[v2,1/2] doc: Add bindings document for Xilinx LogiCore PR Decoupler

This adds the binding documentation for the Xilinx LogiCORE PR
Decoupler soft core.

Signed-off-by: Moritz Fischer <mdf@kernel.org>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Sören Brinkmann <soren.brinkmann@xilinx.com>
Cc: linux-kernel@vger.kernel.org
Cc: devicetree@vger.kernel.org
---

Changes from v1:
- Added clock names & clock to example
- Merged some of the description from Michal's version

---
 .../bindings/fpga/xilinx-pr-decoupler.txt          | 32 ++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/fpga/xilinx-pr-decoupler.txt

On 17.3.2017 01:51, Moritz Fischer wrote:
> This adds the binding documentation for the Xilinx LogiCORE PR
> Decoupler soft core.
> 
> Signed-off-by: Moritz Fischer <mdf@kernel.org>
> Cc: Michal Simek <michal.simek@xilinx.com>
> Cc: Sören Brinkmann <soren.brinkmann@xilinx.com>
> Cc: linux-kernel@vger.kernel.org
> Cc: devicetree@vger.kernel.org
> ---
> 
> Changes from v1:
> - Added clock names & clock to example
> - Merged some of the description from Michal's version
> 
> ---
>  .../bindings/fpga/xilinx-pr-decoupler.txt          | 32 ++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/fpga/xilinx-pr-decoupler.txt
> 
> diff --git a/Documentation/devicetree/bindings/fpga/xilinx-pr-decoupler.txt b/Documentation/devicetree/bindings/fpga/xilinx-pr-decoupler.txt
> new file mode 100644
> index 0000000..2080006
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/fpga/xilinx-pr-decoupler.txt
> @@ -0,0 +1,32 @@
> +Xilinx LogiCORE Partial Reconfig Decoupler Softcore
> +
> +The Xilinx LogiCORE Partial Reconfig Decoupler manages one or more
> +decouplers / fpga bridges.
> +The controller can decouple/disable the bridges which prevents signal
> +changes from passing through the bridge.  The controller can also
> +couple / enable the bridges which allows traffic to pass through the
> +bridge normally.
> +
> +The Driver supports only MMIO handling. A PR region can have multiple
> +PR Decouples which can bhe handled independently or chaines via decouple/
> +decouple_status signals.
> +
> +Required properties:
> +- compatible		: Should contain "xlnx,pr-decoupler-1.00"

should

I would tend to do this as
"xlnx,pr-decoupler-1.00" and/or  "xlnx,pr_decoupler"


> +- regs			: base address and size for decoupler module
> +- clocks		: input clock to IP
> +- clock-names		: should contain "aclk"
> +
> +Optional properties:
> +- bridge-enable		: 0 if driver should disable bridge at startup
> +			  1 if driver should enable bridge at startup
> +			  Default is to leave bridge in current state.

Interesting that this is not a bool.
But anyway this should be link to bridge binding because I expect this
is the same for all.

> +
> +Example:
> +	fpga-bridge@100000450 {
> +		compatible = "xlnx,pr-decoupler-1.00";

"xlnx,pr-decoupler-1.00", "xlnx,pr_decoupler";

> +		regs = <0x1000 0x10>;
> +		clocks = <&clkc 15>;
> +		clock-names = "aclk";
> +		bridge-enable = <0>;
> +	};
> 

