[<PATCH v1> 1/1] scsi: qcom-ufs: Add support for bus voting using ICB framework

[<PATCH v1> 1/1] scsi: qcom-ufs: Add support for bus voting using ICB framework

[Asutosh Das]

Adapt to the new ICB framework for bus bandwidth voting.

This requires the source/destination port ids.
Also this requires a tuple of values.

The tuple is for two different paths - from UFS master
to BIMC slave. The other is from CPU master to UFS slave.
This tuple consists of the average and peak bandwidth.

Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
---
 .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      |  12 ++
 drivers/scsi/ufs/ufs-qcom.c                        | 234 ++++++++++++++++-----
 drivers/scsi/ufs/ufs-qcom.h                        |  20 ++
 3 files changed, 218 insertions(+), 48 deletions(-)

diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
index a99ed55..94249ef 100644
--- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
+++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
@@ -45,6 +45,18 @@ Optional properties:
 Note: If above properties are not defined it can be assumed that the supply
 regulators or clocks are always on.
 
+* Following bus parameters are required:
+interconnects
+interconnect-names
+- Please refer to Documentation/devicetree/bindings/interconnect/
+  for more details on the above.
+qcom,msm-bus,name - string describing the bus path
+qcom,msm-bus,num-cases - number of configurations in which ufs can operate in
+qcom,msm-bus,num-paths - number of paths to vote for
+qcom,msm-bus,vectors-KBps - Takes a tuple <ib ab>, <ib ab> (2 tuples for 2 num-paths)
+			    The number of these entries *must* be same as
+			    num-cases.
+
 Example:
 	ufshc@0xfc598000 {
 		compatible = "jedec,ufs-1.1";
diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
index 2b38db2..213e975 100644
--- a/drivers/scsi/ufs/ufs-qcom.c
+++ b/drivers/scsi/ufs/ufs-qcom.c
@@ -16,6 +16,7 @@
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/phy/phy.h>
+#include <linux/interconnect.h>
 #include <linux/phy/phy-qcom-ufs.h>
 
 #include "ufshcd.h"
@@ -27,6 +28,10 @@
 #define UFS_QCOM_DEFAULT_DBG_PRINT_EN	\
 	(UFS_QCOM_DBG_PRINT_REGS_EN | UFS_QCOM_DBG_PRINT_TEST_BUS_EN)
 
+#define UFS_DDR "ufs-ddr"
+#define CPU_UFS "cpu-ufs"
+
+
 enum {
 	TSTBUS_UAWM,
 	TSTBUS_UARM,
@@ -714,7 +719,6 @@ static int ufs_qcom_get_pwr_dev_param(struct ufs_qcom_dev_params *qcom_param,
 	return 0;
 }
 
-#ifdef CONFIG_MSM_BUS_SCALING
 static int ufs_qcom_get_bus_vote(struct ufs_qcom_host *host,
 		const char *speed_mode)
 {
@@ -768,24 +772,83 @@ static void ufs_qcom_get_speed_mode(struct ufs_pa_layer_attr *p, char *result)
 	}
 }
 
+static int ufs_qcom_get_ib_ab(struct ufs_qcom_host *host, int index,
+			      struct qcom_bus_vectors *ufs_ddr_vec,
+			      struct qcom_bus_vectors *cpu_ufs_vec)
+{
+	struct qcom_bus_path *usecase;
+
+	if (!host->qbsd)
+		return -EINVAL;
+
+	if (index > host->qbsd->num_usecase)
+		return -EINVAL;
+
+	usecase = host->qbsd->usecase;
+
+	/*
+	 *
+	 * usecase:0  usecase:0
+	 * ufs->ddr   cpu->ufs
+	 * |vec[0&1] | vec[2&3]|
+	 * +----+----+----+----+
+	 * | ab | ib | ab | ib |
+	 * |----+----+----+----+
+	 * .
+	 * .
+	 * .
+	 * usecase:n  usecase:n
+	 * ufs->ddr   cpu->ufs
+	 * |vec[0&1] | vec[2&3]|
+	 * +----+----+----+----+
+	 * | ab | ib | ab | ib |
+	 * |----+----+----+----+
+	 */
+
+	/* index refers to offset in usecase */
+	ufs_ddr_vec->ab = usecase[index].vec[0].ab;
+	ufs_ddr_vec->ib = usecase[index].vec[0].ib;
+
+	cpu_ufs_vec->ab = usecase[index].vec[1].ab;
+	cpu_ufs_vec->ib = usecase[index].vec[1].ib;
+
+	return 0;
+}
+
 static int ufs_qcom_set_bus_vote(struct ufs_qcom_host *host, int vote)
 {
 	int err = 0;
+	struct qcom_bus_scale_data *d = host->qbsd;
+	struct qcom_bus_vectors path0, path1;
+	struct device *dev = host->hba->dev;
 
-	if (vote != host->bus_vote.curr_vote) {
-		err = msm_bus_scale_client_update_request(
-				host->bus_vote.client_handle, vote);
-		if (err) {
-			dev_err(host->hba->dev,
-				"%s: msm_bus_scale_client_update_request() failed: bus_client_handle=0x%x, vote=%d, err=%d\n",
-				__func__, host->bus_vote.client_handle,
-				vote, err);
-			goto out;
-		}
+	err = ufs_qcom_get_ib_ab(host, vote, &path0, &path1);
+	if (err) {
+		dev_err(dev, "Error: failed (%d) to get ib/ab\n",
+			err);
+		return err;
+	}
 
-		host->bus_vote.curr_vote = vote;
+	dev_dbg(dev, "Setting vote: %d: ufs-ddr: ab: %llu ib: %llu\n", vote,
+		path0.ab, path0.ib);
+	err = icc_set_bw(d->ufs_ddr, path0.ab, path0.ib);
+	if (err) {
+		dev_err(dev, "Error: (%d) failed setting (%s) bus vote\n", err,
+			UFS_DDR);
+		return err;
 	}
-out:
+
+	dev_dbg(dev, "Setting: cpu-ufs: ab: %llu ib: %llu\n", path1.ab,
+		path1.ib);
+	err = icc_set(d->cpu_ufs, path1.ab, path1.ib);
+	if (err) {
+		dev_err(dev, "Error: (%d) failed setting (%s) bus vote\n", err,
+			CPU_UFS);
+		return err;
+	}
+
+	host->bus_vote.curr_vote = vote;
+
 	return err;
 }
 
