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* [PATCH 0/2] bus: imx-weim
@ 2018-11-30 17:07 thesven73
  2018-11-30 17:07 ` [PATCH 1/2] bus: imx-weim: support multiple address ranges per child node thesven73
  2018-11-30 17:07 ` [PATCH 2/2] bus: imx-weim: guard against timing configuration conflicts thesven73
  0 siblings, 2 replies; 4+ messages in thread
From: thesven73 @ 2018-11-30 17:07 UTC (permalink / raw)
  To: TheSven73, Shawn Guo, Kees Cook, Rob Herring, Arnd Bergmann; +Cc: linux-kernel

From: Sven Van Asbroeck <TheSven73@googlemail.com>

Support multiple address ranges per child node on imx-weim.
While we're at it, insert some code which guards against common config
conflicts.

Sven Van Asbroeck (2):
  bus: imx-weim: support multiple address ranges per child node
  bus: imx-weim: guard against timing configuration conflicts

 drivers/bus/imx-weim.c | 69 +++++++++++++++++++++++++++++++++---------
 1 file changed, 55 insertions(+), 14 deletions(-)

-- 
2.17.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH 1/2] bus: imx-weim: support multiple address ranges per child node
  2018-11-30 17:07 [PATCH 0/2] bus: imx-weim thesven73
@ 2018-11-30 17:07 ` thesven73
  2018-11-30 17:07 ` [PATCH 2/2] bus: imx-weim: guard against timing configuration conflicts thesven73
  1 sibling, 0 replies; 4+ messages in thread
From: thesven73 @ 2018-11-30 17:07 UTC (permalink / raw)
  To: TheSven73, Shawn Guo, Kees Cook, Rob Herring, Arnd Bergmann; +Cc: linux-kernel

From: Sven Van Asbroeck <TheSven73@googlemail.com>

Ensure that timing values for the child node are applied to
all chip selects in the child's address ranges.

Note that this does not support multiple timing settings per
child; this can be added in the future if required.

Example:
&weim {
	acme@0 {
		compatible = "acme,whatever";
		reg = <0 0 0x100>, <0 0x400000 0x800>,
				<1 0x400000 0x800>;
		fsl,weim-cs-timing = <0x024400b1 0x00001010 0x20081100
				0x00000000 0xa0000240 0x00000000>;
	};
};

Signed-off-by: Sven Van Asbroeck <TheSven73@googlemail.com>
---
 drivers/bus/imx-weim.c | 36 +++++++++++++++++++++++++-----------
 1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c
index f01308172de9..24f22285395d 100644
--- a/drivers/bus/imx-weim.c
+++ b/drivers/bus/imx-weim.c
@@ -46,6 +46,7 @@ static const struct imx_weim_devtype imx51_weim_devtype = {
 };
 
 #define MAX_CS_REGS_COUNT	6
+#define OF_REG_SIZE		3
 
 static const struct of_device_id weim_id_table[] = {
 	/* i.MX1/21 */
@@ -115,27 +116,40 @@ static int __init weim_timing_setup(struct device_node *np, void __iomem *base,
 				    const struct imx_weim_devtype *devtype)
 {
 	u32 cs_idx, value[MAX_CS_REGS_COUNT];
-	int i, ret;
+	int i, ret, reg_idx, num_regs;
 
 	if (WARN_ON(devtype->cs_regs_count > MAX_CS_REGS_COUNT))
 		return -EINVAL;
 
-	/* get the CS index from this child node's "reg" property. */
-	ret = of_property_read_u32(np, "reg", &cs_idx);
+	ret = of_property_read_u32_array(np, "fsl,weim-cs-timing",
+					 value, devtype->cs_regs_count);
 	if (ret)
 		return ret;
 
-	if (cs_idx >= devtype->cs_count)
+	/*
+	 * the child node's "reg" property may contain multiple address ranges,
+	 * extract the chip select for each.
+	 */
+	num_regs = of_property_count_elems_of_size(np, "reg", OF_REG_SIZE);
+	if (num_regs < 0)
+		return num_regs;
+	if (!num_regs)
 		return -EINVAL;
+	for (reg_idx = 0; reg_idx < num_regs; reg_idx++) {
+		/* get the CS index from this child node's "reg" property. */
+		ret = of_property_read_u32_index(np, "reg",
+					reg_idx*OF_REG_SIZE, &cs_idx);
+		if (ret)
+			break;
 
