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path: root/drivers/serial/amba-pl011.c
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Diffstat (limited to 'drivers/serial/amba-pl011.c')
-rw-r--r--drivers/serial/amba-pl011.c90
1 files changed, 76 insertions, 14 deletions
diff --git a/drivers/serial/amba-pl011.c b/drivers/serial/amba-pl011.c
index eb4cb480b93e..6ca7a44f29c2 100644
--- a/drivers/serial/amba-pl011.c
+++ b/drivers/serial/amba-pl011.c
@@ -69,9 +69,12 @@
struct uart_amba_port {
struct uart_port port;
struct clk *clk;
- unsigned int im; /* interrupt mask */
+ unsigned int im; /* interrupt mask */
unsigned int old_status;
- unsigned int ifls; /* vendor-specific */
+ unsigned int ifls; /* vendor-specific */
+ unsigned int lcrh_tx; /* vendor-specific */
+ unsigned int lcrh_rx; /* vendor-specific */
+ bool oversampling; /* vendor-specific */
bool autorts;
};
@@ -79,16 +82,25 @@ struct uart_amba_port {
struct vendor_data {
unsigned int ifls;
unsigned int fifosize;
+ unsigned int lcrh_tx;
+ unsigned int lcrh_rx;
+ bool oversampling;
};
static struct vendor_data vendor_arm = {
.ifls = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
.fifosize = 16,
+ .lcrh_tx = UART011_LCRH,
+ .lcrh_rx = UART011_LCRH,
+ .oversampling = false,
};
static struct vendor_data vendor_st = {
.ifls = UART011_IFLS_RX_HALF|UART011_IFLS_TX_HALF,
.fifosize = 64,
+ .lcrh_tx = ST_UART011_LCRH_TX,
+ .lcrh_rx = ST_UART011_LCRH_RX,
+ .oversampling = true,
};
static void pl011_stop_tx(struct uart_port *port)
@@ -327,12 +339,12 @@ static void pl011_break_ctl(struct uart_port *port, int break_state)
unsigned int lcr_h;
spin_lock_irqsave(&uap->port.lock, flags);
- lcr_h = readw(uap->port.membase + UART011_LCRH);
+ lcr_h = readw(uap->port.membase + uap->lcrh_tx);
if (break_state == -1)
lcr_h |= UART01x_LCRH_BRK;
else
lcr_h &= ~UART01x_LCRH_BRK;
- writew(lcr_h, uap->port.membase + UART011_LCRH);
+ writew(lcr_h, uap->port.membase + uap->lcrh_tx);
spin_unlock_irqrestore(&uap->port.lock, flags);
}
@@ -393,7 +405,17 @@ static int pl011_startup(struct uart_port *port)
writew(cr, uap->port.membase + UART011_CR);
writew(0, uap->port.membase + UART011_FBRD);
writew(1, uap->port.membase + UART011_IBRD);
- writew(0, uap->port.membase + UART011_LCRH);
+ writew(0, uap->port.membase + uap->lcrh_rx);
+ if (uap->lcrh_tx != uap->lcrh_rx) {
+ int i;
+ /*
+ * Wait 10 PCLKs before writing LCRH_TX register,
+ * to get this delay write read only register 10 times
+ */
+ for (i = 0; i < 10; ++i)
+ writew(0xff, uap->port.membase + UART011_MIS);
+ writew(0, uap->port.membase + uap->lcrh_tx);
+ }
writew(0, uap->port.membase + UART01x_DR);
while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY)
barrier();
@@ -422,10 +444,19 @@ static int pl011_startup(struct uart_port *port)
return retval;
}
+static void pl011_shutdown_channel(struct uart_amba_port *uap,
+ unsigned int lcrh)
+{
+ unsigned long val;
+
+ val = readw(uap->port.membase + lcrh);
+ val &= ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN);
+ writew(val, uap->port.membase + lcrh);
+}
+
static void pl011_shutdown(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
- unsigned long val;
/*
* disable all interrupts
@@ -450,9 +481,9 @@ static void pl011_shutdown(struct uart_port *port)
/*
* disable break condition and fifos
*/
- val = readw(uap->port.membase + UART011_LCRH);
- val &= ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN);
- writew(val, uap->port.membase + UART011_LCRH);
+ pl011_shutdown_channel(uap, uap->lcrh_rx);
+ if (uap->lcrh_rx != uap->lcrh_tx)
+ pl011_shutdown_channel(uap, uap->lcrh_tx);
/*
* Shut down the clock producer
@@ -472,8 +503,13 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios,
/*
* Ask the core to calculate the divisor for us.
