[ARM] 5541/1: serial/amba-pl011.c: add support for the modified port found in Nomadik

The Nomadik 8815 SoC has a slightly modified version of the PL011 block.
The patch uses the different ID value as a key to select a vendor
structure that is used to keep track of the differences, as suggested
by Russell King.

Signed-off-by: Alessandro Rubini <rubini@unipv.it>
Acked-by: Andrea Gallo <andrea.gallo@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 30 insertions, 3 deletions

diff --git a/drivers/serial/amba-pl011.c b/drivers/serial/amba-pl011.c
index 4cfa1eb26892..8c5bda27736c 100644
--- a/drivers/serial/amba-pl011.c
+++ b/drivers/serial/amba-pl011.c
@@ -70,6 +70,23 @@ struct uart_amba_port {
         struct clk              *clk;
         unsigned int            im;     /* interrupt mask */
         unsigned int            old_status;
+        unsigned int            ifls;   /* vendor-specific */
+};
+
+/* There is by now at least one vendor with differing details, so handle it */
+struct vendor_data {
+        unsigned int            ifls;
+        unsigned int            fifosize;
+};
+
+static struct vendor_data vendor_arm = {
+        .ifls                   = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
+        .fifosize               = 16,
+};
+
+static struct vendor_data vendor_st = {
+        .ifls                   = UART011_IFLS_RX_HALF|UART011_IFLS_TX_HALF,
+        .fifosize               = 64,
 };
 
 static void pl011_stop_tx(struct uart_port *port)
@@ -360,8 +377,7 @@ static int pl011_startup(struct uart_port *port)
         if (retval)
                 goto clk_dis;
 
-        writew(UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
-               uap->port.membase + UART011_IFLS);
+        writew(uap->ifls, uap->port.membase + UART011_IFLS);
 
         /*
          * Provoke TX FIFO interrupt into asserting.
@@ -732,6 +748,7 @@ static struct uart_driver amba_reg = {
 static int pl011_probe(struct amba_device *dev, struct amba_id *id)
 {
         struct uart_amba_port *uap;
+        struct vendor_data *vendor = id->data;
         void __iomem *base;
         int i, ret;
 
@@ -762,12 +779,13 @@ static int pl011_probe(struct amba_device *dev, struct amba_id *id)
                 goto unmap;
         }
 
+        uap->ifls = vendor->ifls;
         uap->port.dev = &dev->dev;
         uap->port.mapbase = dev->res.start;
         uap->port.membase = base;
         uap->port.iotype = UPIO_MEM;
         uap->port.irq = dev->irq[0];
-        uap->port.fifosize = 16;
+        uap->port.fifosize = vendor->fifosize;
         uap->port.ops = &amba_pl011_pops;
         uap->port.flags = UPF_BOOT_AUTOCONF;
         uap->port.line = i;
@@ -812,6 +830,12 @@ static struct amba_id pl011_ids[] __initdata = {
         {
                 .id     = 0x00041011,
                 .mask   = 0x000fffff,
+                .data   = &vendor_arm,
+        },
+        {
+                .id     = 0x00380802,
+                .mask   = 0x00ffffff,
+                .data   = &vendor_st,
         },
         { 0, 0 },
 };
diff --git a/include/linux/amba/serial.h b/include/linux/amba/serial.h
index 48ee32a18ac5..42949e210cb8 100644
--- a/include/linux/amba/serial.h
+++ b/include/linux/amba/serial.h
@@ -114,6 +114,9 @@
 #define UART011_IFLS_TX4_8      (2 << 0)
 #define UART011_IFLS_TX6_8      (3 << 0)
 #define UART011_IFLS_TX7_8      (4 << 0)
+/* special values for ST vendor with deeper fifo */
+#define UART011_IFLS_RX_HALF    (5 << 3)
+#define UART011_IFLS_TX_HALF    (5 << 0)
 
 #define UART011_OEIM            (1 << 10)       /* overrun error interrupt mask */
 #define UART011_BEIM            (1 << 9)        /* break error interrupt mask */