@@ -807,6 +870,7 @@ static int ufs_qcom_update_bus_bw_vote(struct ufs_qcom_host *host)
 		dev_err(host->hba->dev, "%s: failed %d\n", __func__, err);
 	else
 		host->bus_vote.saved_vote = vote;
+
 	return err;
 }
 
@@ -837,34 +901,114 @@ static int ufs_qcom_update_bus_bw_vote(struct ufs_qcom_host *host)
 	return count;
 }
 
+static struct qcom_bus_scale_data *ufs_qcom_get_bus_scale_data(struct device
+							       *dev)
+
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct device_node *of_node = dev->of_node;
+	struct qcom_bus_scale_data *qsd;
+	struct qcom_bus_path *usecase = NULL;
+	int ret = 0, i = 0, j, num_paths, len;
+	const uint32_t *vec_arr = NULL;
+	bool mem_err = false;
+
+	if (!pdev) {
+		dev_err(dev, "Null platform device!\n");
+		return NULL;
+	}
+
+	qsd = devm_kzalloc(dev, sizeof(struct qcom_bus_scale_data), GFP_KERNEL);
+	if (!qsd)
+		return NULL;
+
+	ret = of_property_read_string(of_node, "qcom,msm-bus,name", &qsd->name);
+	if (ret) {
+		dev_err(dev, "Error: (%d) Bus name missing!\n", ret);
+		return NULL;
+	}
+
+	ret = of_property_read_u32(of_node, "qcom,msm-bus,num-cases",
+		&qsd->num_usecase);
+	if (ret) {
+		pr_err("Error: num-usecases not found\n");
+		goto err;
+	}
+
+	usecase = devm_kzalloc(dev, (sizeof(struct qcom_bus_path) *
+				   qsd->num_usecase), GFP_KERNEL);
+	if (!usecase)
+		return NULL;
+
+	ret = of_property_read_u32(of_node, "qcom,msm-bus,num-paths",
+				   &num_paths);
+	if (ret) {
+		pr_err("Error: num_paths not found\n");
+		return NULL;
+	}
+
+	vec_arr = of_get_property(of_node, "qcom,msm-bus,vectors-KBps", &len);
+	if (vec_arr == NULL) {
+		pr_err("Error: Vector array not found\n");
+		return NULL;
+	}
+
+	for (i = 0; i < qsd->num_usecase; i++) {
+		usecase[i].num_paths = num_paths;
+		usecase[i].vec = devm_kzalloc(dev, num_paths *
+					      sizeof(struct qcom_bus_vectors),
+					      GFP_KERNEL);
+		if (!usecase[i].vec) {
+			mem_err = true;
+			dev_err(dev, "Error: Failed to alloc mem for vectors\n");
+			goto err;
+		}
+
+		for (j = 0; j < num_paths; j++) {
+			int idx = ((i * num_paths) + j) * 2;
+
+			usecase[i].vec[j].ab = (uint64_t)
+				be32_to_cpu(vec_arr[idx]);
+			usecase[i].vec[j].ib = (uint64_t)
+				be32_to_cpu(vec_arr[idx + 1]);
+		}
+	}
+
+	qsd->usecase = usecase;
+	return qsd;
+err:
+	if (mem_err) {
+		for (; i > 0; i--)
+			kfree(usecase[i].vec);
+	}
+	return NULL;
+}
+
 static int ufs_qcom_bus_register(struct ufs_qcom_host *host)
 {
 	int err;
-	struct msm_bus_scale_pdata *bus_pdata;
 	struct device *dev = host->hba->dev;
-	struct platform_device *pdev = to_platform_device(dev);
-	struct device_node *np = dev->of_node;
+	struct qcom_bus_scale_data *qsd;
 
-	bus_pdata = msm_bus_cl_get_pdata(pdev);
-	if (!bus_pdata) {
-		dev_err(dev, "%s: failed to get bus vectors\n", __func__);
-		err = -ENODATA;
-		goto out;
+	qsd = ufs_qcom_get_bus_scale_data(dev);
+	if (!qsd) {
+		dev_err(dev, "Failed: getting bus_scale data\n");
+		return 0;
 	}
+	host->qbsd = qsd;
 
-	err = of_property_count_strings(np, "qcom,bus-vector-names");
-	if (err < 0 || err != bus_pdata->num_usecases) {
-		dev_err(dev, "%s: qcom,bus-vector-names not specified correctly %d\n",
-				__func__, err);
-		goto out;
+	qsd->ufs_ddr = of_icc_get(dev, UFS_DDR);
+	if (IS_ERR(qsd->ufs_ddr)) {
+		dev_err(dev, "Error: (%d) failed getting %s path\n",
+			PTR_ERR(qsd->ufs_ddr), UFS_DDR);
+		return PTR_ERR(qsd->ufs_ddr);
 	}
 
-	host->bus_vote.client_handle = msm_bus_scale_register_client(bus_pdata);
-	if (!host->bus_vote.client_handle) {
-		dev_err(dev, "%s: msm_bus_scale_register_client failed\n",
-				__func__);
-		err = -EFAULT;
-		goto out;
+	qsd->cpu_ufs = of_icc_get(dev, CPU_UFS);
+	if (IS_ERR(qsd->cpu_ufs)) {
+		dev_err(dev, "Error: (%d) failed getting %s path\n",
+			PTR_ERR(qsd->cpu_ufs), CPU_UFS);
+		return PTR_ERR(qsd->cpu_ufs);
 	}
 
