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From:   jassisinghbrar@gmail.com
To:     dmaengine@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     vkoul@kernel.org, robh+dt@kernel.org, masami.hiramatsu@linaro.org,
        orito.takao@socionext.com, Jassi Brar <jaswinder.singh@linaro.org>
Subject: [PATCH v2 2/2] dmaengine: milbeaut-xdmac: Add XDMAC driver for Milbeaut platforms
Date:   Mon,  9 Sep 2019 20:45:50 -0500
Message-Id: <20190910014550.5695-1-jassisinghbrar@gmail.com>
In-Reply-To: <20190910014306.5318-1-jassisinghbrar@gmail.com>
References: <20190910014306.5318-1-jassisinghbrar@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Jassi Brar <jaswinder.singh@linaro.org>

Driver for Socionext Milbeaut XDMAC controller. The controller only
supports Mem-To-Mem transfers over upto 8 configurable channels.

Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
---
 drivers/dma/Kconfig          |  10 +
 drivers/dma/Makefile         |   1 +
 drivers/dma/milbeaut-xdmac.c | 426 +++++++++++++++++++++++++++++++++++
 3 files changed, 437 insertions(+)
 create mode 100644 drivers/dma/milbeaut-xdmac.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 66979f27f0f3..e0e3b21a0c4c 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -358,6 +358,16 @@ config MILBEAUT_HDMAC
 	  Say yes here to support the Socionext Milbeaut
 	  HDMAC device.
 
+config MILBEAUT_XDMAC
+	tristate "Milbeaut AXI DMA support"
+	depends on ARCH_MILBEAUT || COMPILE_TEST
+	depends on OF
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Say yes here to support the Socionext Milbeaut
+	  XDMAC device.
+
 config MMP_PDMA
 	bool "MMP PDMA support"
 	depends on ARCH_MMP || ARCH_PXA || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index e4aed0730dea..41e06a845b01 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -47,6 +47,7 @@ obj-$(CONFIG_INTEL_MIC_X100_DMA) += mic_x100_dma.o
 obj-$(CONFIG_K3_DMA) += k3dma.o
 obj-$(CONFIG_LPC18XX_DMAMUX) += lpc18xx-dmamux.o
 obj-$(CONFIG_MILBEAUT_HDMAC) += milbeaut-hdmac.o
+obj-$(CONFIG_MILBEAUT_XDMAC) += milbeaut-xdmac.o
 obj-$(CONFIG_MMP_PDMA) += mmp_pdma.o
 obj-$(CONFIG_MMP_TDMA) += mmp_tdma.o
 obj-$(CONFIG_MOXART_DMA) += moxart-dma.o
diff --git a/drivers/dma/milbeaut-xdmac.c b/drivers/dma/milbeaut-xdmac.c
new file mode 100644
index 000000000000..f2e04541d031
--- /dev/null
+++ b/drivers/dma/milbeaut-xdmac.c
@@ -0,0 +1,426 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (C) 2019 Linaro Ltd.
+// Copyright (C) 2019 Socionext Inc.
