fpga manager: Adding FPGA Manager support for Xilinx Zynq 7000

This commit adds FPGA Manager support for the Xilinx Zynq chip.
The code borrows some from the xdevcfg driver in Xilinx'
vendor tree.

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 539 insertions, 0 deletions

diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
index dfc1f1ec093b..c9b9fdf6cfbb 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -19,6 +19,11 @@ config FPGA_MGR_SOCFPGA
 	help
 	  FPGA manager driver support for Altera SOCFPGA.
 
+config FPGA_MGR_ZYNQ_FPGA
+	tristate "Xilinx Zynq FPGA"
+	help
+	  FPGA manager driver support for Xilinx Zynq FPGAs.
+
 endif # FPGA
 
 endmenu
diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
index ba6c5c597a4d..8d83fc6b1613 100644
--- a/drivers/fpga/Makefile
+++ b/drivers/fpga/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_FPGA)			+= fpga-mgr.o
 
 # FPGA Manager Drivers
 obj-$(CONFIG_FPGA_MGR_SOCFPGA)		+= socfpga.o
+obj-$(CONFIG_FPGA_MGR_ZYNQ_FPGA)	+= zynq-fpga.o
diff --git a/drivers/fpga/zynq-fpga.c b/drivers/fpga/zynq-fpga.c
new file mode 100644
index 000000000000..103303c88937
--- /dev/null
+++ b/drivers/fpga/zynq-fpga.c
@@ -0,0 +1,533 @@
+/*
+ * Copyright (c) 2011-2015 Xilinx Inc.
+ * Copyright (c) 2015, National Instruments Corp.
+ *
+ * FPGA Manager Driver for Xilinx Zynq, heavily based on xdevcfg driver
+ * in their vendor tree.
+ *
+ * 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/completion.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/fpga/fpga-mgr.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/pm.h>
+#include <linux/regmap.h>
+#include <linux/string.h>
+
+/* Offsets into SLCR regmap */
+
+/* FPGA Software Reset Control */
+#define SLCR_FPGA_RST_CTRL_OFFSET	0x240
+/* Level Shifters Enable */
+#define SLCR_LVL_SHFTR_EN_OFFSET	0x900
+
+/* Constant Definitions */
+
+/* Control Register */
+#define CTRL_OFFSET			0x00
+/* Lock Register */
+#define LOCK_OFFSET			0x04
+/* Interrupt Status Register */
+#define INT_STS_OFFSET			0x0c
+/* Interrupt Mask Register */
+#define INT_MASK_OFFSET			0x10
+/* Status Register */
+#define STATUS_OFFSET			0x14
+/* DMA Source Address Register */
+#define DMA_SRC_ADDR_OFFSET		0x18
+/* DMA Destination Address Reg */
+#define DMA_DST_ADDR_OFFSET		0x1c
+/* DMA Source Transfer Length */
+#define DMA_SRC_LEN_OFFSET		0x20
+/* DMA Destination Transfer */
+#define DMA_DEST_LEN_OFFSET		0x24
+/* Unlock Register */
+#define UNLOCK_OFFSET			0x34
+/* Misc. Control Register */
+#define MCTRL_OFFSET			0x80
+
+/* Control Register Bit definitions */
+
+/* Signal to reset FPGA */
+#define CTRL_PCFG_PROG_B_MASK		BIT(30)
+/* Enable PCAP for PR */
+#define CTRL_PCAP_PR_MASK		BIT(27)
+/* Enable PCAP */
+#define CTRL_PCAP_MODE_MASK		BIT(26)
+
+/* Miscellaneous Control Register bit definitions */
+/* Internal PCAP loopback */
+#define MCTRL_PCAP_LPBK_MASK		BIT(4)
+
+/* Status register bit definitions */
+
+/* FPGA init status */
+#define STATUS_DMA_Q_F			BIT(31)
+#define STATUS_PCFG_INIT_MASK		BIT(4)
+
+/* Interrupt Status/Mask Register Bit definitions */
+/* DMA command done */
+#define IXR_DMA_DONE_MASK		BIT(13)
+/* DMA and PCAP cmd done */
+#define IXR_D_P_DONE_MASK		BIT(12)
