[PATCH V8 7/8] spi: spi-qcom-qspi: Add interconnect support

Akash Asthana
2020-06-23T10:40:19Z

Get the interconnect paths for QSPI device and vote according to the
current bus speed of the driver.

Signed-off-by: Akash Asthana <akashast@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
---
Changes in V2:
- 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:
- No Change.

Changes in V4:
- As per Mark's comment move peak_bw guess as twice of avg_bw if
nothing mentioned explicitly to ICC core.

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.

Changes in V6:
- As per Matthias's comment made print statement consistent across driver

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.
- As per Matthias's comment improved print log.

Changes in Resend V7:
- As per Matthias comment removed "unsigned int avg_bw_cpu" from
struct qcom_qspi as we are using that variable only once.

Changes in V8:
- No change

drivers/spi/spi-qcom-qspi.c | 56 ++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 55 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-qcom-qspi.c b/drivers/spi/spi-qcom-qspi.c
index 3c4f83b..b5b4cf6 100644
--- a/drivers/spi/spi-qcom-qspi.c
+++ b/drivers/spi/spi-qcom-qspi.c
@@ -2,6 +2,7 @@
// Copyright (c) 2017-2018, The Linux foundation. All rights reserved.

#include <linux/clk.h>
+#include <linux/interconnect.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
@@ -139,7 +140,8 @@ struct qcom_qspi {
struct device *dev;
struct clk_bulk_data *clks;
struct qspi_xfer xfer;
- /* Lock to protect xfer and IRQ accessed registers */
+ struct icc_path *icc_path_cpu_to_qspi;
+ /* Lock to protect data accessed by IRQs */
spinlock_t lock;
};

@@ -229,6 +231,7 @@ static int qcom_qspi_transfer_one(struct spi_master *master,
int ret;
unsigned long speed_hz;
unsigned long flags;
+ unsigned int avg_bw_cpu;

speed_hz = slv->max_speed_hz;
if (xfer->speed_hz)
@@ -241,6 +244,18 @@ static int qcom_qspi_transfer_one(struct spi_master *master,
return ret;
}

+ /*
+ * Set BW quota for CPU as driver supports FIFO mode only.
+ * We don't have explicit peak requirement so keep it equal to avg_bw.
+ */
+ avg_bw_cpu = Bps_to_icc(speed_hz);
+ ret = icc_set_bw(ctrl->icc_path_cpu_to_qspi, avg_bw_cpu, avg_bw_cpu);
+ if (ret) {
+ dev_err(ctrl->dev, "%s: ICC BW voting failed for cpu: %d\n",
+ __func__, ret);
+ return ret;
+ }
+
spin_lock_irqsave(&ctrl->lock, flags);

/* We are half duplex, so either rx or tx will be set */
@@ -458,6 +473,29 @@ static int qcom_qspi_probe(struct platform_device *pdev)
if (ret)
goto exit_probe_master_put;

+ ctrl->icc_path_cpu_to_qspi = devm_of_icc_get(dev, "qspi-config");
+ if (IS_ERR(ctrl->icc_path_cpu_to_qspi)) {
+ ret = PTR_ERR(ctrl->icc_path_cpu_to_qspi);
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "Failed to get cpu path: %d\n", ret);
+ goto exit_probe_master_put;
+ }
+ /* Set BW vote for register access */
+ ret = icc_set_bw(ctrl->icc_path_cpu_to_qspi, Bps_to_icc(1000),
+ Bps_to_icc(1000));
+ if (ret) {
+ dev_err(ctrl->dev, "%s: ICC BW voting failed for cpu: %d\n",
+ __func__, ret);
+ goto exit_probe_master_put;
+ }
+
+ ret = icc_disable(ctrl->icc_path_cpu_to_qspi);
+ if (ret) {
+ dev_err(ctrl->dev, "%s: ICC disable failed for cpu: %d\n",
+ __func__, ret);
+ goto exit_probe_master_put;
+ }
+
ret = platform_get_irq(pdev, 0);
if (ret < 0)
goto exit_probe_master_put;
@@ -511,9 +549,17 @@ static int __maybe_unused qcom_qspi_runtime_suspend(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct qcom_qspi *ctrl = spi_master_get_devdata(master);
+ int ret;

clk_bulk_disable_unprepare(QSPI_NUM_CLKS, ctrl->clks);

+ ret = icc_disable(ctrl->icc_path_cpu_to_qspi);
+ if (ret) {
+ dev_err_ratelimited(ctrl->dev, "%s: ICC disable failed for cpu: %d\n",
+ __func__, ret);
+ return ret;
+ }
+
return 0;
}

@@ -521,6 +567,14 @@ static int __maybe_unused qcom_qspi_runtime_resume(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct qcom_qspi *ctrl = spi_master_get_devdata(master);
+ int ret;
+
+ ret = icc_enable(ctrl->icc_path_cpu_to_qspi);
+ if (ret) {
+ dev_err_ratelimited(ctrl->dev, "%s: ICC enable failed for cpu: %d\n",
+ __func__, ret);
+ return ret;
+ }

return clk_bulk_prepare_enable(QSPI_NUM_CLKS, ctrl->clks);