 	/* cache the vote index for minimum and maximum bandwidth */
@@ -877,25 +1021,19 @@ static int ufs_qcom_bus_register(struct ufs_qcom_host *host)
 	host->bus_vote.max_bus_bw.attr.name = "max_bus_bw";
 	host->bus_vote.max_bus_bw.attr.mode = S_IRUGO | S_IWUSR;
 	err = device_create_file(dev, &host->bus_vote.max_bus_bw);
-out:
-	return err;
-}
-#else /* CONFIG_MSM_BUS_SCALING */
-static int ufs_qcom_update_bus_bw_vote(struct ufs_qcom_host *host)
-{
-	return 0;
-}
+	if (err)
+		dev_err(dev, "Error: (%d) Failed to create sysfs entries\n",
+			err);
 
-static int ufs_qcom_set_bus_vote(struct ufs_qcom_host *host, int vote)
-{
-	return 0;
-}
+	/* Full throttle */
+	err = ufs_qcom_set_bus_vote(host, host->bus_vote.max_bw_vote);
+	if (err)
+		dev_err(dev, "Error: (%d) Failed to set max bus vote\n", err);
 
-static int ufs_qcom_bus_register(struct ufs_qcom_host *host)
-{
-	return 0;
+	dev_info(dev, "-- (%s) Registered bus voting! (%d) --\n", err);
+
+	return err;
 }
-#endif /* CONFIG_MSM_BUS_SCALING */
 
 static void ufs_qcom_dev_ref_clk_ctrl(struct ufs_qcom_host *host, bool enable)
 {
diff --git a/drivers/scsi/ufs/ufs-qcom.h b/drivers/scsi/ufs/ufs-qcom.h
index 295f4be..02140bd 100644
--- a/drivers/scsi/ufs/ufs-qcom.h
+++ b/drivers/scsi/ufs/ufs-qcom.h
@@ -207,6 +207,25 @@ struct ufs_qcom_testbus {
 	u8 select_minor;
 };
 
+struct qcom_bus_vectors {
+	uint64_t ab;
+	uint64_t ib;
+};
+
+struct qcom_bus_path {
+	unsigned int num_paths;
+	struct qcom_bus_vectors *vec;
+};
+
+struct qcom_bus_scale_data {
+	struct qcom_bus_path *usecase;
+	unsigned int num_usecase;
+	struct icc_path *ufs_ddr;
+	struct icc_path *cpu_ufs;
+
+	const char *name;
+};
+
 struct ufs_qcom_host {
 	/*
 	 * Set this capability if host controller supports the QUniPro mode
@@ -242,6 +261,7 @@ struct ufs_qcom_host {
 	/* Bitmask for enabling debug prints */
 	u32 dbg_print_en;
 	struct ufs_qcom_testbus testbus;
+	struct qcom_bus_scale_data *qbsd;
 };
 
 static inline u32
-- 
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [<PATCH v1> 1/1] scsi: qcom-ufs: Add support for bus voting using ICB framework

[Georgi Djakov]

Hi Asutosh,

Thanks for the patch!

On 1/24/19 09:01, Asutosh Das wrote:
> Adapt to the new ICB framework for bus bandwidth voting.

It's actually called interconnect API or interconnect framework.

> This requires the source/destination port ids.
> Also this requires a tuple of values.
> 
> The tuple is for two different paths - from UFS master
> to BIMC slave. The other is from CPU master to UFS slave.
> This tuple consists of the average and peak bandwidth.
> 
> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
> ---

You can put here (below the --- line) the text from the cover letter.
Usually people do not add separate cover letters for single patches.

>  .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      |  12 ++
>  drivers/scsi/ufs/ufs-qcom.c                        | 234 ++++++++++++++++-----
>  drivers/scsi/ufs/ufs-qcom.h                        |  20 ++
>  3 files changed, 218 insertions(+), 48 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> index a99ed55..94249ef 100644
> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> @@ -45,6 +45,18 @@ Optional properties:
>  Note: If above properties are not defined it can be assumed that the supply
>  regulators or clocks are always on.
>  
> +* Following bus parameters are required:
> +interconnects
> +interconnect-names

Is the above really required? Are the interconnect bandwidth requests
required to enable something critical to UFS functionality?
Would UFS still work without any bandwidth scaling, although for example
slower? Could you please clarify.

> +- Please refer to Documentation/devicetree/bindings/interconnect/
> +  for more details on the above.
> +qcom,msm-bus,name - string describing the bus path
> +qcom,msm-bus,num-cases - number of configurations in which ufs can operate in
> +qcom,msm-bus,num-paths - number of paths to vote for
> +qcom,msm-bus,vectors-KBps - Takes a tuple <ib ab>, <ib ab> (2 tuples for 2 num-paths)
> +			    The number of these entries *must* be same as
> +			    num-cases.

DT bindings should be submitted as a separate patch. Anyway, people
frown upon putting configuration data in DT. Could we put this data into
the driver as a static table instead of DT? Also maybe use ab/pb for
average/peak bandwidth.

> +
>  Example:
>  	ufshc@0xfc598000 {
>  		compatible = "jedec,ufs-1.1";
> diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
> index 2b38db2..213e975 100644
> --- a/drivers/scsi/ufs/ufs-qcom.c
> +++ b/drivers/scsi/ufs/ufs-qcom.c
> @@ -16,6 +16,7 @@
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
>  #include <linux/phy/phy.h>
> +#include <linux/interconnect.h>
>  #include <linux/phy/phy-qcom-ufs.h>

Alphabetical order?

>  
>  #include "ufshcd.h"
> @@ -27,6 +28,10 @@
>  #define UFS_QCOM_DEFAULT_DBG_PRINT_EN	\
>  	(UFS_QCOM_DBG_PRINT_REGS_EN | UFS_QCOM_DBG_PRINT_TEST_BUS_EN)
>  
> +#define UFS_DDR "ufs-ddr"
> +#define CPU_UFS "cpu-ufs"

Not sure if it's really useful to have them as #defines. Also maybe use
"ufs-mem" instead of "ufs-ddr" to be more consistent with other users.