+ /* FPGA programmed */
+#define IXR_PCFG_DONE_MASK		BIT(2)
+#define IXR_ERROR_FLAGS_MASK		0x00F0F860
+#define IXR_ALL_MASK			0xF8F7F87F
+
+/* Miscellaneous constant values */
+
+/* Invalid DMA addr */
+#define DMA_INVALID_ADDRESS		GENMASK(31, 0)
+/* Used to unlock the dev */
+#define UNLOCK_MASK			0x757bdf0d
+/* Timeout for DMA to complete */
+#define DMA_DONE_TIMEOUT		msecs_to_jiffies(1000)
+/* Timeout for polling reset bits */
+#define INIT_POLL_TIMEOUT		2500000
+/* Delay for polling reset bits */
+#define INIT_POLL_DELAY			20
+
+/* Masks for controlling stuff in SLCR */
+/* Disable all Level shifters */
+#define LVL_SHFTR_DISABLE_ALL_MASK	0x0
+/* Enable Level shifters from PS to PL */
+#define LVL_SHFTR_ENABLE_PS_TO_PL	0xa
+/* Enable Level shifters from PL to PS */
+#define LVL_SHFTR_ENABLE_PL_TO_PS	0xf
+/* Enable global resets */
+#define FPGA_RST_ALL_MASK		0xf
+/* Disable global resets */
+#define FPGA_RST_NONE_MASK		0x0
+
+struct zynq_fpga_priv {
+	struct device *dev;
+	int irq;
+	struct clk *clk;
+
+	void __iomem *io_base;
+	struct regmap *slcr;
+
+	struct completion dma_done;
+};
+
+static inline void zynq_fpga_write(struct zynq_fpga_priv *priv, u32 offset,
+				   u32 val)
+{
+	writel(val, priv->io_base + offset);
+}
+
+static inline u32 zynq_fpga_read(const struct zynq_fpga_priv *priv,
+				 u32 offset)
+{
+	return readl(priv->io_base + offset);
+}
+
+#define zynq_fpga_poll_timeout(priv, addr, val, cond, sleep_us, timeout_us) \
+	readl_poll_timeout(priv->io_base + addr, val, cond, sleep_us, \
+			   timeout_us)
+
+static void zynq_fpga_mask_irqs(struct zynq_fpga_priv *priv)
+{
+	u32 intr_mask;
+
+	intr_mask = zynq_fpga_read(priv, INT_MASK_OFFSET);
+	zynq_fpga_write(priv, INT_MASK_OFFSET,
+			intr_mask | IXR_DMA_DONE_MASK | IXR_ERROR_FLAGS_MASK);
+}
+
+static void zynq_fpga_unmask_irqs(struct zynq_fpga_priv *priv)
+{
+	u32 intr_mask;
+
+	intr_mask = zynq_fpga_read(priv, INT_MASK_OFFSET);
+	zynq_fpga_write(priv, INT_MASK_OFFSET,
+			intr_mask
+			& ~(IXR_D_P_DONE_MASK | IXR_ERROR_FLAGS_MASK));
+}
+
+static irqreturn_t zynq_fpga_isr(int irq, void *data)
+{
+	struct zynq_fpga_priv *priv = data;
+
+	/* disable DMA and error IRQs */
+	zynq_fpga_mask_irqs(priv);
+
+	complete(&priv->dma_done);
+
+	return IRQ_HANDLED;
+}
+
+static int zynq_fpga_ops_write_init(struct fpga_manager *mgr, u32 flags,
+				    const char *buf, size_t count)
+{
+	struct zynq_fpga_priv *priv;
+	u32 ctrl, status;
+	int err;
+
+	priv = mgr->priv;
+
+	err = clk_enable(priv->clk);
+	if (err)
+		return err;
+
+	/* don't globally reset PL if we're doing partial reconfig */
+	if (!(flags & FPGA_MGR_PARTIAL_RECONFIG)) {
+		/* assert AXI interface resets */
+		regmap_write(priv->slcr, SLCR_FPGA_RST_CTRL_OFFSET,
+			     FPGA_RST_ALL_MASK);
+
+		/* disable all level shifters */
+		regmap_write(priv->slcr, SLCR_LVL_SHFTR_EN_OFFSET,
+			     LVL_SHFTR_DISABLE_ALL_MASK);
+		/* enable level shifters from PS to PL */
+		regmap_write(priv->slcr, SLCR_LVL_SHFTR_EN_OFFSET,
+			     LVL_SHFTR_ENABLE_PS_TO_PL);
+
+		/* create a rising edge on PCFG_INIT. PCFG_INIT follows
+		 * PCFG_PROG_B, so we need to poll it after setting PCFG_PROG_B
+		 * to make sure the rising edge actually happens.