-	ret = of_property_read_u32_array(np, "fsl,weim-cs-timing",
-					 value, devtype->cs_regs_count);
-	if (ret)
-		return ret;
+		if (cs_idx >= devtype->cs_count)
+			return -EINVAL;
 
-	/* set the timing for WEIM */
-	for (i = 0; i < devtype->cs_regs_count; i++)
-		writel(value[i], base + cs_idx * devtype->cs_stride + i * 4);
+		/* set the timing for WEIM */
+		for (i = 0; i < devtype->cs_regs_count; i++)
+			writel(value[i],
+				base + cs_idx * devtype->cs_stride + i * 4);
+	}
 
 	return 0;
 }
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* [PATCH 2/2] bus: imx-weim: guard against timing configuration conflicts
  2018-11-30 17:07 [PATCH 0/2] bus: imx-weim thesven73
  2018-11-30 17:07 ` [PATCH 1/2] bus: imx-weim: support multiple address ranges per child node thesven73
@ 2018-11-30 17:07 ` thesven73
  2018-11-30 19:59   ` Rob Herring
  1 sibling, 1 reply; 4+ messages in thread
From: thesven73 @ 2018-11-30 17:07 UTC (permalink / raw)
  To: TheSven73, Shawn Guo, Kees Cook, Rob Herring, Arnd Bergmann; +Cc: linux-kernel

From: Sven Van Asbroeck <TheSven73@googlemail.com>

When adding weim child devices, there is a risk that the developer will
(by mistake) specify more than one timing setting for the same chip select.

The driver cannot support such a configuration.

In case of conflict, this patch will print a warning to the log,
and will ignore the child node in question.

In this example, node acme@1 will be ignored, as it tries to modify
timing settings for CS0:

&weim {
	acme@0 {
		compatible = "acme,whatever";
		reg = <0 0 0x100>;
		fsl,weim-cs-timing = <something>;
	};
	acme@1 {
		compatible = "acme,whatnot";
		reg = <0 0x500 0x100>;
		fsl,weim-cs-timing = <something else>;
	};
};

However in this example, the driver will be happy:

&weim {
        acme@0 {
                compatible = "acme,whatever";
                reg = <0 0 0x100>;
                fsl,weim-cs-timing = <something>;
        };
        acme@1 {
                compatible = "acme,whatnot";
                reg = <0 0x500 0x100>;
                fsl,weim-cs-timing = <something>;
        };
};

Signed-off-by: Sven Van Asbroeck <TheSven73@googlemail.com>
---
 drivers/bus/imx-weim.c | 33 ++++++++++++++++++++++++++++++---
 1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c
index 24f22285395d..114e503ec785 100644
--- a/drivers/bus/imx-weim.c
+++ b/drivers/bus/imx-weim.c
@@ -46,8 +46,18 @@ static const struct imx_weim_devtype imx51_weim_devtype = {
 };
 
 #define MAX_CS_REGS_COUNT	6
+#define MAX_CS_REGS		6
 #define OF_REG_SIZE		3
 
+struct cs_timing {
+	bool is_applied;
+	u32 regs[MAX_CS_REGS_COUNT];
+};
+
+struct cs_timing_state {
+	struct cs_timing cs[MAX_CS_REGS];
+};
+
 static const struct of_device_id weim_id_table[] = {
 	/* i.MX1/21 */
 	{ .compatible = "fsl,imx1-weim", .data = &imx1_weim_devtype, },
@@ -112,11 +122,14 @@ static int __init imx_weim_gpr_setup(struct platform_device *pdev)
 }
 