> +
> +
>  enum {
>  	TSTBUS_UAWM,
>  	TSTBUS_UARM,
> @@ -714,7 +719,6 @@ static int ufs_qcom_get_pwr_dev_param(struct ufs_qcom_dev_params *qcom_param,
>  	return 0;
>  }
>  
> -#ifdef CONFIG_MSM_BUS_SCALING
>  static int ufs_qcom_get_bus_vote(struct ufs_qcom_host *host,
>  		const char *speed_mode)
>  {
> @@ -768,24 +772,83 @@ static void ufs_qcom_get_speed_mode(struct ufs_pa_layer_attr *p, char *result)
>  	}
>  }
>  
> +static int ufs_qcom_get_ib_ab(struct ufs_qcom_host *host, int index,
> +			      struct qcom_bus_vectors *ufs_ddr_vec,
> +			      struct qcom_bus_vectors *cpu_ufs_vec)
> +{
> +	struct qcom_bus_path *usecase;
> +
> +	if (!host->qbsd)
> +		return -EINVAL;
> +
> +	if (index > host->qbsd->num_usecase)
> +		return -EINVAL;
> +
> +	usecase = host->qbsd->usecase;
> +
> +	/*
> +	 *
> +	 * usecase:0  usecase:0
> +	 * ufs->ddr   cpu->ufs
> +	 * |vec[0&1] | vec[2&3]|
> +	 * +----+----+----+----+
> +	 * | ab | ib | ab | ib |
> +	 * |----+----+----+----+
> +	 * .
> +	 * .
> +	 * .
> +	 * usecase:n  usecase:n
> +	 * ufs->ddr   cpu->ufs
> +	 * |vec[0&1] | vec[2&3]|
> +	 * +----+----+----+----+
> +	 * | ab | ib | ab | ib |
> +	 * |----+----+----+----+
> +	 */
> +
> +	/* index refers to offset in usecase */
> +	ufs_ddr_vec->ab = usecase[index].vec[0].ab;
> +	ufs_ddr_vec->ib = usecase[index].vec[0].ib;
> +
> +	cpu_ufs_vec->ab = usecase[index].vec[1].ab;
> +	cpu_ufs_vec->ib = usecase[index].vec[1].ib;
> +
> +	return 0;
> +}
> +
>  static int ufs_qcom_set_bus_vote(struct ufs_qcom_host *host, int vote)
>  {
>  	int err = 0;
> +	struct qcom_bus_scale_data *d = host->qbsd;
> +	struct qcom_bus_vectors path0, path1;
> +	struct device *dev = host->hba->dev;
>  
> -	if (vote != host->bus_vote.curr_vote) {
> -		err = msm_bus_scale_client_update_request(
> -				host->bus_vote.client_handle, vote);
> -		if (err) {
> -			dev_err(host->hba->dev,
> -				"%s: msm_bus_scale_client_update_request() failed: bus_client_handle=0x%x, vote=%d, err=%d\n",
> -				__func__, host->bus_vote.client_handle,
> -				vote, err);
> -			goto out;
> -		}
> +	err = ufs_qcom_get_ib_ab(host, vote, &path0, &path1);
> +	if (err) {
> +		dev_err(dev, "Error: failed (%d) to get ib/ab\n",
> +			err);
> +		return err;
> +	}
>  
> -		host->bus_vote.curr_vote = vote;
> +	dev_dbg(dev, "Setting vote: %d: ufs-ddr: ab: %llu ib: %llu\n", vote,
> +		path0.ab, path0.ib);
> +	err = icc_set_bw(d->ufs_ddr, path0.ab, path0.ib);
> +	if (err) {
> +		dev_err(dev, "Error: (%d) failed setting (%s) bus vote\n", err,
> +			UFS_DDR);
> +		return err;
>  	}
> -out:
> +
> +	dev_dbg(dev, "Setting: cpu-ufs: ab: %llu ib: %llu\n", path1.ab,
> +		path1.ib);
> +	err = icc_set(d->cpu_ufs, path1.ab, path1.ib);
> +	if (err) {
> +		dev_err(dev, "Error: (%d) failed setting (%s) bus vote\n", err,
> +			CPU_UFS);
> +		return err;
> +	}
> +
> +	host->bus_vote.curr_vote = vote;
> +
>  	return err;
>  }
>  
> @@ -807,6 +870,7 @@ static int ufs_qcom_update_bus_bw_vote(struct ufs_qcom_host *host)
>  		dev_err(host->hba->dev, "%s: failed %d\n", __func__, err);
>  	else
>  		host->bus_vote.saved_vote = vote;
> +
>  	return err;
>  }
>  
> @@ -837,34 +901,114 @@ static int ufs_qcom_update_bus_bw_vote(struct ufs_qcom_host *host)
>  	return count;
>  }
>  
> +static struct qcom_bus_scale_data *ufs_qcom_get_bus_scale_data(struct device
> +							       *dev)
> +
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct device_node *of_node = dev->of_node;
> +	struct qcom_bus_scale_data *qsd;
> +	struct qcom_bus_path *usecase = NULL;
> +	int ret = 0, i = 0, j, num_paths, len;
> +	const uint32_t *vec_arr = NULL;

Please use u32 instead of uint32_t.

> +	bool mem_err = false;
> +
> +	if (!pdev) {
> +		dev_err(dev, "Null platform device!\n");
> +		return NULL;
> +	}
> +
> +	qsd = devm_kzalloc(dev, sizeof(struct qcom_bus_scale_data), GFP_KERNEL);
> +	if (!qsd)
> +		return NULL;
> +
> +	ret = of_property_read_string(of_node, "qcom,msm-bus,name", &qsd->name);
> +	if (ret) {
> +		dev_err(dev, "Error: (%d) Bus name missing!\n", ret);
> +		return NULL;
> +	}
> +
> +	ret = of_property_read_u32(of_node, "qcom,msm-bus,num-cases",
> +		&qsd->num_usecase);
> +	if (ret) {
> +		pr_err("Error: num-usecases not found\n");
> +		goto err;
> +	}
> +
> +	usecase = devm_kzalloc(dev, (sizeof(struct qcom_bus_path) *
> +				   qsd->num_usecase), GFP_KERNEL);
> +	if (!usecase)
> +		return NULL;
> +
> +	ret = of_property_read_u32(of_node, "qcom,msm-bus,num-paths",
> +				   &num_paths);
> +	if (ret) {
> +		pr_err("Error: num_paths not found\n");
> +		return NULL;
> +	}
> +
> +	vec_arr = of_get_property(of_node, "qcom,msm-bus,vectors-KBps", &len);
> +	if (vec_arr == NULL) {
> +		pr_err("Error: Vector array not found\n");
> +		return NULL;
> +	}
> +
> +	for (i = 0; i < qsd->num_usecase; i++) {
> +		usecase[i].num_paths = num_paths;
> +		usecase[i].vec = devm_kzalloc(dev, num_paths *
> +					      sizeof(struct qcom_bus_vectors),
> +					      GFP_KERNEL);
> +		if (!usecase[i].vec) {
> +			mem_err = true;
> +			dev_err(dev, "Error: Failed to alloc mem for vectors\n");
> +			goto err;
> +		}
> +
> +		for (j = 0; j < num_paths; j++) {
> +			int idx = ((i * num_paths) + j) * 2;
> +
> +			usecase[i].vec[j].ab = (uint64_t)
> +				be32_to_cpu(vec_arr[idx]);
> +			usecase[i].vec[j].ib = (uint64_t)
> +				be32_to_cpu(vec_arr[idx + 1]);
> +		}
> +	}
> +
> +	qsd->usecase = usecase;
> +	return qsd;
> +err:
> +	if (mem_err) {
> +		for (; i > 0; i--)
> +			kfree(usecase[i].vec);
> +	}
> +	return NULL;
> +}

