Replace the single sampling rate and special handling for HSCIF's
variable sampling rates by a bitmask and a custom iterator.
This prepares for the advent of SCIFA/SCIFB's sparse variable sampling
rates.
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
drivers/tty/serial/sh-sci.c | 66 +++++++++++++++++++--------------------------
1 file changed, 27 insertions(+), 39 deletions(-)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index f3c2a89a9550add9..17188fc4b1b32439 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -85,6 +85,18 @@ enum SCI_CLKS {
SCI_NUM_CLKS
};
+/* Bit x set means sampling rate x + 1 is supported */
+#define SCI_SR(x) BIT((x) - 1)
+#define SCI_SR_RANGE(x, y) GENMASK((y) - 1, (x) - 1)
+
+#define min_sr(_port) ffs((_port)->sampling_rate_mask)
+#define max_sr(_port) fls((_port)->sampling_rate_mask)
+
+/* Iterate over all supported sampling rates, from high to low */
+#define for_each_sr(_sr, _port) \
+ for ((_sr) = max_sr(_port); (_sr) >= min_sr(_port); (_sr)--) \
+ if ((_port)->sampling_rate_mask & SCI_SR((_sr)))
+
struct sci_port {
struct uart_port port;
@@ -94,7 +106,7 @@ struct sci_port {
unsigned int overrun_mask;
unsigned int error_mask;
unsigned int error_clear;
- unsigned int sampling_rate;
+ unsigned int sampling_rate_mask;
resource_size_t reg_size;
/* Break timer */
@@ -1931,21 +1943,13 @@ static int sci_sck_calc(struct sci_port *s, unsigned int bps,
unsigned int *srr)
{
unsigned long freq = s->clk_rates[SCI_SCK];
- unsigned int min_sr, max_sr, sr;
int err, min_err = INT_MAX;
+ unsigned int sr;
if (s->port.type != PORT_HSCIF)
freq *= 2;
- if (s->sampling_rate) {
- /* SCI(F) has a fixed sampling rate */
- min_sr = max_sr = s->sampling_rate;
- } else {
- /* HSCIF has a variable 1/(8..32) sampling rate */
- min_sr = 8;
- max_sr = 32;
- }
- for (sr = max_sr; sr >= min_sr; sr--) {
+ for_each_sr(sr, s) {
err = DIV_ROUND_CLOSEST(freq, sr) - bps;
if (abs(err) >= abs(min_err))
continue;
@@ -1966,21 +1970,13 @@ static int sci_brg_calc(struct sci_port *s, unsigned int bps,
unsigned long freq, unsigned int *dlr,
unsigned int *srr)
{
- unsigned int min_sr, max_sr, sr, dl;
int err, min_err = INT_MAX;
+ unsigned int sr, dl;
if (s->port.type != PORT_HSCIF)
freq *= 2;
- if (s->sampling_rate) {
- /* SCIF has a fixed sampling rate */
- min_sr = max_sr = s->sampling_rate;
- } else {
- /* HSCIF has a variable 1/(8..32) sampling rate */
- min_sr = 8;
- max_sr = 32;
- }
- for (sr = max_sr; sr >= min_sr; sr--) {
+ for_each_sr(sr, s) {
dl = DIV_ROUND_CLOSEST(freq, sr * bps);
dl = clamp(dl, 1U, 65535U);
@@ -2006,19 +2002,12 @@ static int sci_scbrr_calc(struct sci_port *s, unsigned int bps,
unsigned int *brr, unsigned int *srr,
unsigned int *cks)
{
- unsigned int min_sr, max_sr, sr, br, prediv, scrate, c;
unsigned long freq = s->clk_rates[SCI_FCK];
+ unsigned int sr, br, prediv, scrate, c;
int err, min_err = INT_MAX;
if (s->port.type != PORT_HSCIF)
freq *= 2;
- if (s->sampling_rate) {
- min_sr = max_sr = s->sampling_rate;
- } else {
- /* HSCIF has a variable sample rate */
- min_sr = 8;
- max_sr = 32;
- }
/*
* Find the combination of sample rate and clock select with the
@@ -2035,7 +2024,7 @@ static int sci_scbrr_calc(struct sci_port *s, unsigned int bps,
* (|D - 0.5| / N * (1 + F))|
* NOTE: Usually, treat D for 0.5, F is 0 by this calculation.
*/
- for (sr = max_sr; sr >= min_sr; sr--) {
+ for_each_sr(sr, s) {
for (c = 0; c <= 3; c++) {
/* integerized formulas from HSCIF documentation */
prediv = sr * (1 << (2 * c + 1));
@@ -2129,8 +2118,7 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
for (i = 0; i < SCI_NUM_CLKS; i++)
max_freq = max(max_freq, s->clk_rates[i]);
- baud = uart_get_baud_rate(port, termios, old, 0,
- max_freq / max(s->sampling_rate, 8U));
+ baud = uart_get_baud_rate(port, termios, old, 0, max_freq / min_sr(s));
if (!baud)
goto done;
@@ -2562,37 +2550,37 @@ static int sci_init_single(struct platform_device *dev,
port->fifosize = 256;
sci_port->overrun_reg = SCxSR;
sci_port->overrun_mask = SCIFA_ORER;
- sci_port->sampling_rate = 16;
+ sci_port->sampling_rate_mask = SCI_SR(16);
break;
case PORT_HSCIF:
port->fifosize = 128;
sci_port->overrun_reg = SCLSR;
sci_port->overrun_mask = SCLSR_ORER;
- sci_port->sampling_rate = 0;
+ sci_port->sampling_rate_mask = SCI_SR_RANGE(8, 32);
break;
case PORT_SCIFA:
port->fifosize = 64;
sci_port->overrun_reg = SCxSR;
sci_port->overrun_mask = SCIFA_ORER;
- sci_port->sampling_rate = 16;
+ sci_port->sampling_rate_mask = SCI_SR(16);
break;
case PORT_SCIF:
port->fifosize = 16;
if (p->regtype == SCIx_SH7705_SCIF_REGTYPE) {
sci_port->overrun_reg = SCxSR;
sci_port->overrun_mask = SCIFA_ORER;
- sci_port->sampling_rate = 16;
+ sci_port->sampling_rate_mask = SCI_SR(16);
} else {
sci_port->overrun_reg = SCLSR;
sci_port->overrun_mask = SCLSR_ORER;
- sci_port->sampling_rate = 32;
+ sci_port->sampling_rate_mask = SCI_SR(32);
}
break;
default:
port->fifosize = 1;
sci_port->overrun_reg = SCxSR;
sci_port->overrun_mask = SCI_ORER;
- sci_port->sampling_rate = 32;
+ sci_port->sampling_rate_mask = SCI_SR(32);
break;
}
@@ -2601,7 +2589,7 @@ static int sci_init_single(struct platform_device *dev,
* data override the sampling rate for now.
*/
if (p->sampling_rate)
- sci_port->sampling_rate = p->sampling_rate;
+ sci_port->sampling_rate_mask = SCI_SR(p->sampling_rate);
if (!early) {
ret = sci_init_clocks(sci_port, &dev->dev);
--
1.9.1
--
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