[v7] serial: 8250_dw: Add support for big-endian MMIO accesses

From: Noam Camus
Date: Tue Oct 06 2015 - 04:54:46 EST


From: Noam Camus <noamc@xxxxxxxxxx>

Add support for UPIO_MEM32BE in addition to UPIO_MEM32.
dw8250_serial_out32() extra functionality that is not part of
the 8250 core driver was moved to new function called
dw8250_check_LCR().

For big endian we use 2 new accessors similar to little endian,
called dw8250_serial_out32be() and dw8250_serial_in32be().
Both little and big endian accessors use dw8250_check_LCR()
for their dw8250_serial_out32{,be}().

In addition I added another 2 accessors inside private_data field of
uart_port. This second level accessors are set during probe in
private_data field of uart_port. Now any direct call to readl/writel
is replaced with those accessors which are endianness aware.

Last issue:
readl() for UCV and CPR will not work for port type UPIO_MEM32BE.
Instead we use the serial_in32() accessor which is initialized
properly according to endianness.

Signed-off-by: Noam Camus <noamc@xxxxxxxxxx>
---
drivers/tty/serial/8250/8250_dw.c | 72 ++++++++++++++++++++++++++++++++----
1 files changed, 64 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 06324f1..3beff92 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -63,6 +63,9 @@ struct dw8250_data {
struct clk *pclk;
struct reset_control *rst;
struct uart_8250_dma dma;
+ unsigned int (*serial_in)(void __iomem *addr);
+ void (*serial_out)(unsigned int value,
+ void __iomem *addr);
};

#define BYT_PRV_CLK 0x800
@@ -156,9 +159,9 @@ static void dw8250_serial_outq(struct uart_port *p, int offset, int value)
}
#endif /* CONFIG_64BIT */

-static void dw8250_serial_out32(struct uart_port *p, int offset, int value)
+static void dw8250_check_LCR(struct uart_port *p, int offset, int value)
{
- writel(value, p->membase + (offset << p->regshift));
+ struct dw8250_data *d = p->private_data;

/* Make sure LCR write wasn't ignored */
if (offset == UART_LCR) {
@@ -168,7 +171,8 @@ static void dw8250_serial_out32(struct uart_port *p, int offset, int value)
if ((value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR))
return;
dw8250_force_idle(p);
- writel(value, p->membase + (UART_LCR << p->regshift));
+ d->serial_out(value,
+ p->membase + (UART_LCR << p->regshift));
}
/*
* FIXME: this deadlocks if port->lock is already held
@@ -177,6 +181,22 @@ static void dw8250_serial_out32(struct uart_port *p, int offset, int value)
}
}

+static void _dw8250_serial_out32(unsigned int value, void __iomem *addr)
+{
+ writel(value, addr);
+}
+
+static unsigned int _dw8250_serial_in32(void __iomem *addr)
+{
+ return readl(addr);
+}
+
+static void dw8250_serial_out32(struct uart_port *p, int offset, int value)
+{
+ writel(value, p->membase + (offset << p->regshift));
+ dw8250_check_LCR(p, offset, value);
+}
+
static unsigned int dw8250_serial_in32(struct uart_port *p, int offset)
{
unsigned int value = readl(p->membase + (offset << p->regshift));
@@ -184,6 +204,29 @@ static unsigned int dw8250_serial_in32(struct uart_port *p, int offset)
return dw8250_modify_msr(p, offset, value);
}

+static void _dw8250_serial_out32be(unsigned int value, void __iomem *addr)
+{
+ iowrite32be(value, addr);
+}
+
+static unsigned int _dw8250_serial_in32be(void __iomem *addr)
+{
+ return ioread32be(addr);
+}
+
+static void dw8250_serial_out32be(struct uart_port *p, int offset, int value)
+{
+ iowrite32be(value, p->membase + (offset << p->regshift));
+ dw8250_check_LCR(p, offset, value);
+}
+
+static unsigned int dw8250_serial_in32be(struct uart_port *p, int offset)
+{
+ unsigned int value = ioread32be(p->membase + (offset << p->regshift));
+
+ return dw8250_modify_msr(p, offset, value);
+}
+
static int dw8250_handle_irq(struct uart_port *p)
{
struct dw8250_data *d = p->private_data;
@@ -252,7 +295,8 @@ static bool dw8250_dma_filter(struct dma_chan *chan, void *param)
static void dw8250_setup_port(struct uart_8250_port *up)
{
struct uart_port *p = &up->port;
- u32 reg = readl(p->membase + DW_UART_UCV);
+ struct dw8250_data *d = p->private_data;
+ u32 reg = d->serial_in(p->membase + DW_UART_UCV);

/*
* If the Component Version Register returns zero, we know that
@@ -264,7 +308,7 @@ static void dw8250_setup_port(struct uart_8250_port *up)
dev_dbg_ratelimited(p->dev, "Designware UART version %c.%c%c\n",
(reg >> 24) & 0xff, (reg >> 16) & 0xff, (reg >> 8) & 0xff);

- reg = readl(p->membase + DW_UART_CPR);
+ reg = d->serial_in(p->membase + DW_UART_CPR);
if (!reg)
return;

@@ -305,9 +349,19 @@ static int dw8250_probe_of(struct uart_port *p,
case 1:
break;
case 4:
- p->iotype = UPIO_MEM32;
- p->serial_in = dw8250_serial_in32;
- p->serial_out = dw8250_serial_out32;
+ p->iotype = of_device_is_big_endian(np) ?
+ UPIO_MEM32BE : UPIO_MEM32;
+ if (p->iotype == UPIO_MEM32) {
+ p->serial_in = dw8250_serial_in32;
+ p->serial_out = dw8250_serial_out32;
+ data->serial_in = _dw8250_serial_in32;
+ data->serial_out = _dw8250_serial_out32;
+ } else {
+ p->serial_in = dw8250_serial_in32be;
+ p->serial_out = dw8250_serial_out32be;
+ data->serial_in = _dw8250_serial_in32be;
+ data->serial_out = _dw8250_serial_out32be;
+ }
break;
default:
dev_err(p->dev, "unsupported reg-io-width (%u)\n", val);
@@ -487,6 +541,8 @@ static int dw8250_probe(struct platform_device *pdev)
data->dma.rx_param = data;
data->dma.tx_param = data;
data->dma.fn = dw8250_dma_filter;
+ data->serial_in = _dw8250_serial_in32;
+ data->serial_out = _dw8250_serial_out32;

uart.port.iotype = UPIO_MEM;
uart.port.serial_in = dw8250_serial_in;
--
1.7.1

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