+		 * Note: PCFG_PROG_B is low active, sequence as described in
+		 * UG585 v1.10 page 211
+		 */
+		ctrl = zynq_fpga_read(priv, CTRL_OFFSET);
+		ctrl |= CTRL_PCFG_PROG_B_MASK;
+
+		zynq_fpga_write(priv, CTRL_OFFSET, ctrl);
+
+		err = zynq_fpga_poll_timeout(priv, STATUS_OFFSET, status,
+					     status & STATUS_PCFG_INIT_MASK,
+					     INIT_POLL_DELAY,
+					     INIT_POLL_TIMEOUT);
+		if (err) {
+			dev_err(priv->dev, "Timeout waiting for PCFG_INIT");
+			goto out_err;
+		}
+
+		ctrl = zynq_fpga_read(priv, CTRL_OFFSET);
+		ctrl &= ~CTRL_PCFG_PROG_B_MASK;
+
+		zynq_fpga_write(priv, CTRL_OFFSET, ctrl);
+
+		err = zynq_fpga_poll_timeout(priv, STATUS_OFFSET, status,
+					     !(status & STATUS_PCFG_INIT_MASK),
+					     INIT_POLL_DELAY,
+					     INIT_POLL_TIMEOUT);
+		if (err) {
+			dev_err(priv->dev, "Timeout waiting for !PCFG_INIT");
+			goto out_err;
+		}
+
+		ctrl = zynq_fpga_read(priv, CTRL_OFFSET);
+		ctrl |= CTRL_PCFG_PROG_B_MASK;
+
+		zynq_fpga_write(priv, CTRL_OFFSET, ctrl);
+
+		err = zynq_fpga_poll_timeout(priv, STATUS_OFFSET, status,
+					     status & STATUS_PCFG_INIT_MASK,
+					     INIT_POLL_DELAY,
+					     INIT_POLL_TIMEOUT);
+		if (err) {
+			dev_err(priv->dev, "Timeout waiting for PCFG_INIT");
+			goto out_err;
+		}
+	}
+
+	/* set configuration register with following options:
+	 * - enable PCAP interface
+	 * - set throughput for maximum speed
+	 * - set CPU in user mode
+	 */
+	ctrl = zynq_fpga_read(priv, CTRL_OFFSET);
+	zynq_fpga_write(priv, CTRL_OFFSET,
+			(CTRL_PCAP_PR_MASK | CTRL_PCAP_MODE_MASK | ctrl));
+
+	/* check that we have room in the command queue */
+	status = zynq_fpga_read(priv, STATUS_OFFSET);
+	if (status & STATUS_DMA_Q_F) {
+		dev_err(priv->dev, "DMA command queue full");
+		err = -EBUSY;
+		goto out_err;
+	}
+
+	/* ensure internal PCAP loopback is disabled */
+	ctrl = zynq_fpga_read(priv, MCTRL_OFFSET);
+	zynq_fpga_write(priv, MCTRL_OFFSET, (~MCTRL_PCAP_LPBK_MASK & ctrl));
+
+	clk_disable(priv->clk);
+
+	return 0;
+
+out_err:
+	clk_disable(priv->clk);
+
+	return err;
+}
+
+static int zynq_fpga_ops_write(struct fpga_manager *mgr,
+			       const char *buf, size_t count)
+{
+	struct zynq_fpga_priv *priv;
+	int err;
+	char *kbuf;
+	size_t i, in_count;
+	dma_addr_t dma_addr;
+	u32 transfer_length = 0;
+	u32 intr_status;
+
+	in_count = count;
+	priv = mgr->priv;
+
+	kbuf = dma_alloc_coherent(priv->dev, count, &dma_addr, GFP_KERNEL);
+	if (!kbuf)
+		return -ENOMEM;
+
+	memcpy(kbuf, buf, count);
+
+	/* look for the sync word */
+	for (i = 0; i < count - 4; i++) {
+		if (memcmp(kbuf + i, "\xAA\x99\x55\x66", 4) == 0) {