*/
- baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
- quot = port->uartclk * 4 / baud;
+ baud = uart_get_baud_rate(port, termios, old, 0,
+ port->uartclk/(uap->oversampling ? 8 : 16));
+
+ if (baud > port->uartclk/16)
+ quot = DIV_ROUND_CLOSEST(port->uartclk * 8, baud);
+ else
+ quot = DIV_ROUND_CLOSEST(port->uartclk * 4, baud);
switch (termios->c_cflag & CSIZE) {
case CS5:
@@ -552,6 +588,13 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios,
uap->autorts = false;
}
+ if (uap->oversampling) {
+ if (baud > port->uartclk/16)
+ old_cr |= ST_UART011_CR_OVSFACT;
+ else
+ old_cr &= ~ST_UART011_CR_OVSFACT;
+ }
+
/* Set baud rate */
writew(quot & 0x3f, port->membase + UART011_FBRD);
writew(quot >> 6, port->membase + UART011_IBRD);
@@ -561,7 +604,17 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios,
* NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
* ----------^----------^----------^----------^-----
*/
- writew(lcr_h, port->membase + UART011_LCRH);
+ writew(lcr_h, port->membase + uap->lcrh_rx);
+ if (uap->lcrh_rx != uap->lcrh_tx) {
+ int i;
+ /*
+ * Wait 10 PCLKs before writing LCRH_TX register,
+ * to get this delay write read only register 10 times
+ */
+ for (i = 0; i < 10; ++i)
+ writew(0xff, uap->port.membase + UART011_MIS);
+ writew(lcr_h, port->membase + uap->lcrh_tx);
+ }
writew(old_cr, port->membase + UART011_CR);
spin_unlock_irqrestore(&port->lock, flags);
@@ -688,7 +741,7 @@ pl011_console_get_options(struct uart_amba_port *uap, int *baud,
if (readw(uap->port.membase + UART011_CR) & UART01x_CR_UARTEN) {
unsigned int lcr_h, ibrd, fbrd;
- lcr_h = readw(uap->port.membase + UART011_LCRH);
+ lcr_h = readw(uap->port.membase + uap->lcrh_tx);
*parity = 'n';
if (lcr_h & UART01x_LCRH_PEN) {
@@ -707,6 +760,12 @@ pl011_console_get_options(struct uart_amba_port *uap, int *baud,
fbrd = readw(uap->port.membase + UART011_FBRD);
*baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd);
+
+ if (uap->oversampling) {
+ if (readw(uap->port.membase + UART011_CR)
+ & ST_UART011_CR_OVSFACT)
+ *baud *= 2;
+ }
}
}
@@ -800,6 +859,9 @@ static int pl011_probe(struct amba_device *dev, struct amba_id *id)
}
uap->ifls = vendor->ifls;
+ uap->lcrh_rx = vendor->lcrh_rx;
+ uap->lcrh_tx = vendor->lcrh_tx;
+ uap->oversampling = vendor->oversampling;
uap->port.dev = &dev->dev;
uap->port.mapbase = dev->res.start;
uap->port.membase = base;
@@ -868,7 +930,7 @@ static int pl011_resume(struct amba_device *dev)
}
#endif
-static struct amba_id pl011_ids[] __initdata = {
+static struct amba_id pl011_ids[] = {
{
.id = 0x00041011,
.mask = 0x000fffff,
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.