linux-kernel - [PATCH v7 1/1] dma: qcom: bam_dma: Add support to initialize interconnect path

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Message-Id: <20220921030649.1436434-2-bhupesh.sharma@linaro.org>
Date:   Wed, 21 Sep 2022 08:36:49 +0530
From:   Bhupesh Sharma <bhupesh.sharma@...aro.org>
To:     dmaengine@...r.kernel.org
Cc:     agross@...nel.org, linux-crypto@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        thara.gopinath@...il.com, devicetree@...r.kernel.org,
        andersson@...nel.org, bhupesh.sharma@...aro.org,
        bhupesh.linux@...il.com, vkoul@...nel.org,
        Rob Herring <robh@...nel.org>
Subject: [PATCH v7 1/1] dma: qcom: bam_dma: Add support to initialize interconnect path

From: Thara Gopinath <thara.gopinath@...il.com>

BAM dma engine associated with certain hardware blocks could require
relevant interconnect pieces be initialized prior to the dma engine
initialization. For e.g. crypto bam dma engine on sm8250. Such requirement
is passed on to the bam dma driver from dt via the "interconnects"
property. Add support in bam_dma driver to check whether the interconnect
path is accessible/enabled prior to attempting driver intializations.

If interconnects are not yet setup, defer the BAM DMA driver probe().

Cc: Bjorn Andersson <andersson@...nel.org>
Cc: Rob Herring <robh@...nel.org>
Signed-off-by: Thara Gopinath <thara.gopinath@...il.com>
Signed-off-by: Bhupesh Sharma <bhupesh.sharma@...aro.org>
[Bhupesh: Make header file inclusion alphabetical and use 'devm_of_icc_get()']
---
 drivers/dma/qcom/bam_dma.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index 2ff787df513e..a5b0cf28ffb7 100644
--- a/drivers/dma/qcom/bam_dma.c
+++ b/drivers/dma/qcom/bam_dma.c
@@ -26,6 +26,7 @@
 #include <linux/kernel.h>
 #include <linux/io.h>
 #include <linux/init.h>
+#include <linux/interconnect.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/interrupt.h>
@@ -394,6 +395,7 @@ struct bam_device {
 	const struct reg_offset_data *layout;
 
 	struct clk *bamclk;
+	struct icc_path *mem_path;
 	int irq;
 
 	/* dma start transaction tasklet */
@@ -1294,6 +1296,14 @@ static int bam_dma_probe(struct platform_device *pdev)
 	if (IS_ERR(bdev->bamclk))
 		return PTR_ERR(bdev->bamclk);
 
+	/* Ensure that interconnects are initialized */
+	bdev->mem_path = devm_of_icc_get(bdev->dev, "memory");
+	if (IS_ERR(bdev->mem_path)) {
+		ret = dev_err_probe(bdev->dev, PTR_ERR(bdev->mem_path),
+				    "failed to acquire icc path\n");
+		return ret;
+	}
+
 	ret = clk_prepare_enable(bdev->bamclk);
 	if (ret) {
 		dev_err(bdev->dev, "failed to prepare/enable clock\n");
-- 
2.37.1