... in favor of having what so far was called tx_empty() return the
amount of space available.
Note that in the pl011.c case, original code and comment disagreed, and
I picked the conservative value for it''s ->tx_ready()
handler''s return
value.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/drivers/char/ehci-dbgp.c
+++ b/xen/drivers/char/ehci-dbgp.c
@@ -1204,7 +1204,7 @@ static void ehci_dbgp_putc(struct serial
ehci_dbgp_flush(port);
}
-static int ehci_dbgp_tx_empty(struct serial_port *port)
+static unsigned int ehci_dbgp_tx_ready(struct serial_port *port)
{
struct ehci_dbgp *dbgp = port->uart;
@@ -1219,11 +1219,8 @@ static int ehci_dbgp_tx_empty(struct ser
if ( dbgp->state != dbgp_idle && dbgp->out.chunk >=
DBGP_MAX_PACKET )
return 0;
- port->tx_fifo_size = DBGP_MAX_PACKET - dbgp->out.chunk;
- if ( dbgp->state == dbgp_idle )
- port->tx_fifo_size += DBGP_MAX_PACKET;
-
- return 1;
+ return DBGP_MAX_PACKET - dbgp->out.chunk +
+ (dbgp->state == dbgp_idle) * DBGP_MAX_PACKET;
}
static int ehci_dbgp_getc(struct serial_port *port, char *pc)
@@ -1347,7 +1344,6 @@ static void __init ehci_dbgp_init_preirq
if ( ehci_dbgp_setup_preirq(dbgp) )
ehci_dbgp_status(dbgp, "ehci_dbgp_init_preirq complete");
- port->tx_fifo_size = DBGP_MAX_PACKET;
dbgp->lock = &port->tx_lock;
}
@@ -1448,7 +1444,7 @@ static struct uart_driver __read_mostly
.endboot = ehci_dbgp_endboot,
.suspend = ehci_dbgp_suspend,
.resume = ehci_dbgp_resume,
- .tx_empty = ehci_dbgp_tx_empty,
+ .tx_ready = ehci_dbgp_tx_ready,
.putc = ehci_dbgp_putc,
.flush = ehci_dbgp_flush,
.getc = ehci_dbgp_getc
--- a/xen/drivers/char/ns16550.c
+++ b/xen/drivers/char/ns16550.c
@@ -38,7 +38,7 @@ string_param("com1", opt_com1);
string_param("com2", opt_com2);
static struct ns16550 {
- int baud, clock_hz, data_bits, parity, stop_bits, irq;
+ int baud, clock_hz, data_bits, parity, stop_bits, fifo_size, irq;
unsigned long io_base; /* I/O port or memory-mapped I/O address. */
char __iomem *remapped_io_base; /* Remapped virtual address of MMIO. */
/* UART with IRQ line: interrupt-driven I/O. */
@@ -185,10 +185,11 @@ static void ns16550_poll(void *data)
#endif
}
-static int ns16550_tx_empty(struct serial_port *port)
+static unsigned int ns16550_tx_ready(struct serial_port *port)
{
struct ns16550 *uart = port->uart;
- return !!(ns_read_reg(uart, LSR) & LSR_THRE);
+
+ return ns_read_reg(uart, LSR) & LSR_THRE ? uart->fifo_size : 0;
}
static void ns16550_putc(struct serial_port *port, char c)
@@ -288,7 +289,7 @@ static void __init ns16550_init_preirq(s
/* Check this really is a 16550+. Otherwise we have no FIFOs. */
if ( ((ns_read_reg(uart, IIR) & 0xc0) == 0xc0) &&
((ns_read_reg(uart, FCR) & FCR_TRG14) == FCR_TRG14) )
- port->tx_fifo_size = 16;
+ uart->fifo_size = 16;
}
static void ns16550_setup_postirq(struct ns16550 *uart)
@@ -321,7 +322,7 @@ static void __init ns16550_init_postirq(
/* Calculate time to fill RX FIFO and/or empty TX FIFO for polling. */
bits = uart->data_bits + uart->stop_bits + !!uart->parity;
uart->timeout_ms = max_t(
- unsigned int, 1, (bits * port->tx_fifo_size * 1000) /
uart->baud);
+ unsigned int, 1, (bits * uart->fifo_size * 1000) / uart->baud);
if ( uart->irq > 0 )
{
@@ -388,7 +389,7 @@ static struct uart_driver __read_mostly
.endboot = ns16550_endboot,
.suspend = ns16550_suspend,
.resume = ns16550_resume,
- .tx_empty = ns16550_tx_empty,
+ .tx_ready = ns16550_tx_ready,
.putc = ns16550_putc,
.getc = ns16550_getc,
.irq = ns16550_irq
@@ -642,6 +643,8 @@ void __init ns16550_init(int index, stru
uart->stop_bits = defaults->stop_bits;
uart->irq = defaults->irq;
uart->io_base = defaults->io_base;
+ /* Default is no transmit FIFO. */
+ uart->fifo_size = 1;
ns16550_parse_port_config(uart, (index == 0) ? opt_com1 : opt_com2);
}
--- a/xen/drivers/char/pl011.c
+++ b/xen/drivers/char/pl011.c
@@ -156,9 +156,6 @@ static void __init pl011_init_preirq(str
/* Enable the UART for RX and TX; no flow ctrl */
uart->regs[CR] = RXE | TXE | UARTEN;
-
- /* Tell the serial framework about our fine 156-character FIFO */
- port->tx_fifo_size = 16;
}
static void __init pl011_init_postirq(struct serial_port *port)
@@ -192,10 +189,10 @@ static void pl011_resume(struct serial_p
BUG(); // XXX
}
