[PATCH v2 3/7] spi: qcom-qspi: Add interconnect support for memory path

[Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>]

The QSPI controller has two interconnect paths:
1. qspi-config: CPU to QSPI controller for register access
2. qspi-memory: QSPI controller to memory for DMA operations

Currently, the driver only manages the qspi-config path. Add support for
the qspi-memory path to ensure proper bandwidth allocation for QSPI data
transfers to/from memory. Enable and disable both paths during runtime PM
transitions.

Signed-off-by: Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>
---
 drivers/spi/spi-qcom-qspi.c | 41 +++++++++++++++++++++++++++++++++++------
 1 file changed, 35 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-qcom-qspi.c b/drivers/spi/spi-qcom-qspi.c
index 38af859713a7..c89d50d67dd2 100644
--- a/drivers/spi/spi-qcom-qspi.c
+++ b/drivers/spi/spi-qcom-qspi.c
@@ -174,6 +174,7 @@ struct qcom_qspi {
 	void *virt_cmd_desc[QSPI_MAX_SG];
 	unsigned int n_cmd_desc;
 	struct icc_path *icc_path_cpu_to_qspi;
+	struct icc_path *icc_path_mem;
 	unsigned long last_speed;
 	/* Lock to protect data accessed by IRQs */
 	spinlock_t lock;
@@ -272,7 +273,7 @@ static void qcom_qspi_handle_err(struct spi_controller *host,
 static int qcom_qspi_set_speed(struct qcom_qspi *ctrl, unsigned long speed_hz)
 {
 	int ret;
-	unsigned int avg_bw_cpu;
+	unsigned int avg_bw_cpu, avg_bw_mem;
 
 	if (speed_hz == ctrl->last_speed)
 		return 0;
@@ -285,7 +286,7 @@ static int qcom_qspi_set_speed(struct qcom_qspi *ctrl, unsigned long speed_hz)
 	}
 
 	/*
-	 * Set BW quota for CPU.
+	 * Set BW quota for CPU and memory paths.
 	 * We don't have explicit peak requirement so keep it equal to avg_bw.
 	 */
 	avg_bw_cpu = Bps_to_icc(speed_hz);
@@ -296,6 +297,13 @@ static int qcom_qspi_set_speed(struct qcom_qspi *ctrl, unsigned long speed_hz)
 		return ret;
 	}
 
+	avg_bw_mem = Bps_to_icc(speed_hz);
+	ret = icc_set_bw(ctrl->icc_path_mem, avg_bw_mem, avg_bw_mem);
+	if (ret) {
+		dev_err(ctrl->dev, "ICC BW voting failed for memory: %d\n", ret);
+		return ret;
+	}
+
 	ctrl->last_speed = speed_hz;
 
 	return 0;
@@ -729,6 +737,11 @@ static int qcom_qspi_probe(struct platform_device *pdev)
 		return dev_err_probe(dev, PTR_ERR(ctrl->icc_path_cpu_to_qspi),
 				     "Failed to get cpu path\n");
 
+	ctrl->icc_path_mem = devm_of_icc_get(dev, "qspi-memory");
+	if (IS_ERR(ctrl->icc_path_mem))
+		return dev_err_probe(dev, PTR_ERR(ctrl->icc_path_mem),
+				     "Failed to get memory path\n");
+
 	/* Set BW vote for register access */
 	ret = icc_set_bw(ctrl->icc_path_cpu_to_qspi, Bps_to_icc(1000),
 				Bps_to_icc(1000));
@@ -832,13 +845,21 @@ static int __maybe_unused qcom_qspi_runtime_suspend(struct device *dev)
 		goto err_enable_clk;
 	}
 
+	ret = icc_disable(ctrl->icc_path_mem);
+	if (ret) {
+		dev_err_ratelimited(ctrl->dev, "ICC disable failed for memory: %d\n", ret);
+		goto err_enable_icc_cpu;
+	}
+
 	ret = pinctrl_pm_select_sleep_state(dev);
 	if (ret)
-		goto err_enable_icc;
+		goto err_enable_icc_mem;
 
 	return 0;
 
-err_enable_icc:
+err_enable_icc_mem:
+	icc_enable(ctrl->icc_path_mem);
+err_enable_icc_cpu:
 	icc_enable(ctrl->icc_path_cpu_to_qspi);
 err_enable_clk:
 	clk_bulk_prepare_enable(QSPI_NUM_CLKS, ctrl->clks);
@@ -863,9 +884,15 @@ static int __maybe_unused qcom_qspi_runtime_resume(struct device *dev)
 		goto err_select_sleep_state;
 	}
 
+	ret = icc_enable(ctrl->icc_path_mem);
+	if (ret) {
+		dev_err_ratelimited(ctrl->dev, "ICC enable failed for memory: %d\n", ret);
+		goto err_disable_icc_cpu;
+	}
+
 	ret = clk_bulk_prepare_enable(QSPI_NUM_CLKS, ctrl->clks);
 	if (ret)
-		goto err_disable_icc;
+		goto err_disable_icc_mem;
 
 	ret = dev_pm_opp_set_rate(dev, ctrl->last_speed * 4);
 	if (ret)
@@ -875,7 +902,9 @@ static int __maybe_unused qcom_qspi_runtime_resume(struct device *dev)
 
 err_disable_clk:
 	clk_bulk_disable_unprepare(QSPI_NUM_CLKS, ctrl->clks);
-err_disable_icc:
+err_disable_icc_mem:
+	icc_disable(ctrl->icc_path_mem);
+err_disable_icc_cpu:
 	icc_disable(ctrl->icc_path_cpu_to_qspi);
 err_select_sleep_state:
 	pinctrl_pm_select_sleep_state(dev);

-- 
2.34.1