 /* Parse and set the timing for this device. */
-static int __init weim_timing_setup(struct device_node *np, void __iomem *base,
-				    const struct imx_weim_devtype *devtype)
+static int __init weim_timing_setup(struct device *dev,
+				    struct device_node *np, void __iomem *base,
+				    const struct imx_weim_devtype *devtype,
+				    struct cs_timing_state *ts)
 {
 	u32 cs_idx, value[MAX_CS_REGS_COUNT];
 	int i, ret, reg_idx, num_regs;
+	struct cs_timing *cst;
 
 	if (WARN_ON(devtype->cs_regs_count > MAX_CS_REGS_COUNT))
 		return -EINVAL;
@@ -145,10 +158,23 @@ static int __init weim_timing_setup(struct device_node *np, void __iomem *base,
 		if (cs_idx >= devtype->cs_count)
 			return -EINVAL;
 
+		/* prevent re-configuring a CS that's already been configured */
+		cst = &ts->cs[cs_idx];
+		if (cst->is_applied && memcmp(value, cst->regs,
+					devtype->cs_regs_count*sizeof(u32))) {
+			dev_err(dev, "fsl,weim-cs-timing conflict on %pOF", np);
+			return -EINVAL;
+		}
+
 		/* set the timing for WEIM */
 		for (i = 0; i < devtype->cs_regs_count; i++)
 			writel(value[i],
 				base + cs_idx * devtype->cs_stride + i * 4);
+		if (!cst->is_applied) {
+			cst->is_applied = true;
+			memcpy(cst->regs, value,
+				devtype->cs_regs_count*sizeof(u32));
+		}
 	}
 
 	return 0;
@@ -165,6 +191,7 @@ static int __init weim_parse_dt(struct platform_device *pdev,
 	const struct imx_weim_devtype *devtype = of_id->data;
 	struct device_node *child;
 	int ret, have_child = 0;
+	struct cs_timing_state ts = {};
 
 	if (devtype == &imx50_weim_devtype) {
 		ret = imx_weim_gpr_setup(pdev);
@@ -179,7 +206,7 @@ static int __init weim_parse_dt(struct platform_device *pdev,
 	}
 
 	for_each_available_child_of_node(pdev->dev.of_node, child) {
-		ret = weim_timing_setup(child, base, devtype);
+		ret = weim_timing_setup(&pdev->dev, child, base, devtype, &ts);
 		if (ret)
 			dev_warn(&pdev->dev, "%pOF set timing failed.\n",
 				child);
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH 2/2] bus: imx-weim: guard against timing configuration conflicts
  2018-11-30 17:07 ` [PATCH 2/2] bus: imx-weim: guard against timing configuration conflicts thesven73
@ 2018-11-30 19:59   ` Rob Herring
  0 siblings, 0 replies; 4+ messages in thread
From: Rob Herring @ 2018-11-30 19:59 UTC (permalink / raw)
  To: Sven Van Asbroeck
  Cc: TheSven73, Shawn Guo, Kees Cook, Arnd Bergmann, linux-kernel

On Fri, Nov 30, 2018 at 11:08 AM <thesven73@gmail.com> wrote:
>
> From: Sven Van Asbroeck <TheSven73@googlemail.com>
>
> When adding weim child devices, there is a risk that the developer will
> (by mistake) specify more than one timing setting for the same chip select.
>
> The driver cannot support such a configuration.
>
> In case of conflict, this patch will print a warning to the log,
> and will ignore the child node in question.
>
> In this example, node acme@1 will be ignored, as it tries to modify
> timing settings for CS0:
>
> &weim {
>         acme@0 {

This should be '@0,0'

>                 compatible = "acme,whatever";
>                 reg = <0 0 0x100>;
>                 fsl,weim-cs-timing = <something>;
>         };
>         acme@1 {

And '@0,500'

