[PATCH V8 4/8] tty: serial: qcom_geni_serial: Add interconnect support

Akash Asthana
2020-06-23T10:40:00Z

Get the interconnect paths for Uart based Serial Engine device
and vote according to the baud rate requirement of the driver.

Signed-off-by: Akash Asthana <akashast@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Changes in V2:
- As per Bjorn's comment, removed se == NULL check from geni_serial_icc_get
- As per Bjorn's comment, removed code to set se->icc_path* to NULL in failure
- As per Bjorn's comment, introduced and using devm_of_icc_get API for getting
path handle
- As per Matthias comment, added error handling for icc_set_bw call

Changes in V3:
- As per Matthias comment, use common library APIs defined in geni-se
driver for ICC functionality.

Changes in V4:
- As per Mark's comment move peak_bw guess as twice of avg_bw if
nothing mentioned explicitly to ICC core.
- As per Matthias's comment select core clock BW based on baud rate.
If it's less than 115200 go for GENI_DEFAULT_BW else CORE_2X_50_MHZ

Changes in V5:
- Add icc_enable/disable to power on/off call.
- Save some non-zero avg/peak value to ICC core by calling geni_icc_set_bw
from probe so that when resume/icc_enable is called NOC are running at
some non-zero value. No need to call icc_disable after BW vote because
console devices are expected to be in active state from the probe itself
and qcom_geni_serial_pm(STATE_OFF) will be called for non-console ones.

Changes in V6:
- No change

Changes in V7:
- As per Matthias's comment removed usage of peak_bw variable because we don't
have explicit peak requirement, we were voting peak = avg and this can be
tracked using single variable for avg bw.

Changes in V8:
- No change.

drivers/tty/serial/qcom_geni_serial.c | 31 ++++++++++++++++++++++++++++---
1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index a4468db..f701c7e 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -945,6 +945,7 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport,
struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
unsigned long clk_rate;
u32 ver, sampling_rate;
+ unsigned int avg_bw_core;

qcom_geni_serial_stop_rx(uport);
/* baud rate */
@@ -966,6 +967,16 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport,
ser_clk_cfg = SER_CLK_EN;
ser_clk_cfg |= clk_div << CLK_DIV_SHFT;

+ /*
+ * Bump up BW vote on CPU and CORE path as driver supports FIFO mode
+ * only.
+ */
+ avg_bw_core = (baud > 115200) ? Bps_to_icc(CORE_2X_50_MHZ)
+ : GENI_DEFAULT_BW;
+ port->se.icc_paths[GENI_TO_CORE].avg_bw = avg_bw_core;
+ port->se.icc_paths[CPU_TO_GENI].avg_bw = Bps_to_icc(baud);
+ geni_icc_set_bw(&port->se);
+
/* parity */
tx_trans_cfg = readl(uport->membase + SE_UART_TX_TRANS_CFG);
tx_parity_cfg = readl(uport->membase + SE_UART_TX_PARITY_CFG);
@@ -1235,11 +1246,14 @@ static void qcom_geni_serial_pm(struct uart_port *uport,
if (old_state == UART_PM_STATE_UNDEFINED)
old_state = UART_PM_STATE_OFF;

- if (new_state == UART_PM_STATE_ON && old_state == UART_PM_STATE_OFF)
+ if (new_state == UART_PM_STATE_ON && old_state == UART_PM_STATE_OFF) {
+ geni_icc_enable(&port->se);
geni_se_resources_on(&port->se);
- else if (new_state == UART_PM_STATE_OFF &&
- old_state == UART_PM_STATE_ON)
+ } else if (new_state == UART_PM_STATE_OFF &&
+ old_state == UART_PM_STATE_ON) {
geni_se_resources_off(&port->se);
+ geni_icc_disable(&port->se);
+ }
}

static const struct uart_ops qcom_geni_console_pops = {
@@ -1337,6 +1351,17 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
return -ENOMEM;
}

+ ret = geni_icc_get(&port->se, NULL);
+ if (ret)
+ return ret;
+ port->se.icc_paths[GENI_TO_CORE].avg_bw = GENI_DEFAULT_BW;
+ port->se.icc_paths[CPU_TO_GENI].avg_bw = GENI_DEFAULT_BW;
+
+ /* Set BW for register access */
+ ret = geni_icc_set_bw(&port->se);
+ if (ret)
+ return ret;
+
port->name = devm_kasprintf(uport->dev, GFP_KERNEL,
"qcom_geni_serial_%s%d",
uart_console(uport) ? "console" : "uart", uport->line);