+
+#include <linux/bits.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+#include <linux/iopoll.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/bitfield.h>
+
+#include "virt-dma.h"
+
+/* global register */
+#define M10V_XDACS 0x00
+
+/* channel local register */
+#define M10V_XDTBC 0x10
+#define M10V_XDSSA 0x14
+#define M10V_XDDSA 0x18
+#define M10V_XDSAC 0x1C
+#define M10V_XDDAC 0x20
+#define M10V_XDDCC 0x24
+#define M10V_XDDES 0x28
+#define M10V_XDDPC 0x2C
+#define M10V_XDDSD 0x30
+
+#define M10V_XDACS_XE BIT(28)
+
+#define M10V_DEFBS	0x3
+#define M10V_DEFBL	0xf
+
+#define M10V_XDSAC_SBS	GENMASK(17, 16)
+#define M10V_XDSAC_SBL	GENMASK(11, 8)
+
+#define M10V_XDDAC_DBS	GENMASK(17, 16)
+#define M10V_XDDAC_DBL	GENMASK(11, 8)
+
+#define M10V_XDDES_CE	BIT(28)
+#define M10V_XDDES_SE	BIT(24)
+#define M10V_XDDES_SA	BIT(15)
+#define M10V_XDDES_TF	GENMASK(23, 20)
+#define M10V_XDDES_EI	BIT(1)
+#define M10V_XDDES_TI	BIT(0)
+
+#define M10V_XDDSD_IS_MASK	GENMASK(3, 0)
+#define M10V_XDDSD_IS_NORMAL	0x8
+
+#define MLB_XDMAC_BUSWIDTHS	(BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
+				 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
+				 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
+				 BIT(DMA_SLAVE_BUSWIDTH_8_BYTES))
+
+struct milbeaut_xdmac_desc {
+	struct virt_dma_desc vd;
+	size_t len;
+	dma_addr_t src;
+	dma_addr_t dst;
+};
+
+struct milbeaut_xdmac_chan {
+	struct virt_dma_chan vc;
+	struct milbeaut_xdmac_device *mdev;
+	struct milbeaut_xdmac_desc *md;
+	void __iomem *reg_ch_base;
+	int irq;
+	struct dma_slave_config	cfg;
+};
+
+struct milbeaut_xdmac_device {
+	struct dma_device ddev;
+	void __iomem *reg_base;
+	struct milbeaut_xdmac_chan channels[0];
+};
+
+static struct milbeaut_xdmac_chan *
+to_milbeaut_xdmac_chan(struct virt_dma_chan *vc)
+{
+	return container_of(vc, struct milbeaut_xdmac_chan, vc);
+}
+
+static struct milbeaut_xdmac_desc *
+to_milbeaut_xdmac_desc(struct virt_dma_desc *vd)
+{
+	return container_of(vd, struct milbeaut_xdmac_desc, vd);
+}
+
+/* mc->vc.lock must be held by caller */
+static struct milbeaut_xdmac_desc *
+milbeaut_xdmac_next_desc(struct milbeaut_xdmac_chan *mc)
+{
+	struct virt_dma_desc *vd;
+
+	vd = vchan_next_desc(&mc->vc);
+	if (!vd) {
+		mc->md = NULL;
+		return NULL;
+	}
+
+	list_del(&vd->node);
+
+	mc->md = to_milbeaut_xdmac_desc(vd);
+
+	return mc->md;
+}
+
+/* mc->vc.lock must be held by caller */
+static void milbeaut_chan_start(struct milbeaut_xdmac_chan *mc,
+				struct milbeaut_xdmac_desc *md)
+{
+	u32 val;
+
+	/* Setup the channel */
+	val = md->len - 1;
+	writel_relaxed(val, mc->reg_ch_base + M10V_XDTBC);
+
+	val = md->src;
+	writel_relaxed(val, mc->reg_ch_base + M10V_XDSSA);
+
+	val = md->dst;
+	writel_relaxed(val, mc->reg_ch_base + M10V_XDDSA);
+
+	val = readl_relaxed(mc->reg_ch_base + M10V_XDSAC);
+	val &= ~(M10V_XDSAC_SBS | M10V_XDSAC_SBL);
+	val |= FIELD_PREP(M10V_XDSAC_SBS, M10V_DEFBS) |
+		FIELD_PREP(M10V_XDSAC_SBL, M10V_DEFBL);
+	writel_relaxed(val, mc->reg_ch_base + M10V_XDSAC);
+
+	val = readl_relaxed(mc->reg_ch_base + M10V_XDDAC);