+			dev_dbg(priv->dev, "Found swapped sync word\n");
+			break;
+		}
+	}
+
+	/* remove the header, align the data on word boundary */
+	if (i != count - 4) {
+		count -= i;
+		memmove(kbuf, kbuf + i, count);
+	}
+
+	/* fixup endianness of the data */
+	for (i = 0; i < count; i += 4) {
+		u32 *p = (u32 *)&kbuf[i];
+		*p = swab32(*p);
+	}
+
+	/* enable clock */
+	err = clk_enable(priv->clk);
+	if (err)
+		goto out_free;
+
+	zynq_fpga_write(priv, INT_STS_OFFSET, IXR_ALL_MASK);
+
+	reinit_completion(&priv->dma_done);
+
+	/* enable DMA and error IRQs */
+	zynq_fpga_unmask_irqs(priv);
+
+	/* the +1 in the src addr is used to hold off on DMA_DONE IRQ
+	 * until both AXI and PCAP are done ...
+	 */
+	zynq_fpga_write(priv, DMA_SRC_ADDR_OFFSET, (u32)(dma_addr) + 1);
+	zynq_fpga_write(priv, DMA_DST_ADDR_OFFSET, (u32)DMA_INVALID_ADDRESS);
+
+	/* convert #bytes to #words */
+	transfer_length = (count + 3) / 4;
+
+	zynq_fpga_write(priv, DMA_SRC_LEN_OFFSET, transfer_length);
+	zynq_fpga_write(priv, DMA_DEST_LEN_OFFSET, 0);
+
+	wait_for_completion(&priv->dma_done);
+
+	intr_status = zynq_fpga_read(priv, INT_STS_OFFSET);
+	zynq_fpga_write(priv, INT_STS_OFFSET, intr_status);
+
+	if (!((intr_status & IXR_D_P_DONE_MASK) == IXR_D_P_DONE_MASK)) {
+		dev_err(priv->dev, "Error configuring FPGA");
+		err = -EFAULT;
+	}
+
+	clk_disable(priv->clk);
+
+out_free:
+	dma_free_coherent(priv->dev, in_count, kbuf, dma_addr);
+
+	return err;
+}
+
+static int zynq_fpga_ops_write_complete(struct fpga_manager *mgr, u32 flags)
+{
+	struct zynq_fpga_priv *priv = mgr->priv;
+	int err;
+	u32 intr_status;
+
+	err = clk_enable(priv->clk);
+	if (err)
+		return err;
+
+	err = zynq_fpga_poll_timeout(priv, INT_STS_OFFSET, intr_status,
+				     intr_status & IXR_PCFG_DONE_MASK,
+				     INIT_POLL_DELAY,
+				     INIT_POLL_TIMEOUT);
+
+	clk_disable(priv->clk);
+
+	if (err)
+		return err;
+
+	/* for the partial reconfig case we didn't touch the level shifters */
+	if (!(flags & FPGA_MGR_PARTIAL_RECONFIG)) {
+		/* enable level shifters from PL to PS */
+		regmap_write(priv->slcr, SLCR_LVL_SHFTR_EN_OFFSET,
+			     LVL_SHFTR_ENABLE_PL_TO_PS);
+
+		/* deassert AXI interface resets */
+		regmap_write(priv->slcr, SLCR_FPGA_RST_CTRL_OFFSET,
+			     FPGA_RST_NONE_MASK);
+	}
+
+	return 0;
+}
+
+static enum fpga_mgr_states zynq_fpga_ops_state(struct fpga_manager *mgr)
+{
+	int err;
+	u32 intr_status;
+	struct zynq_fpga_priv *priv;
+
+	priv = mgr->priv;
+
+	err = clk_enable(priv->clk);
+	if (err)
+		return FPGA_MGR_STATE_UNKNOWN;
+
+	intr_status = zynq_fpga_read(priv, INT_STS_OFFSET);
+	clk_disable(priv->clk);
+
+	if (intr_status & IXR_PCFG_DONE_MASK)