We wouldn't need all the above DT parsing if we add a sdm845 bandwidth
usecase table. Could you give it a try?

Thanks,
Georgi

Re: [<PATCH v1> 1/1] scsi: qcom-ufs: Add support for bus voting using ICB framework

[Asutosh Das (asd)]

On 1/24/2019 5:16 PM, Georgi Djakov wrote:
> Hi Asutosh,
> 
> Thanks for the patch!
> 
> On 1/24/19 09:01, Asutosh Das wrote:
>> Adapt to the new ICB framework for bus bandwidth voting.
> 
> It's actually called interconnect API or interconnect framework.
Thanks! will change it.
> 
>> This requires the source/destination port ids.
>> Also this requires a tuple of values.
>>
>> The tuple is for two different paths - from UFS master
>> to BIMC slave. The other is from CPU master to UFS slave.
>> This tuple consists of the average and peak bandwidth.
>>
>> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
>> ---
> 
> You can put here (below the --- line) the text from the cover letter.
> Usually people do not add separate cover letters for single patches.

Ok - will do so.
> 
>>   .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      |  12 ++
>>   drivers/scsi/ufs/ufs-qcom.c                        | 234 ++++++++++++++++-----
>>   drivers/scsi/ufs/ufs-qcom.h                        |  20 ++
>>   3 files changed, 218 insertions(+), 48 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>> index a99ed55..94249ef 100644
>> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>> @@ -45,6 +45,18 @@ Optional properties:
>>   Note: If above properties are not defined it can be assumed that the supply
>>   regulators or clocks are always on.
>>   
>> +* Following bus parameters are required:
>> +interconnects
>> +interconnect-names
> 
> Is the above really required? Are the interconnect bandwidth requests
> required to enable something critical to UFS functionality?
> Would UFS still work without any bandwidth scaling, although for example
> slower? Could you please clarify.
Yes - UFS will still work without any bandwidth scaling - but the 
performance would be terrible.

> 
>> +- Please refer to Documentation/devicetree/bindings/interconnect/
>> +  for more details on the above.
>> +qcom,msm-bus,name - string describing the bus path
>> +qcom,msm-bus,num-cases - number of configurations in which ufs can operate in
>> +qcom,msm-bus,num-paths - number of paths to vote for
>> +qcom,msm-bus,vectors-KBps - Takes a tuple <ib ab>, <ib ab> (2 tuples for 2 num-paths)
>> +			    The number of these entries *must* be same as
>> +			    num-cases.
> 
> DT bindings should be submitted as a separate patch. Anyway, people
> frown upon putting configuration data in DT. Could we put this data into
> the driver as a static table instead of DT? Also maybe use ab/pb for
> average/peak bandwidth.
The ab/ib value change depending on the target - that's the reasoning 
for putting it in dts file. However, I'm open to ideas as to how else to 
handle this.

Agree to changing it to pb.

> 
>> +
>>   Example:
>>   	ufshc@0xfc598000 {
>>   		compatible = "jedec,ufs-1.1";
>> diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
>> index 2b38db2..213e975 100644
>> --- a/drivers/scsi/ufs/ufs-qcom.c
>> +++ b/drivers/scsi/ufs/ufs-qcom.c
>> @@ -16,6 +16,7 @@
>>   #include <linux/of.h>
>>   #include <linux/platform_device.h>
>>   #include <linux/phy/phy.h>
>> +#include <linux/interconnect.h>
>>   #include <linux/phy/phy-qcom-ufs.h>
> 
> Alphabetical order?
Agreed.

> 
>>   
>>   #include "ufshcd.h"
>> @@ -27,6 +28,10 @@
>>   #define UFS_QCOM_DEFAULT_DBG_PRINT_EN	\
>>   	(UFS_QCOM_DBG_PRINT_REGS_EN | UFS_QCOM_DBG_PRINT_TEST_BUS_EN)
>>   
>> +#define UFS_DDR "ufs-ddr"
>> +#define CPU_UFS "cpu-ufs"
> 
> Not sure if it's really useful to have them as #defines. Also maybe use
> "ufs-mem" instead of "ufs-ddr" to be more consistent with other users.
I can declare these as strings too - I don't have a preference.
Please let me know if you've a preference.
The reason for ufs-ddr was that it describes the path from ufs device to 
ddr. Am fine with ufs-mem too.