-static int pl011_tx_empty(struct serial_port *port)
+static unsigned int pl011_tx_ready(struct serial_port *port)
{
struct pl011 *uart = port->uart;
- return !!(uart->regs[FR] & TXFE);
+ return uart->regs[FR] & TXFE ? 16 : 0;
}
static void pl011_putc(struct serial_port *port, char c)
@@ -227,7 +224,7 @@ static struct uart_driver __read_mostly
.endboot = NULL,
.suspend = pl011_suspend,
.resume = pl011_resume,
- .tx_empty = pl011_tx_empty,
+ .tx_ready = pl011_tx_ready,
.putc = pl011_putc,
.getc = pl011_getc,
.irq = pl011_irq
--- a/xen/drivers/char/serial.c
+++ b/xen/drivers/char/serial.c
@@ -59,7 +59,7 @@ void serial_rx_interrupt(struct serial_p
void serial_tx_interrupt(struct serial_port *port, struct cpu_user_regs *regs)
{
- int i;
+ unsigned int i, n;
unsigned long flags;
local_irq_save(flags);
@@ -71,23 +71,20 @@ void serial_tx_interrupt(struct serial_p
*/
while ( !spin_trylock(&port->tx_lock) )
{
- if ( !port->driver->tx_empty(port) )
+ if ( !port->driver->tx_ready(port) )
goto out;
cpu_relax();
}
- if ( port->driver->tx_empty(port) )
+ for ( i = 0, n = port->driver->tx_ready(port); i < n; i++ )
{
- for ( i = 0; i < port->tx_fifo_size; i++ )
- {
- if ( port->txbufc == port->txbufp )
- break;
- port->driver->putc(
- port,
port->txbuf[mask_serial_txbuf_idx(port->txbufc++)]);
- }
- if ( i && port->driver->flush )
- port->driver->flush(port);
+ if ( port->txbufc == port->txbufp )
+ break;
+ port->driver->putc(
+ port, port->txbuf[mask_serial_txbuf_idx(port->txbufc++)]);
}
+ if ( i && port->driver->flush )
+ port->driver->flush(port);
spin_unlock(&port->tx_lock);
@@ -114,10 +111,11 @@ static void __serial_putc(struct serial_
if ( port->tx_log_everything )
{
/* Buffer is full: we spin waiting for space to appear. */
- int i;
- while ( !port->driver->tx_empty(port) )
+ unsigned int n;
+
+ while ( (n = port->driver->tx_ready(port)) == 0 )
cpu_relax();
- for ( i = 0; i < port->tx_fifo_size; i++ )
+ while ( n-- )
port->driver->putc(
port,
port->txbuf[mask_serial_txbuf_idx(port->txbufc++)]);
@@ -132,7 +130,7 @@ static void __serial_putc(struct serial_
}
if ( ((port->txbufp - port->txbufc) == 0) &&
- port->driver->tx_empty(port) )
+ port->driver->tx_ready(port) )
{
/* Buffer and UART FIFO are both empty. */
port->driver->putc(port, c);
@@ -143,10 +141,10 @@ static void __serial_putc(struct serial_
port->txbuf[mask_serial_txbuf_idx(port->txbufp++)] = c;
}
}
- else if ( port->driver->tx_empty )
+ else if ( port->driver->tx_ready )
{
/* Synchronous finite-capacity transmitter. */
- while ( !port->driver->tx_empty(port) )
+ while ( !port->driver->tx_ready(port) )
cpu_relax();
port->driver->putc(port, c);
}
@@ -386,7 +384,7 @@ void serial_start_sync(int handle)
{
while ( (port->txbufp - port->txbufc) != 0 )
{
- while ( !port->driver->tx_empty(port) )
+ while ( !port->driver->tx_ready(port) )
cpu_relax();
port->driver->putc(
port,
port->txbuf[mask_serial_txbuf_idx(port->txbufc++)]);
@@ -506,14 +504,11 @@ void __init serial_register_uart(int idx
/* Store UART-specific info. */
com[idx].driver = driver;
com[idx].uart = uart;
-
- /* Default is no transmit FIFO. */
- com[idx].tx_fifo_size = 1;
}
void __init serial_async_transmit(struct serial_port *port)
{
- BUG_ON(!port->driver->tx_empty);
+ BUG_ON(!port->driver->tx_ready);
if ( port->txbuf != NULL )
return;
if ( serial_txbufsz < PAGE_SIZE )
--- a/xen/include/xen/serial.h
+++ b/xen/include/xen/serial.h
@@ -36,8 +36,6 @@ struct serial_port {
struct uart_driver *driver;
void *uart;
enum serial_port_state state;
- /* Number of characters the port can hold for transmit. */
- int tx_fifo_size;
/* Transmit data buffer (interrupt-driven uart). */
char *txbuf;
unsigned int txbufp, txbufc;
@@ -63,8 +61,8 @@ struct uart_driver {
/* Driver suspend/resume. */
void (*suspend)(struct serial_port *);
void (*resume)(struct serial_port *);
- /* Transmit FIFO ready to receive up to @tx_fifo_size characters? */
- int (*tx_empty)(struct serial_port *);
+ /* Return number of characters the port can hold for transmit. */
+ unsigned int (*tx_ready)(struct serial_port *);
/* Put a character onto the serial line. */
void (*putc)(struct serial_port *, char);
/* Flush accumulated characters. */
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