>                 compatible = "acme,whatnot";
>                 reg = <0 0x500 0x100>;
>                 fsl,weim-cs-timing = <something else>;
>         };
> };
>
> However in this example, the driver will be happy:
>
> &weim {
>         acme@0 {
>                 compatible = "acme,whatever";
>                 reg = <0 0 0x100>;
>                 fsl,weim-cs-timing = <something>;
>         };
>         acme@1 {
>                 compatible = "acme,whatnot";
>                 reg = <0 0x500 0x100>;
>                 fsl,weim-cs-timing = <something>;
>         };
> };
>
> Signed-off-by: Sven Van Asbroeck <TheSven73@googlemail.com>
> ---
>  drivers/bus/imx-weim.c | 33 ++++++++++++++++++++++++++++++---
>  1 file changed, 30 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c
> index 24f22285395d..114e503ec785 100644
> --- a/drivers/bus/imx-weim.c
> +++ b/drivers/bus/imx-weim.c
> @@ -46,8 +46,18 @@ static const struct imx_weim_devtype imx51_weim_devtype = {
>  };
>
>  #define MAX_CS_REGS_COUNT      6
> +#define MAX_CS_REGS            6
>  #define OF_REG_SIZE            3
>
> +struct cs_timing {
> +       bool is_applied;
> +       u32 regs[MAX_CS_REGS_COUNT];
> +};
> +
> +struct cs_timing_state {
> +       struct cs_timing cs[MAX_CS_REGS];
> +};
> +
>  static const struct of_device_id weim_id_table[] = {
>         /* i.MX1/21 */
>         { .compatible = "fsl,imx1-weim", .data = &imx1_weim_devtype, },
> @@ -112,11 +122,14 @@ static int __init imx_weim_gpr_setup(struct platform_device *pdev)
>  }
>
>  /* Parse and set the timing for this device. */
> -static int __init weim_timing_setup(struct device_node *np, void __iomem *base,
> -                                   const struct imx_weim_devtype *devtype)
> +static int __init weim_timing_setup(struct device *dev,
> +                                   struct device_node *np, void __iomem *base,
> +                                   const struct imx_weim_devtype *devtype,
> +                                   struct cs_timing_state *ts)
>  {
>         u32 cs_idx, value[MAX_CS_REGS_COUNT];
>         int i, ret, reg_idx, num_regs;
> +       struct cs_timing *cst;
>
>         if (WARN_ON(devtype->cs_regs_count > MAX_CS_REGS_COUNT))
>                 return -EINVAL;
> @@ -145,10 +158,23 @@ static int __init weim_timing_setup(struct device_node *np, void __iomem *base,
>                 if (cs_idx >= devtype->cs_count)
>                         return -EINVAL;
>
> +               /* prevent re-configuring a CS that's already been configured */
> +               cst = &ts->cs[cs_idx];
> +               if (cst->is_applied && memcmp(value, cst->regs,
> +                                       devtype->cs_regs_count*sizeof(u32))) {
> +                       dev_err(dev, "fsl,weim-cs-timing conflict on %pOF", np);
> +                       return -EINVAL;
> +               }
> +
>                 /* set the timing for WEIM */
>                 for (i = 0; i < devtype->cs_regs_count; i++)
>                         writel(value[i],
>                                 base + cs_idx * devtype->cs_stride + i * 4);
> +               if (!cst->is_applied) {
> +                       cst->is_applied = true;
> +                       memcpy(cst->regs, value,
> +                               devtype->cs_regs_count*sizeof(u32));
> +               }
>         }
>
>         return 0;
> @@ -165,6 +191,7 @@ static int __init weim_parse_dt(struct platform_device *pdev,
>         const struct imx_weim_devtype *devtype = of_id->data;
>         struct device_node *child;
>         int ret, have_child = 0;
> +       struct cs_timing_state ts = {};
>
>         if (devtype == &imx50_weim_devtype) {
>                 ret = imx_weim_gpr_setup(pdev);
> @@ -179,7 +206,7 @@ static int __init weim_parse_dt(struct platform_device *pdev,
>         }
>
>         for_each_available_child_of_node(pdev->dev.of_node, child) {
> -               ret = weim_timing_setup(child, base, devtype);
> +               ret = weim_timing_setup(&pdev->dev, child, base, devtype, &ts);
>                 if (ret)
>                         dev_warn(&pdev->dev, "%pOF set timing failed.\n",
>                                 child);
> --
> 2.17.1
>

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2018-11-30 19:59 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-11-30 17:07 [PATCH 0/2] bus: imx-weim thesven73
2018-11-30 17:07 ` [PATCH 1/2] bus: imx-weim: support multiple address ranges per child node thesven73
2018-11-30 17:07 ` [PATCH 2/2] bus: imx-weim: guard against timing configuration conflicts thesven73
2018-11-30 19:59   ` Rob Herring

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