[PATCH V8 6/8] spi: spi-geni-qcom: Add interconnect support

[Akash Asthana]

Get the interconnect paths for SPI based Serial Engine device
and vote according to the current bus speed of the driver.

Signed-off-by: Akash Asthana <akashast@xxxxxxxxxxxxxx>
---
Changes in V2:
 - As per Bjorn's comment, removed se == NULL check from geni_spi_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's comment, use helper ICC function from geni-se driver.

Changes in V4:
 - Move peak_bw guess as twice of avg_bw if nothing mentioned explicitly
   to ICC core.

Changes in V5:
 - Use icc_enable/disable in 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
   device will resume and suspend before probe return and will leave ICC in
   disabled state.

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:
 - Adjust ICC vote per transfer, in multimessage transfer scenario.
 - Move ICC voting to common API "geni_spi_set_clock_and_bw".

 drivers/spi/spi-geni-qcom.c | 36 ++++++++++++++++++++++++++++++++----
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
index f186906..7a2e579 100644
--- a/drivers/spi/spi-geni-qcom.c
+++ b/drivers/spi/spi-geni-qcom.c
@@ -192,7 +192,8 @@ static void spi_setup_word_len(struct spi_geni_master *mas, u16 mode,
 	writel(word_len, se->base + SE_SPI_WORD_LEN);
 }
 
-static int geni_spi_set_clock(struct spi_geni_master *mas, unsigned long clk_hz)
+static int geni_spi_set_clock_and_bw(struct spi_geni_master *mas,
+					unsigned long clk_hz)
 {
 	u32 clk_sel, m_clk_cfg, idx, div;
 	struct geni_se *se = &mas->se;
@@ -218,6 +219,12 @@ static int geni_spi_set_clock(struct spi_geni_master *mas, unsigned long clk_hz)
 	writel(clk_sel, se->base + SE_GENI_CLK_SEL);
 	writel(m_clk_cfg, se->base + GENI_SER_M_CLK_CFG);
 
+	/* Set BW quota for CPU as driver supports FIFO mode only. */
+	se->icc_paths[CPU_TO_GENI].avg_bw = Bps_to_icc(mas->cur_speed_hz);
+	ret = geni_icc_set_bw(se);
+	if (ret)
+		return ret;
+
 	return 0;
 }
 
@@ -259,7 +266,7 @@ static int setup_fifo_params(struct spi_device *spi_slv,
 	writel(cpol, se->base + SE_SPI_CPOL);
 	writel(demux_output_inv, se->base + SE_SPI_DEMUX_OUTPUT_INV);
 
-	return geni_spi_set_clock(mas, spi_slv->max_speed_hz);
+	return geni_spi_set_clock_and_bw(mas, spi_slv->max_speed_hz);
 }
 
 static int spi_geni_prepare_message(struct spi_master *spi,
@@ -346,7 +353,7 @@ static void setup_fifo_xfer(struct spi_transfer *xfer,
 
 	/* Speed and bits per word can be overridden per transfer */
 	if (xfer->speed_hz != mas->cur_speed_hz) {
-		ret = geni_spi_set_clock(mas, xfer->speed_hz);
+		ret = geni_spi_set_clock_and_bw(mas, xfer->speed_hz);
 		if (ret)
 			return;
 	}
@@ -620,6 +627,17 @@ static int spi_geni_probe(struct platform_device *pdev)
 	spin_lock_init(&mas->lock);
 	pm_runtime_enable(dev);
 
+	ret = geni_icc_get(&mas->se, NULL);
+	if (ret)
+		goto spi_geni_probe_runtime_disable;
+	/* Set the bus quota to a reasonable value for register access */
+	mas->se.icc_paths[GENI_TO_CORE].avg_bw = Bps_to_icc(CORE_2X_50_MHZ);
+	mas->se.icc_paths[CPU_TO_GENI].avg_bw = GENI_DEFAULT_BW;
+
+	ret = geni_icc_set_bw(&mas->se);
+	if (ret)
+		goto spi_geni_probe_runtime_disable;
+
 	ret = spi_geni_init(mas);
 	if (ret)
 		goto spi_geni_probe_runtime_disable;
@@ -658,14 +676,24 @@ static int __maybe_unused spi_geni_runtime_suspend(struct device *dev)
 {
 	struct spi_master *spi = dev_get_drvdata(dev);
 	struct spi_geni_master *mas = spi_master_get_devdata(spi);
+	int ret;
+
+	ret = geni_se_resources_off(&mas->se);
+	if (ret)
+		return ret;
 
-	return geni_se_resources_off(&mas->se);
+	return geni_icc_disable(&mas->se);
 }
 
 static int __maybe_unused spi_geni_runtime_resume(struct device *dev)
 {
 	struct spi_master *spi = dev_get_drvdata(dev);
 	struct spi_geni_master *mas = spi_master_get_devdata(spi);
+	int ret;
+
+	ret = geni_icc_enable(&mas->se);
+	if (ret)
+		return ret;
 
 	return geni_se_resources_on(&mas->se);
 }
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project