> 
>> +
>> +
>>   enum {
>>   	TSTBUS_UAWM,
>>   	TSTBUS_UARM,
>> @@ -714,7 +719,6 @@ static int ufs_qcom_get_pwr_dev_param(struct ufs_qcom_dev_params *qcom_param,
>>   	return 0;
>>   }
>>   
>> -#ifdef CONFIG_MSM_BUS_SCALING
>>   static int ufs_qcom_get_bus_vote(struct ufs_qcom_host *host,
>>   		const char *speed_mode)
>>   {
>> @@ -768,24 +772,83 @@ static void ufs_qcom_get_speed_mode(struct ufs_pa_layer_attr *p, char *result)
>>   	}
>>   }
>>   
>> +static int ufs_qcom_get_ib_ab(struct ufs_qcom_host *host, int index,
>> +			      struct qcom_bus_vectors *ufs_ddr_vec,
>> +			      struct qcom_bus_vectors *cpu_ufs_vec)
>> +{
>> +	struct qcom_bus_path *usecase;
>> +
>> +	if (!host->qbsd)
>> +		return -EINVAL;
>> +
>> +	if (index > host->qbsd->num_usecase)
>> +		return -EINVAL;
>> +
>> +	usecase = host->qbsd->usecase;
>> +
>> +	/*
>> +	 *
>> +	 * usecase:0  usecase:0
>> +	 * ufs->ddr   cpu->ufs
>> +	 * |vec[0&1] | vec[2&3]|
>> +	 * +----+----+----+----+
>> +	 * | ab | ib | ab | ib |
>> +	 * |----+----+----+----+
>> +	 * .
>> +	 * .
>> +	 * .
>> +	 * usecase:n  usecase:n
>> +	 * ufs->ddr   cpu->ufs
>> +	 * |vec[0&1] | vec[2&3]|
>> +	 * +----+----+----+----+
>> +	 * | ab | ib | ab | ib |
>> +	 * |----+----+----+----+
>> +	 */
>> +
>> +	/* index refers to offset in usecase */
>> +	ufs_ddr_vec->ab = usecase[index].vec[0].ab;
>> +	ufs_ddr_vec->ib = usecase[index].vec[0].ib;
>> +
>> +	cpu_ufs_vec->ab = usecase[index].vec[1].ab;
>> +	cpu_ufs_vec->ib = usecase[index].vec[1].ib;
>> +
>> +	return 0;
>> +}
>> +
>>   static int ufs_qcom_set_bus_vote(struct ufs_qcom_host *host, int vote)
>>   {
>>   	int err = 0;
>> +	struct qcom_bus_scale_data *d = host->qbsd;
>> +	struct qcom_bus_vectors path0, path1;
>> +	struct device *dev = host->hba->dev;
>>   
>> -	if (vote != host->bus_vote.curr_vote) {
>> -		err = msm_bus_scale_client_update_request(
>> -				host->bus_vote.client_handle, vote);
>> -		if (err) {
>> -			dev_err(host->hba->dev,
>> -				"%s: msm_bus_scale_client_update_request() failed: bus_client_handle=0x%x, vote=%d, err=%d\n",
>> -				__func__, host->bus_vote.client_handle,
>> -				vote, err);
>> -			goto out;
>> -		}
>> +	err = ufs_qcom_get_ib_ab(host, vote, &path0, &path1);
>> +	if (err) {
>> +		dev_err(dev, "Error: failed (%d) to get ib/ab\n",
>> +			err);
>> +		return err;
>> +	}
>>   
>> -		host->bus_vote.curr_vote = vote;
>> +	dev_dbg(dev, "Setting vote: %d: ufs-ddr: ab: %llu ib: %llu\n", vote,
>> +		path0.ab, path0.ib);
>> +	err = icc_set_bw(d->ufs_ddr, path0.ab, path0.ib);
>> +	if (err) {
>> +		dev_err(dev, "Error: (%d) failed setting (%s) bus vote\n", err,
>> +			UFS_DDR);
>> +		return err;
>>   	}
>> -out:
>> +
>> +	dev_dbg(dev, "Setting: cpu-ufs: ab: %llu ib: %llu\n", path1.ab,
>> +		path1.ib);
>> +	err = icc_set(d->cpu_ufs, path1.ab, path1.ib);
>> +	if (err) {
>> +		dev_err(dev, "Error: (%d) failed setting (%s) bus vote\n", err,
>> +			CPU_UFS);
>> +		return err;
>> +	}
>> +
>> +	host->bus_vote.curr_vote = vote;
>> +
>>   	return err;
>>   }
>>   
>> @@ -807,6 +870,7 @@ static int ufs_qcom_update_bus_bw_vote(struct ufs_qcom_host *host)
>>   		dev_err(host->hba->dev, "%s: failed %d\n", __func__, err);
>>   	else
>>   		host->bus_vote.saved_vote = vote;
>> +
>>   	return err;
>>   }
>>   
>> @@ -837,34 +901,114 @@ static int ufs_qcom_update_bus_bw_vote(struct ufs_qcom_host *host)
>>   	return count;
>>   }
>>   
>> +static struct qcom_bus_scale_data *ufs_qcom_get_bus_scale_data(struct device
>> +							       *dev)
>> +
>> +{
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	struct device_node *of_node = dev->of_node;
>> +	struct qcom_bus_scale_data *qsd;
>> +	struct qcom_bus_path *usecase = NULL;
>> +	int ret = 0, i = 0, j, num_paths, len;
>> +	const uint32_t *vec_arr = NULL;
> 
> Please use u32 instead of uint32_t.
Agreed.

