[PATCH v2 1/2] dt-bindings: fpga: xilinx-slave-serial: add optional INIT_B GPIO

[PATCH v2 1/2] dt-bindings: fpga: xilinx-slave-serial: add optional INIT_B GPIO

[Luca Ceresoli]

The INIT_B is used by the 6 and 7 series to report the programming status,
providing more control and information about programming errors.

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>

---

Changes in v2:
 - rename init_b-gpios to init-b-gpios (Rob Herring suggested to not use '_'
   in property names)
---
 .../devicetree/bindings/fpga/xilinx-slave-serial.txt       | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/fpga/xilinx-slave-serial.txt b/Documentation/devicetree/bindings/fpga/xilinx-slave-serial.txt
index 9f103f3872e8..5ef659c1394d 100644
--- a/Documentation/devicetree/bindings/fpga/xilinx-slave-serial.txt
+++ b/Documentation/devicetree/bindings/fpga/xilinx-slave-serial.txt
@@ -16,6 +16,10 @@ Required properties:
 - prog_b-gpios: config pin (referred to as PROGRAM_B in the manual)
 - done-gpios: config status pin (referred to as DONE in the manual)
 
+Optional properties:
+- init-b-gpios: initialization status and configuration error pin
+                (referred to as INIT_B in the manual)
+
 Example for full FPGA configuration:
 
 	fpga-region0 {
@@ -40,7 +44,8 @@ Example for full FPGA configuration:
 			spi-max-frequency = <60000000>;
 			spi-cpha;
 			reg = <0>;
-			done-gpios = <&gpio0 9 GPIO_ACTIVE_HIGH>;
 			prog_b-gpios = <&gpio0 29 GPIO_ACTIVE_LOW>;
+			init-b-gpios = <&gpio0 28 GPIO_ACTIVE_LOW>;
+			done-gpios = <&gpio0 9 GPIO_ACTIVE_HIGH>;
 		};
 	};
-- 
2.27.0

[PATCH v2 2/2] fpga manager: xilinx-spi: check INIT_B pin during write_init

[Luca Ceresoli]

The INIT_B pin reports the status during startup and after the end of the
programming process. However the current driver completely ignores it.

Check the pin status during startup to make sure programming is never
started too early and also to detect any hardware issues in the FPGA
connection.

This is optional for backward compatibility. If INIT_B is not passed by
device tree, just fallback to the old udelays.

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>

---

Changes in v2:
 - rename DT property init_b-gpios to init-b-gpios (Rob Herring suggested to
   not use '_' in property names)
 - improve wait_for_init_b() documentation and variable naming
---
 drivers/fpga/xilinx-spi.c | 55 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 54 insertions(+), 1 deletion(-)

diff --git a/drivers/fpga/xilinx-spi.c b/drivers/fpga/xilinx-spi.c
index 799ae04301be..2967aa2a74e2 100644
--- a/drivers/fpga/xilinx-spi.c
+++ b/drivers/fpga/xilinx-spi.c
@@ -23,6 +23,7 @@
 struct xilinx_spi_conf {
 	struct spi_device *spi;
 	struct gpio_desc *prog_b;
+	struct gpio_desc *init_b;
 	struct gpio_desc *done;
 };
 
@@ -36,11 +37,45 @@ static enum fpga_mgr_states xilinx_spi_state(struct fpga_manager *mgr)
 	return FPGA_MGR_STATE_UNKNOWN;
 }
 
+/**
+ * wait_for_init_b - wait for the INIT_B pin to have a given state, or wait
+ * a given delay if the pin is unavailable
+ *
+ * @mgr:        The FPGA manager object
+ * @value:      Value INIT_B to wait for (1 = asserted = low)
+ * @alt_udelay: Delay to wait if the INIT_B GPIO is not available
+ *
+ * Returns 0 when the INIT_B GPIO reached the given state or -ETIMEDOUT if
+ * too much time passed waiting for that. If no INIT_B GPIO is available
+ * then always return 0.
+ */
+static int wait_for_init_b(struct fpga_manager *mgr, int value,
+			   unsigned long alt_udelay)
+{
+	struct xilinx_spi_conf *conf = mgr->priv;
+	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
+
+	if (conf->init_b) {
+		while (time_before(jiffies, timeout)) {
+			/* dump_state(conf, "wait for init_d .."); */
+			if (gpiod_get_value(conf->init_b) == value)
+				return 0;
+			usleep_range(100, 400);
+		}
+		return -ETIMEDOUT;
+	}
+
+	udelay(alt_udelay);
+
+	return 0;
+}
+
 static int xilinx_spi_write_init(struct fpga_manager *mgr,
 				 struct fpga_image_info *info,
 				 const char *buf, size_t count)
 {
 	struct xilinx_spi_conf *conf = mgr->priv;
+	int err;
 
 	if (info->flags & FPGA_MGR_PARTIAL_RECONFIG) {
 		dev_err(&mgr->dev, "Partial reconfiguration not supported.\n");
@@ -49,10 +84,21 @@ static int xilinx_spi_write_init(struct fpga_manager *mgr,
 
 	gpiod_set_value(conf->prog_b, 1);
 
