linux-kernel - [PATCH V5] scsi: ufs: core: store min and max clk freq from OPP table

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Date:   Fri,  8 Dec 2023 18:43:31 +0530
From:   Nitin Rawat <quic_nitirawa@...cinc.com>
To:     "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Manivannan Sadhasivam <mani@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc:     linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
        quic_cang@...cinc.com, Nitin Rawat <quic_nitirawa@...cinc.com>,
        Manish Pandey <quic_mapa@...cinc.com>
Subject: [PATCH V5] scsi: ufs: core: store min and max clk freq from OPP table

OPP support added by commit 72208ebe181e ("scsi: ufs: core: Add support
for parsing OPP") doesn't update the min_freq and max_freq of each clocks
in 'struct ufs_clk_info'.

But these values are used by the host drivers internally for controller
configuration. When the OPP support is enabled in devicetree, these
values will be 0, causing boot issues on the respective platforms.

So add support to parse the min_freq and max_freq of all clocks while
parsing the OPP table.

Fixes: 72208ebe181e ("scsi: ufs: core: Add support for parsing OPP")
Co-developed-by: Manish Pandey <quic_mapa@...cinc.com>
Signed-off-by: Manish Pandey <quic_mapa@...cinc.com>
Signed-off-by: Nitin Rawat <quic_nitirawa@...cinc.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
---
Change from v4:
- Addressed bart's comment to simplify the code

Changes from v3:
- updated commit description and comment to address christoph's comment

Changes from v2:
- increment idx in dev_pm_opp_get_freq_indexed

Changes from v1:
As per Manivannan's comment:
- Updated commmit description
- Sort include file alphabetically
- Added missing dev_pm_opp_put
- updated function name and documention
- removed ret variable
---
 drivers/ufs/host/ufshcd-pltfrm.c | 54 ++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/drivers/ufs/host/ufshcd-pltfrm.c b/drivers/ufs/host/ufshcd-pltfrm.c
index da2558e274b4..db9d9365ff55 100644
--- a/drivers/ufs/host/ufshcd-pltfrm.c
+++ b/drivers/ufs/host/ufshcd-pltfrm.c
@@ -8,6 +8,7 @@
  *	Vinayak Holikatti <h.vinayak@...sung.com>
  */

+#include <linux/clk.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/pm_opp.h>
@@ -213,6 +214,55 @@ static void ufshcd_init_lanes_per_dir(struct ufs_hba *hba)
 	}
 }

+/**
+ * ufshcd_parse_clock_min_max_freq  - Parse MIN and MAX clocks freq
+ * @hba: per adapter instance
+ *
+ * This function parses MIN and MAX frequencies of all clocks required
+ * by the host drivers.
+ *
+ * Returns 0 for success and non-zero for failure
+ */
+static int ufshcd_parse_clock_min_max_freq(struct ufs_hba *hba)
+{
+	struct list_head *head = &hba->clk_list_head;
+	struct ufs_clk_info *clki;
+	struct dev_pm_opp *opp;
+	unsigned long freq;
+	u8 idx = 0;
+
+	list_for_each_entry(clki, head, list) {
+		if (!clki->name)
+			continue;
+
+		clki->clk = devm_clk_get(hba->dev, clki->name);
+		if (IS_ERR(clki->clk))
+			continue;
+
+		/* Find Max Freq */
+		freq = ULONG_MAX;
+		opp = dev_pm_opp_find_freq_floor_indexed(hba->dev, &freq, idx);
+		if (IS_ERR(opp)) {
+			dev_err(hba->dev, "Failed to find OPP for MAX frequency\n");
+			return PTR_ERR(opp);
+		}
+		clki->max_freq = dev_pm_opp_get_freq_indexed(opp, idx);
+		dev_pm_opp_put(opp);
+
+		/* Find Min Freq */
+		freq = 0;
+		opp = dev_pm_opp_find_freq_ceil_indexed(hba->dev, &freq, idx);
+		if (IS_ERR(opp)) {
+			dev_err(hba->dev, "Failed to find OPP for MIN frequency\n");
+			return PTR_ERR(opp);
+		}
+		clki->min_freq = dev_pm_opp_get_freq_indexed(opp, idx++);
+		dev_pm_opp_put(opp);
+	}
+
+	return 0;
+}
+
 static int ufshcd_parse_operating_points(struct ufs_hba *hba)
 {
 	struct device *dev = hba->dev;
@@ -279,6 +329,10 @@ static int ufshcd_parse_operating_points(struct ufs_hba *hba)
 		return ret;
 	}

+	ret = ufshcd_parse_clock_min_max_freq(hba);
+	if (ret)
+		return ret;
+
 	hba->use_pm_opp = true;

 	return 0;
--
2.17.1