> 
>> +	bool mem_err = false;
>> +
>> +	if (!pdev) {
>> +		dev_err(dev, "Null platform device!\n");
>> +		return NULL;
>> +	}
>> +
>> +	qsd = devm_kzalloc(dev, sizeof(struct qcom_bus_scale_data), GFP_KERNEL);
>> +	if (!qsd)
>> +		return NULL;
>> +
>> +	ret = of_property_read_string(of_node, "qcom,msm-bus,name", &qsd->name);
>> +	if (ret) {
>> +		dev_err(dev, "Error: (%d) Bus name missing!\n", ret);
>> +		return NULL;
>> +	}
>> +
>> +	ret = of_property_read_u32(of_node, "qcom,msm-bus,num-cases",
>> +		&qsd->num_usecase);
>> +	if (ret) {
>> +		pr_err("Error: num-usecases not found\n");
>> +		goto err;
>> +	}
>> +
>> +	usecase = devm_kzalloc(dev, (sizeof(struct qcom_bus_path) *
>> +				   qsd->num_usecase), GFP_KERNEL);
>> +	if (!usecase)
>> +		return NULL;
>> +
>> +	ret = of_property_read_u32(of_node, "qcom,msm-bus,num-paths",
>> +				   &num_paths);
>> +	if (ret) {
>> +		pr_err("Error: num_paths not found\n");
>> +		return NULL;
>> +	}
>> +
>> +	vec_arr = of_get_property(of_node, "qcom,msm-bus,vectors-KBps", &len);
>> +	if (vec_arr == NULL) {
>> +		pr_err("Error: Vector array not found\n");
>> +		return NULL;
>> +	}
>> +
>> +	for (i = 0; i < qsd->num_usecase; i++) {
>> +		usecase[i].num_paths = num_paths;
>> +		usecase[i].vec = devm_kzalloc(dev, num_paths *
>> +					      sizeof(struct qcom_bus_vectors),
>> +					      GFP_KERNEL);
>> +		if (!usecase[i].vec) {
>> +			mem_err = true;
>> +			dev_err(dev, "Error: Failed to alloc mem for vectors\n");
>> +			goto err;
>> +		}
>> +
>> +		for (j = 0; j < num_paths; j++) {
>> +			int idx = ((i * num_paths) + j) * 2;
>> +
>> +			usecase[i].vec[j].ab = (uint64_t)
>> +				be32_to_cpu(vec_arr[idx]);
>> +			usecase[i].vec[j].ib = (uint64_t)
>> +				be32_to_cpu(vec_arr[idx + 1]);
>> +		}
>> +	}
>> +
>> +	qsd->usecase = usecase;
>> +	return qsd;
>> +err:
>> +	if (mem_err) {
>> +		for (; i > 0; i--)
>> +			kfree(usecase[i].vec);
>> +	}
>> +	return NULL;
>> +}
> 
> We wouldn't need all the above DT parsing if we add a sdm845 bandwidth
> usecase table. Could you give it a try?
Replied above - Please let me know if you've any suggestions on how else 
to handle this, as it can change with targets.

> 
> Thanks,
> Georgi
> 

Hi Georgi - thanks for the comments.
Replied to your comments inline.

-asd

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a 
Linux Foundation Collaborative Project

Re: [<PATCH v1> 1/1] scsi: qcom-ufs: Add support for bus voting using ICB framework

[Georgi Djakov]

Hi Asutosh,

On 1/25/19 12:27, Asutosh Das (asd) wrote:
> On 1/24/2019 5:16 PM, Georgi Djakov wrote:
[..]>>> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>>> b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>>> index a99ed55..94249ef 100644
>>> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>>> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>>> @@ -45,6 +45,18 @@ Optional properties:
>>>   Note: If above properties are not defined it can be assumed that
>>> the supply
>>>   regulators or clocks are always on.
>>>   +* Following bus parameters are required:
>>> +interconnects
>>> +interconnect-names
>>
>> Is the above really required? Are the interconnect bandwidth requests
>> required to enable something critical to UFS functionality?
>> Would UFS still work without any bandwidth scaling, although for example
>> slower? Could you please clarify.
> Yes - UFS will still work without any bandwidth scaling - but the
> performance would be terrible.

Ok, thanks for clarifying! Then the properties should be optional. Maybe
we can also mention in the commit text how much the performance would
improve with this patch.

>>
>>> +- Please refer to Documentation/devicetree/bindings/interconnect/
>>> +  for more details on the above.
>>> +qcom,msm-bus,name - string describing the bus path
>>> +qcom,msm-bus,num-cases - number of configurations in which ufs can
>>> operate in
>>> +qcom,msm-bus,num-paths - number of paths to vote for
>>> +qcom,msm-bus,vectors-KBps - Takes a tuple <ib ab>, <ib ab> (2 tuples
>>> for 2 num-paths)
>>> +                The number of these entries *must* be same as
>>> +                num-cases.
>>
>> DT bindings should be submitted as a separate patch. Anyway, people
>> frown upon putting configuration data in DT. Could we put this data into
>> the driver as a static table instead of DT? Also maybe use ab/pb for
>> average/peak bandwidth.
> The ab/ib value change depending on the target - that's the reasoning
> for putting it in dts file. However, I'm open to ideas as to how else to
> handle this.

As Evan already suggested, it would be best if we can calculate the
bandwidth. Can we do that based on the number of lanes, clock rate and
ufs standard version?
If calculating is really not possible and we have strong arguments for
that, we could add a more specific compatible DT string - for example
qcom,sdm845-ufshc and use per SoC bandwidth tables.

Thanks,
Georgi

Re: [<PATCH v1> 1/1] scsi: qcom-ufs: Add support for bus voting using ICB framework

[Evan Green]

On Wed, Jan 23, 2019 at 11:02 PM Asutosh Das <asutoshd@codeaurora.org> wrote:
>
> Adapt to the new ICB framework for bus bandwidth voting.
>
> This requires the source/destination port ids.
> Also this requires a tuple of values.
>
> The tuple is for two different paths - from UFS master
> to BIMC slave. The other is from CPU master to UFS slave.
> This tuple consists of the average and peak bandwidth.
>
> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
> ---
>  .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      |  12 ++
>  drivers/scsi/ufs/ufs-qcom.c                        | 234 ++++++++++++++++-----
>  drivers/scsi/ufs/ufs-qcom.h                        |  20 ++
>  3 files changed, 218 insertions(+), 48 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> index a99ed55..94249ef 100644
> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> @@ -45,6 +45,18 @@ Optional properties:
>  Note: If above properties are not defined it can be assumed that the supply
>  regulators or clocks are always on.
>
> +* Following bus parameters are required:
> +interconnects
> +interconnect-names
> +- Please refer to Documentation/devicetree/bindings/interconnect/
> +  for more details on the above.
> +qcom,msm-bus,name - string describing the bus path
> +qcom,msm-bus,num-cases - number of configurations in which ufs can operate in
> +qcom,msm-bus,num-paths - number of paths to vote for
> +qcom,msm-bus,vectors-KBps - Takes a tuple <ib ab>, <ib ab> (2 tuples for 2 num-paths)
> +                           The number of these entries *must* be same as
> +                           num-cases.