Thanks,
Michal

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On 17.3.2017 01:51, Moritz Fischer wrote:
> This adds support for the Xilinx LogiCORE PR Decoupler
> soft-ip that does decoupling of PR regions in the FPGA
> fabric during partial reconfiguration.
> 
> Signed-off-by: Moritz Fischer <mdf@kernel.org>
> Cc: Michal Simek <michal.simek@xilinx.com>
> Cc: Sören Brinkmann <soren.brinkmann@xilinx.com>
> Cc: linux-kernel@vger.kernel.org
> Cc: devicetree@vger.kernel.org
> ---
> 
> Changes from v1:
> - Added Michal as Co-Author since I pulled in some of his code
> - Reworked clk handling in _remove()
> - Pulled in Michal's version of show_enable(), ditched priv->enabled
> 
> ---
>  drivers/fpga/Kconfig               |   9 +++
>  drivers/fpga/Makefile              |   1 +
>  drivers/fpga/xilinx-pr-decoupler.c | 147 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 157 insertions(+)
>  create mode 100644 drivers/fpga/xilinx-pr-decoupler.c
> 
> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> index 967cda4..e42c7dc 100644
> --- a/drivers/fpga/Kconfig
> +++ b/drivers/fpga/Kconfig
> @@ -69,6 +69,15 @@ config ALTERA_FREEZE_BRIDGE
>  	  isolate one region of the FPGA from the busses while that
>  	  region is being reprogrammed.
>  
> +config XILINX_PR_DECOUPLER
> +	tristate "Xilinx LogiCORE PR Decoupler"
> +	depends on FPGA_BRIDGE
> +	help
> +	  Say Y to enable drivers for Xilinx LogiCORE PR Decoupler.
> +	  The PR Decoupler exists in the FPGA fabric to isolate one
> +	  region of the FPGA from the busses while that region is
> +	  being reprogrammed during partial reconfig.
> +
>  endif # FPGA
>  
>  endmenu
> diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
> index cc0d364..3f04bcf 100644
> --- a/drivers/fpga/Makefile
> +++ b/drivers/fpga/Makefile
> @@ -15,6 +15,7 @@ obj-$(CONFIG_FPGA_MGR_ZYNQ_FPGA)	+= zynq-fpga.o
>  obj-$(CONFIG_FPGA_BRIDGE)		+= fpga-bridge.o
>  obj-$(CONFIG_SOCFPGA_FPGA_BRIDGE)	+= altera-hps2fpga.o altera-fpga2sdram.o
>  obj-$(CONFIG_ALTERA_FREEZE_BRIDGE)	+= altera-freeze-bridge.o
> +obj-$(CONFIG_XILINX_PR_DECOUPLER)	+= xilinx-pr-decoupler.o
>  
>  # High Level Interfaces
>  obj-$(CONFIG_FPGA_REGION)		+= fpga-region.o
> diff --git a/drivers/fpga/xilinx-pr-decoupler.c b/drivers/fpga/xilinx-pr-decoupler.c
> new file mode 100644
> index 0000000..761700c
> --- /dev/null
> +++ b/drivers/fpga/xilinx-pr-decoupler.c
> @@ -0,0 +1,147 @@
> +/*
> + * Copyright (c) 2017, National Instruments Corp.
> + * Copyright (c) 2017, Xilix Inc
> + *
> + * FPGA Bridge Driver for the Xilinx LogiCORE Partial Reconfiguration
> + * Decoupler IP Core.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; version 2 of the License.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/of_device.h>
> +#include <linux/module.h>
> +#include <linux/fpga/fpga-bridge.h>
> +
> +#define CTRL_CMD_DECOUPLE	BIT(0)
> +#define CTRL_CMD_COUPLE		~BIT(0)
> +
> +struct xlnx_pr_decoupler_data {
> +	void __iomem *io_base;
> +	struct clk *clk;
> +};
> +
> +static int xlnx_pr_decoupler_enable_set(struct fpga_bridge *bridge, bool enable)
> +{
> +	int err;
> +	struct xlnx_pr_decoupler_data *priv = bridge->priv;
> +
> +	err = clk_enable(priv->clk);
> +	if (err)
> +		return err;
> +
> +	if (enable)
> +		writel(CTRL_CMD_COUPLE, priv->io_base);
> +	else
> +		writel(CTRL_CMD_DECOUPLE, priv->io_base);
> +
> +	clk_disable(priv->clk);
> +
> +	return 0;
> +}
> +
> +static int xlnx_pr_decoupler_enable_show(struct fpga_bridge *bridge)
> +{
> +	const struct xlnx_pr_decoupler_data *priv = bridge->priv;
> +	u32 status;
> +	int err;
> +
> +	err = clk_enable(priv->clk);
> +	if (err)
> +		return err;
> +
> +	status = readl(priv->io_base);
> +
> +	clk_disable(priv->clk);
> +
> +	return !status;
> +}
> +
> +static struct fpga_bridge_ops xlnx_pr_decoupler_br_ops = {
> +	.enable_set = xlnx_pr_decoupler_enable_set,
> +	.enable_show = xlnx_pr_decoupler_enable_show,
> +};
> +
> +static const struct of_device_id xlnx_pr_decoupler_of_match[] = {
> +	{ .compatible = "xlnx,pr-decoupler-1.00", },

I would add here that generic compatible string too.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

Thanks,
Michal
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