+		return FPGA_MGR_STATE_OPERATING;
+
+	return FPGA_MGR_STATE_UNKNOWN;
+}
+
+static const struct fpga_manager_ops zynq_fpga_ops = {
+	.state = zynq_fpga_ops_state,
+	.write_init = zynq_fpga_ops_write_init,
+	.write = zynq_fpga_ops_write,
+	.write_complete = zynq_fpga_ops_write_complete,
+};
+
+static int zynq_fpga_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct zynq_fpga_priv *priv;
+	struct resource *res;
+	int err;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, priv);
+	priv->dev = dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->io_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(priv->io_base))
+		return PTR_ERR(priv->io_base);
+
+	priv->slcr = syscon_regmap_lookup_by_phandle(dev->of_node,
+		"syscon");
+	if (IS_ERR(priv->slcr)) {
+		dev_err(dev, "unable to get zynq-slcr regmap");
+		return PTR_ERR(priv->slcr);
+	}
+
+	init_completion(&priv->dma_done);
+
+	priv->irq = platform_get_irq(pdev, 0);
+	if (priv->irq < 0) {
+		dev_err(dev, "No IRQ available");
+		return priv->irq;
+	}
+
+	err = devm_request_irq(dev, priv->irq, zynq_fpga_isr, 0,
+			       dev_name(dev), priv);
+	if (err) {
+		dev_err(dev, "unable to request IRQ");
+		return err;
+	}
+
+	priv->clk = devm_clk_get(dev, "ref_clk");
+	if (IS_ERR(priv->clk)) {
+		dev_err(dev, "input clock not found");
+		return PTR_ERR(priv->clk);
+	}
+
+	err = clk_prepare_enable(priv->clk);
+	if (err) {
+		dev_err(dev, "unable to enable clock");
+		return err;
+	}
+
+	/* unlock the device */
+	zynq_fpga_write(priv, UNLOCK_OFFSET, UNLOCK_MASK);
+
+	clk_disable(priv->clk);
+
+	err = fpga_mgr_register(dev, "Xilinx Zynq FPGA Manager",
+				&zynq_fpga_ops, priv);
+	if (err) {
+		dev_err(dev, "unable to register FPGA manager");
+		clk_disable_unprepare(priv->clk);
+		return err;
+	}
+
+	return 0;
+}
+
+static int zynq_fpga_remove(struct platform_device *pdev)
+{
+	struct zynq_fpga_priv *priv;
+
+	fpga_mgr_unregister(&pdev->dev);
+
+	priv = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id zynq_fpga_of_match[] = {
+	{ .compatible = "xlnx,zynq-devcfg-1.0", },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, zynq_fpga_of_match);
+#endif
+
+static struct platform_driver zynq_fpga_driver = {
+	.probe = zynq_fpga_probe,
+	.remove = zynq_fpga_remove,
+	.driver = {
+		.name = "zynq_fpga_manager",
+		.of_match_table = of_match_ptr(zynq_fpga_of_match),
+	},
+};
+
+module_platform_driver(zynq_fpga_driver);
+
+MODULE_AUTHOR("Moritz Fischer <moritz.fischer@ettus.com>");
+MODULE_AUTHOR("Michal Simek <michal.simek@xilinx.com>");
+MODULE_DESCRIPTION("Xilinx Zynq FPGA Manager");
+MODULE_LICENSE("GPL v2");