I think we can do away with all of the qcom* ones, right? This should
be achievable with just interconnects and interconnect-names.

Also, is this patch based on a downstream tree? I don't recognize a
lot of the context. We'll need a patch that's based on an upstream
tree.

I'll wait to review the rest of the patch until rev 2, since it's hard
to reason about the patch with all the downstream stuff in there.
-Evan

Re: [<PATCH v1> 1/1] scsi: qcom-ufs: Add support for bus voting using ICB framework

[Asutosh Das (asd)]

On 1/24/2019 10:22 PM, Evan Green wrote:
> On Wed, Jan 23, 2019 at 11:02 PM Asutosh Das <asutoshd@codeaurora.org> wrote:
>>
>> Adapt to the new ICB framework for bus bandwidth voting.
>>
>> This requires the source/destination port ids.
>> Also this requires a tuple of values.
>>
>> The tuple is for two different paths - from UFS master
>> to BIMC slave. The other is from CPU master to UFS slave.
>> This tuple consists of the average and peak bandwidth.
>>
>> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
>> ---
>>   .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      |  12 ++
>>   drivers/scsi/ufs/ufs-qcom.c                        | 234 ++++++++++++++++-----
>>   drivers/scsi/ufs/ufs-qcom.h                        |  20 ++
>>   3 files changed, 218 insertions(+), 48 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>> index a99ed55..94249ef 100644
>> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>> @@ -45,6 +45,18 @@ Optional properties:
>>   Note: If above properties are not defined it can be assumed that the supply
>>   regulators or clocks are always on.
>>
>> +* Following bus parameters are required:
>> +interconnects
>> +interconnect-names
>> +- Please refer to Documentation/devicetree/bindings/interconnect/
>> +  for more details on the above.
>> +qcom,msm-bus,name - string describing the bus path
>> +qcom,msm-bus,num-cases - number of configurations in which ufs can operate in
>> +qcom,msm-bus,num-paths - number of paths to vote for
>> +qcom,msm-bus,vectors-KBps - Takes a tuple <ib ab>, <ib ab> (2 tuples for 2 num-paths)
>> +                           The number of these entries *must* be same as
>> +                           num-cases.
> 
> I think we can do away with all of the qcom* ones, right? This should
> be achievable with just interconnects and interconnect-names.
Let me give that a bit more thought - though I'm not sure how that'd work.

> 
> Also, is this patch based on a downstream tree? I don't recognize a
> lot of the context. We'll need a patch that's based on an upstream
> tree.
This was developed on the internal Chrome AU and ported to ufs-next.
Let me check internally on this anyway.

> 
> I'll wait to review the rest of the patch until rev 2, since it's hard
> to reason about the patch with all the downstream stuff in there.
> -Evan
> 

Hi Evan - thanks for the comments.

-asd

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Re: [<PATCH v1> 1/1] scsi: qcom-ufs: Add support for bus voting using ICB framework

[Evan Green]

On Fri, Jan 25, 2019 at 2:29 AM Asutosh Das (asd)
<asutoshd@codeaurora.org> wrote:
>
> On 1/24/2019 10:22 PM, Evan Green wrote:
> > On Wed, Jan 23, 2019 at 11:02 PM Asutosh Das <asutoshd@codeaurora.org> wrote:
> >>
> >> Adapt to the new ICB framework for bus bandwidth voting.
> >>
> >> This requires the source/destination port ids.
> >> Also this requires a tuple of values.
> >>
> >> The tuple is for two different paths - from UFS master
> >> to BIMC slave. The other is from CPU master to UFS slave.
> >> This tuple consists of the average and peak bandwidth.
> >>
> >> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
> >> ---
> >>   .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      |  12 ++
> >>   drivers/scsi/ufs/ufs-qcom.c                        | 234 ++++++++++++++++-----
> >>   drivers/scsi/ufs/ufs-qcom.h                        |  20 ++
> >>   3 files changed, 218 insertions(+), 48 deletions(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> >> index a99ed55..94249ef 100644
> >> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> >> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> >> @@ -45,6 +45,18 @@ Optional properties:
> >>   Note: If above properties are not defined it can be assumed that the supply
> >>   regulators or clocks are always on.
> >>
> >> +* Following bus parameters are required:
> >> +interconnects
> >> +interconnect-names
> >> +- Please refer to Documentation/devicetree/bindings/interconnect/
> >> +  for more details on the above.
> >> +qcom,msm-bus,name - string describing the bus path
> >> +qcom,msm-bus,num-cases - number of configurations in which ufs can operate in
> >> +qcom,msm-bus,num-paths - number of paths to vote for
> >> +qcom,msm-bus,vectors-KBps - Takes a tuple <ib ab>, <ib ab> (2 tuples for 2 num-paths)
> >> +                           The number of these entries *must* be same as
> >> +                           num-cases.
> >
> > I think we can do away with all of the qcom* ones, right? This should
> > be achievable with just interconnects and interconnect-names.
> Let me give that a bit more thought - though I'm not sure how that'd work.

>From the downstream kernel that I have, it looks like these are
basically used to define the bandwidth values for each gear/mode in
UFS. My understanding is that the DT folks generally balk at having
configuration data in the device tree. I'm hopeful that we can have a
snippet of code that actually computes the required bandwidth for a
certain combination of gear speed and lanes. But if that is somehow
not possible, this can at worst be a table in code of
bandwidths[gear]. But let's try for the computation first.

>
> >
> > Also, is this patch based on a downstream tree? I don't recognize a
> > lot of the context. We'll need a patch that's based on an upstream
> > tree.
> This was developed on the internal Chrome AU and ported to ufs-next.
> Let me check internally on this anyway.
>

Whoops, you're right, the context I was confused about does appear to
be upstream. I was unaware there was dangling code to the old
downstream bus scaling stuff in the upstream kernel. I think we should
get rid of all of that and start fresh.

Also, like the dangling downstream code was, the new stuff should
probably be surrounded by ifdefs for the new interconnect core.

I also think we don't really need the max_bus_bw thing, so when we rip
out all the downstream leftovers we don't need to put that back in.

-Evan