-	udelay(1); /* min is 500 ns */
+	err = wait_for_init_b(mgr, 1, 1); /* min is 500 ns */
+	if (err) {
+		dev_err(&mgr->dev, "INIT_B pin did not go low\n");
+		gpiod_set_value(conf->prog_b, 0);
+		return err;
+	}
 
 	gpiod_set_value(conf->prog_b, 0);
 
+	err = wait_for_init_b(mgr, 0, 0);
+	if (err) {
+		dev_err(&mgr->dev, "INIT_B pin did not go high\n");
+		return err;
+	}
+
 	if (gpiod_get_value(conf->done)) {
 		dev_err(&mgr->dev, "Unexpected DONE pin state...\n");
 		return -EIO;
@@ -154,6 +200,13 @@ static int xilinx_spi_probe(struct spi_device *spi)
 		return PTR_ERR(conf->prog_b);
 	}
 
+	conf->init_b = devm_gpiod_get_optional(&spi->dev, "init-b", GPIOD_IN);
+	if (IS_ERR(conf->init_b)) {
+		dev_err(&spi->dev, "Failed to get INIT_B gpio: %ld\n",
+			PTR_ERR(conf->init_b));
+		return PTR_ERR(conf->init_b);
+	}
+
 	conf->done = devm_gpiod_get(&spi->dev, "done", GPIOD_IN);
 	if (IS_ERR(conf->done)) {
 		dev_err(&spi->dev, "Failed to get DONE gpio: %ld\n",
-- 
2.27.0

Re: [PATCH v2 1/2] dt-bindings: fpga: xilinx-slave-serial: add optional INIT_B GPIO

[Moritz Fischer]

On Mon, Jun 22, 2020 at 03:37:22PM +0200, Luca Ceresoli wrote:
> The INIT_B is used by the 6 and 7 series to report the programming status,
> providing more control and information about programming errors.
> 
> Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
> 
> ---
> 
> Changes in v2:
>  - rename init_b-gpios to init-b-gpios (Rob Herring suggested to not use '_'
>    in property names)
> ---
>  .../devicetree/bindings/fpga/xilinx-slave-serial.txt       | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/fpga/xilinx-slave-serial.txt b/Documentation/devicetree/bindings/fpga/xilinx-slave-serial.txt
> index 9f103f3872e8..5ef659c1394d 100644
> --- a/Documentation/devicetree/bindings/fpga/xilinx-slave-serial.txt
> +++ b/Documentation/devicetree/bindings/fpga/xilinx-slave-serial.txt
> @@ -16,6 +16,10 @@ Required properties:
>  - prog_b-gpios: config pin (referred to as PROGRAM_B in the manual)
>  - done-gpios: config status pin (referred to as DONE in the manual)
>  
> +Optional properties:
> +- init-b-gpios: initialization status and configuration error pin
> +                (referred to as INIT_B in the manual)
> +
>  Example for full FPGA configuration:
>  
>  	fpga-region0 {
> @@ -40,7 +44,8 @@ Example for full FPGA configuration:
>  			spi-max-frequency = <60000000>;
>  			spi-cpha;
>  			reg = <0>;
> -			done-gpios = <&gpio0 9 GPIO_ACTIVE_HIGH>;
>  			prog_b-gpios = <&gpio0 29 GPIO_ACTIVE_LOW>;
> +			init-b-gpios = <&gpio0 28 GPIO_ACTIVE_LOW>;
> +			done-gpios = <&gpio0 9 GPIO_ACTIVE_HIGH>;
>  		};
>  	};
> -- 
> 2.27.0
> 

Will apply to for-next,

Thanks!

