(value, up->port.membase + offset);
+               p->serial_in = mem32_serial_in;
+               p->serial_out = mem32_serial_out;
                break;
 
 #ifdef CONFIG_SERIAL_8250_AU1X00
        case UPIO_AU:
-               __raw_writel(value, up->port.membase + offset);
+               p->serial_in = au_serial_in;
+               p->serial_out = au_serial_out;
                break;
 #endif
        case UPIO_TSI:
-               if (!((offset == UART_IER) && (value & UART_IER_UUE)))
-                       writeb(value, up->port.membase + offset);
+               p->serial_in = tsi_serial_in;
+               p->serial_out = tsi_serial_out;
                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 = mem_serial_in;
+               p->serial_out = dwapb_serial_out;
                break;
 
        default:
-               outb(value, up->port.iobase + offset);
+               p->serial_in = io_serial_in;
+               p->serial_out = io_serial_out;
+               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(p, offset, value);
+               p->serial_in(p, UART_LCR);      /* safe, no side-effects */
                break;
        default:
-               serial_out(up, offset, value);
+               p->serial_out(p, offset, value);
        }
 }
 
+#define serial_in(up, offset)          \
+       (up->port.serial_in(&(up)->port, (offset)))
+#define serial_out(up, offset, value)  \
+       (up->port.serial_out(&(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
@@ -2576,6 +2638,7 @@ 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_from_upio(&up->port);
                if (share_irqs)
                        up->port.flags |= UPF_SHARE_IRQ;
        }
@@ -2769,6 +2832,13 @@ int __init early_serial_setup(struct uart_port *port)
        p->flags        = port->flags;
        p->mapbase      = port->mapbase;
        p->private_data = port->private_data;
+
+       set_io_from_upio(p);
+       if (port->serial_in)
+               p->serial_in = port->serial_in;
+       if (port->serial_out)
+               p->serial_out = port->serial_out;
+
        return 0;
 }
 
@@ -2833,6 +2903,8 @@ static int __devinit serial8250_probe(struct 
platform_device *dev)
                port.mapbase            = p->mapbase;
                port.hub6               = p->hub6;
                port.private_data       = p->private_data;
+               port.serial_in          = p->serial_in;
+               port.serial_out         = p->serial_out;
                port.dev                = &dev->dev;
                if (share_irqs)
                        port.flags |= UPF_SHARE_IRQ;
@@ -2986,6 +3058,12 @@ 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_from_upio(&uart->port);
+               /* Possibly override default I/O functions.  */
+               if (port->serial_in)
+                       uart->port.serial_in = port->serial_in;
+               if (port->serial_out)
+                       uart->port.serial_out = port->serial_out;
 
                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..77d83d9 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)(struct uart_port *, int);
+       void            (*serial_out)(struct uart_port *, int, int);
 };
 
 /*
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 4e4f127..2d22c67 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -246,6 +246,8 @@ struct uart_port {
        spinlock_t              lock;                   /* port lock */
        unsigned long           iobase;                 /* in/out[bwl] */
        unsigned char __iomem   *membase;               /* read/write[bwl] */
+       unsigned int            (*serial_in)(struct uart_port *, int);
+       void                    (*serial_out)(struct uart_port *, int, int);
        unsigned int            irq;                    /* irq number */
        unsigned int            uartclk;                /* base uart clock */
        unsigned int            fifosize;               /* tx fifo size */
-- 
1.5.6.5


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