Some platforms contain a Synopsys DesignWare APB UART that is attached
to a 32-bit APB bus where sub-word accesses are not allowed. Add a new
IO type (UPIO_DWAPB32) that performs 32 bit acccesses to the UART.
Signed-off-by: Jamie Iles <jamie.iles@xxxxxxxxxxxx>
---
drivers/serial/8250.c | 18 ++++++++++++++++--
drivers/serial/8250_early.c | 6 +++++-
drivers/serial/serial_core.c | 2 ++
include/linux/serial_core.h | 1 +
4 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index c87f7bd..b03a8c8 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -463,7 +463,12 @@ static void dwapb_serial_out(struct uart_port *p, int offset, int value)
struct uart_8250_port *up = (struct uart_8250_port *)p;
up->lcr = value;
}
- writeb(value, p->membase + offset);
+
+ if (UPIO_DWAPB == p->iotype)
+ writeb(value, p->membase + offset);
+ else
+ writel(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)
@@ -518,6 +523,11 @@ static void set_io_from_upio(struct uart_port *p)
p->serial_out = dwapb_serial_out;
break;
+ case UPIO_DWAPB32:
+ p->serial_in = mem32_serial_in;
+ p->serial_out = dwapb_serial_out;
+ break;
+
default:
p->serial_in = io_serial_in;
p->serial_out = io_serial_out;
@@ -538,6 +548,7 @@ serial_out_sync(struct uart_8250_port *up, int offset, int value)
case UPIO_AU:
#endif
case UPIO_DWAPB:
+ case UPIO_DWAPB32:
p->serial_out(p, offset, value);
p->serial_in(p, UART_LCR); /* safe, no side-effects */
break;
@@ -1574,7 +1585,8 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
handled = 1;
end = NULL;
- } else if (up->port.iotype == UPIO_DWAPB &&
+ } else if ((up->port.iotype == UPIO_DWAPB ||
+ up->port.iotype == UPIO_DWAPB32) &&
(iir & UART_IIR_BUSY) == UART_IIR_BUSY) {
/* The DesignWare APB UART has an Busy Detect (0x07)
* interrupt meaning an LCR write attempt occured while the
@@ -2444,6 +2456,7 @@ static int serial8250_request_std_resource(struct uart_8250_port *up)
case UPIO_MEM32:
case UPIO_MEM:
case UPIO_DWAPB:
+ case UPIO_DWAPB32:
if (!up->port.mapbase)
break;
@@ -2481,6 +2494,7 @@ static void serial8250_release_std_resource(struct uart_8250_port *up)
case UPIO_MEM32:
case UPIO_MEM:
case UPIO_DWAPB:
+ case UPIO_DWAPB32:
if (!up->port.mapbase)
break;
diff --git a/drivers/serial/8250_early.c b/drivers/serial/8250_early.c
index f279745..51a3497 100644
--- a/drivers/serial/8250_early.c
+++ b/drivers/serial/8250_early.c
@@ -48,7 +48,9 @@ static struct early_serial8250_device early_device;
static unsigned int __init serial_in(struct uart_port *port, int offset)
{
- if (port->iotype == UPIO_MEM)
+ if (port->iotype == UPIO_MEM32)
+ return readl(port->membase + offset);
+ else if (port->iotype == UPIO_MEM)
return readb(port->membase + offset);
else
return inb(port->iobase + offset);
@@ -56,6 +58,8 @@ static unsigned int __init serial_in(struct uart_port *port, int offset)
static void __init serial_out(struct uart_port *port, int offset, int value)
{
+ if (port->iotype == UPIO_MEM32)
+ writel(value, port->membase + offset);
if (port->iotype == UPIO_MEM)
writeb(value, port->membase + offset);
else
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index fa4f170..71ce227 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -2142,6 +2142,7 @@ uart_report_port(struct uart_driver *drv, struct uart_port *port)
case UPIO_AU:
case UPIO_TSI:
case UPIO_DWAPB:
+ case UPIO_DWAPB32:
snprintf(address, sizeof(address),
"MMIO 0x%llx", (unsigned long long)port->mapbase);
break;
@@ -2555,6 +2556,7 @@ int uart_match_port(struct uart_port *port1, struct uart_port *port2)
case UPIO_AU:
case UPIO_TSI:
case UPIO_DWAPB:
+ case UPIO_DWAPB32:
return (port1->mapbase == port2->mapbase);
}
return 0;
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index d40db83..6eea6cf 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -289,6 +289,7 @@ struct uart_port {
#define UPIO_TSI (5) /* Tsi108/109 type IO */
#define UPIO_DWAPB (6) /* DesignWare APB UART */
#define UPIO_RM9000 (7) /* RM9000 type IO */
+#define UPIO_DWAPB32 (8) /* DesignWare APB UART (32 bit accesses) */
unsigned int read_status_mask; /* driver specific */
unsigned int ignore_status_mask; /* driver specific */
--
1.6.5.4
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