Re: [PATCH v2 2/2] fpga manager: xilinx-spi: check INIT_B pin during write_init

[Moritz Fischer]

On Mon, Jun 22, 2020 at 03:37:23PM +0200, Luca Ceresoli wrote:
> The INIT_B pin reports the status during startup and after the end of the
> programming process. However the current driver completely ignores it.
> 
> Check the pin status during startup to make sure programming is never
> started too early and also to detect any hardware issues in the FPGA
> connection.
> 
> This is optional for backward compatibility. If INIT_B is not passed by
> device tree, just fallback to the old udelays.
> 
> Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
> 
> ---
> 
> Changes in v2:
>  - rename DT property init_b-gpios to init-b-gpios (Rob Herring suggested to
>    not use '_' in property names)
>  - improve wait_for_init_b() documentation and variable naming
> ---
>  drivers/fpga/xilinx-spi.c | 55 ++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 54 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/fpga/xilinx-spi.c b/drivers/fpga/xilinx-spi.c
> index 799ae04301be..2967aa2a74e2 100644
> --- a/drivers/fpga/xilinx-spi.c
> +++ b/drivers/fpga/xilinx-spi.c
> @@ -23,6 +23,7 @@
>  struct xilinx_spi_conf {
>  	struct spi_device *spi;
>  	struct gpio_desc *prog_b;
> +	struct gpio_desc *init_b;
>  	struct gpio_desc *done;
>  };
>  
> @@ -36,11 +37,45 @@ static enum fpga_mgr_states xilinx_spi_state(struct fpga_manager *mgr)
>  	return FPGA_MGR_STATE_UNKNOWN;
>  }
>  
> +/**
> + * wait_for_init_b - wait for the INIT_B pin to have a given state, or wait
> + * a given delay if the pin is unavailable
> + *
> + * @mgr:        The FPGA manager object
> + * @value:      Value INIT_B to wait for (1 = asserted = low)
> + * @alt_udelay: Delay to wait if the INIT_B GPIO is not available
> + *
> + * Returns 0 when the INIT_B GPIO reached the given state or -ETIMEDOUT if
> + * too much time passed waiting for that. If no INIT_B GPIO is available
> + * then always return 0.
> + */
> +static int wait_for_init_b(struct fpga_manager *mgr, int value,
> +			   unsigned long alt_udelay)
> +{
> +	struct xilinx_spi_conf *conf = mgr->priv;
> +	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
> +
> +	if (conf->init_b) {
> +		while (time_before(jiffies, timeout)) {
> +			/* dump_state(conf, "wait for init_d .."); */
> +			if (gpiod_get_value(conf->init_b) == value)
> +				return 0;
> +			usleep_range(100, 400);
> +		}
> +		return -ETIMEDOUT;
> +	}
> +
> +	udelay(alt_udelay);
> +
> +	return 0;
> +}
> +
>  static int xilinx_spi_write_init(struct fpga_manager *mgr,
>  				 struct fpga_image_info *info,
>  				 const char *buf, size_t count)
>  {
>  	struct xilinx_spi_conf *conf = mgr->priv;
> +	int err;
>  
>  	if (info->flags & FPGA_MGR_PARTIAL_RECONFIG) {
>  		dev_err(&mgr->dev, "Partial reconfiguration not supported.\n");
> @@ -49,10 +84,21 @@ static int xilinx_spi_write_init(struct fpga_manager *mgr,
>  
>  	gpiod_set_value(conf->prog_b, 1);
>  
> -	udelay(1); /* min is 500 ns */
> +	err = wait_for_init_b(mgr, 1, 1); /* min is 500 ns */
> +	if (err) {
> +		dev_err(&mgr->dev, "INIT_B pin did not go low\n");
> +		gpiod_set_value(conf->prog_b, 0);
> +		return err;
> +	}
>  
>  	gpiod_set_value(conf->prog_b, 0);
>  
> +	err = wait_for_init_b(mgr, 0, 0);
> +	if (err) {
> +		dev_err(&mgr->dev, "INIT_B pin did not go high\n");
> +		return err;
> +	}
> +
>  	if (gpiod_get_value(conf->done)) {
>  		dev_err(&mgr->dev, "Unexpected DONE pin state...\n");
>  		return -EIO;
> @@ -154,6 +200,13 @@ static int xilinx_spi_probe(struct spi_device *spi)
>  		return PTR_ERR(conf->prog_b);
>  	}
>  
> +	conf->init_b = devm_gpiod_get_optional(&spi->dev, "init-b", GPIOD_IN);
> +	if (IS_ERR(conf->init_b)) {
> +		dev_err(&spi->dev, "Failed to get INIT_B gpio: %ld\n",
> +			PTR_ERR(conf->init_b));
> +		return PTR_ERR(conf->init_b);
> +	}
> +
>  	conf->done = devm_gpiod_get(&spi->dev, "done", GPIOD_IN);
>  	if (IS_ERR(conf->done)) {
>  		dev_err(&spi->dev, "Failed to get DONE gpio: %ld\n",
> -- 
> 2.27.0
> 

Will apply to for-next,

Thanks!