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8250: add a UPIO_DWAPB32 for 32 bit accesses 

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.

v2:
	- don't test for 32 bit in the output fast path, provide a
	  separate dwabp32_serial_out() function. Refactor
	  dwabp_serial_out() so that we can reuse the LCR saving
	  code.
v3:
	- rebased on top of "8250: use container_of() instead of
	  casting"

Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Jamie Iles 2010-12-01 23:39:36 +00:00 committed by Greg Kroah-Hartman
parent 49d5741be2
commit a3ae0fc34f
3 changed files with 42 additions and 12 deletions
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51
drivers/serial/8250.c
View File

@ -454,22 +454,40 @@ static void tsi_serial_out(struct uart_port *p, int offset, int value)
writeb(value, p->membase + offset);
}
/* Save the LCR value so it can be re-written when a Busy Detect IRQ occurs. */
static inline void dwapb_save_out_value(struct uart_port *p, int offset,
int value)
{
struct uart_8250_port *up =
container_of(p, struct uart_8250_port, port);
if (offset == UART_LCR)
up->lcr = value;
}
/* Read the IER to ensure any interrupt is cleared before returning from ISR. */
static inline void dwapb_check_clear_ier(struct uart_port *p, int offset)
{
if (offset == UART_TX || offset == UART_IER)
p->serial_in(p, UART_IER);
}
static void dwapb_serial_out(struct uart_port *p, int offset, int value)
{
int save_offset = offset;
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 =
container_of(p, struct uart_8250_port, port);
up->lcr = value;
}
dwapb_save_out_value(p, save_offset, 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);
dwapb_check_clear_ier(p, save_offset);
}
static void dwapb32_serial_out(struct uart_port *p, int offset, int value)
{
int save_offset = offset;
offset = map_8250_out_reg(p, offset) << p->regshift;
dwapb_save_out_value(p, save_offset, value);
writel(value, p->membase + offset);
dwapb_check_clear_ier(p, save_offset);
}
static unsigned int io_serial_in(struct uart_port *p, int offset)
@ -520,6 +538,11 @@ 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 = dwapb32_serial_out;
break;
default:
p->serial_in = io_serial_in;
p->serial_out = io_serial_out;
@ -538,6 +561,7 @@ serial_out_sync(struct uart_8250_port *up, int offset, int value)
case UPIO_MEM32:
case UPIO_AU:
case UPIO_DWAPB:
case UPIO_DWAPB32:
p->serial_out(p, offset, value);
p->serial_in(p, UART_LCR); /* safe, no side-effects */
break;
@ -1587,7 +1611,8 @@ 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
@ -2492,6 +2517,7 @@ 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;
@ -2529,6 +2555,7 @@ 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;

2
drivers/serial/serial_core.c
View File

@ -2135,6 +2135,7 @@ 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;

1
include/linux/serial_core.h
View File

@ -314,6 +314,7 @@ 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 */