+	val &= ~(M10V_XDDAC_DBS | M10V_XDDAC_DBL);
+	val |= FIELD_PREP(M10V_XDDAC_DBS, M10V_DEFBS) |
+		FIELD_PREP(M10V_XDDAC_DBL, M10V_DEFBL);
+	writel_relaxed(val, mc->reg_ch_base + M10V_XDDAC);
+
+	/* Start the channel */
+	val = readl_relaxed(mc->reg_ch_base + M10V_XDDES);
+	val &= ~(M10V_XDDES_CE | M10V_XDDES_SE | M10V_XDDES_TF |
+		 M10V_XDDES_EI | M10V_XDDES_TI);
+	val |= FIELD_PREP(M10V_XDDES_CE, 1) | FIELD_PREP(M10V_XDDES_SE, 1) |
+		FIELD_PREP(M10V_XDDES_TF, 1) | FIELD_PREP(M10V_XDDES_EI, 1) |
+		FIELD_PREP(M10V_XDDES_TI, 1);
+	writel_relaxed(val, mc->reg_ch_base + M10V_XDDES);
+}
+
+/* mc->vc.lock must be held by caller */
+static void milbeaut_xdmac_start(struct milbeaut_xdmac_chan *mc)
+{
+	struct milbeaut_xdmac_desc *md;
+
+	md = milbeaut_xdmac_next_desc(mc);
+	if (md)
+		milbeaut_chan_start(mc, md);
+}
+
+static irqreturn_t milbeaut_xdmac_interrupt(int irq, void *dev_id)
+{
+	struct milbeaut_xdmac_chan *mc = dev_id;
+	struct milbeaut_xdmac_desc *md;
+	irqreturn_t ret = IRQ_HANDLED;
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&mc->vc.lock, flags);
+
+	/* Ack and Stop */
+	val = FIELD_PREP(M10V_XDDSD_IS_MASK, 0x0);
+	writel_relaxed(val, mc->reg_ch_base + M10V_XDDSD);
+
+	md = mc->md;
+	if (!md)
+		goto out;
+
+	vchan_cookie_complete(&md->vd);
+
+	milbeaut_xdmac_start(mc);
+out:
+	spin_unlock_irqrestore(&mc->vc.lock, flags);
+	return ret;
+}
+
+static void milbeaut_xdmac_free_chan_resources(struct dma_chan *chan)
+{
+	vchan_free_chan_resources(to_virt_chan(chan));
+}
+
+static struct dma_async_tx_descriptor *
+milbeaut_xdmac_prep_memcpy(struct dma_chan *chan, dma_addr_t dst,
+			   dma_addr_t src, size_t len, unsigned long flags)
+{
+	struct virt_dma_chan *vc = to_virt_chan(chan);
+	struct milbeaut_xdmac_desc *md;
+
+	md = kzalloc(sizeof(*md), GFP_NOWAIT);
+	if (!md)
+		return NULL;
+
+	md->len = len;
+	md->src = src;
+	md->dst = dst;
+
+	return vchan_tx_prep(vc, &md->vd, flags);
+}
+
+static int milbeaut_xdmac_terminate_all(struct dma_chan *chan)
+{
+	struct virt_dma_chan *vc = to_virt_chan(chan);
+	struct milbeaut_xdmac_chan *mc = to_milbeaut_xdmac_chan(vc);
+	unsigned long flags;
+	int ret = 0;
+	u32 val;
+
+	LIST_HEAD(head);
+
+	spin_lock_irqsave(&vc->lock, flags);
+
+	/* Halt the channel */
+	val = readl(mc->reg_ch_base + M10V_XDDES);
+	val &= ~M10V_XDDES_CE;
+	val |= FIELD_PREP(M10V_XDDES_CE, 0);
+	writel(val, mc->reg_ch_base + M10V_XDDES);
+
+	if (mc->md) {
+		vchan_terminate_vdesc(&mc->md->vd);
+		mc->md = NULL;
+	}
+
+	vchan_get_all_descriptors(vc, &head);
+
+	spin_unlock_irqrestore(&vc->lock, flags);
+
+	vchan_dma_desc_free_list(vc, &head);
+
+	return ret;
+}
+
+static void milbeaut_xdmac_synchronize(struct dma_chan *chan)
+{
+	vchan_synchronize(to_virt_chan(chan));
+}
+
+static void milbeaut_xdmac_issue_pending(struct dma_chan *chan)
+{
+	struct virt_dma_chan *vc = to_virt_chan(chan);
+	struct milbeaut_xdmac_chan *mc = to_milbeaut_xdmac_chan(vc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&vc->lock, flags);
+
+	if (vchan_issue_pending(vc) && !mc->md)
+		milbeaut_xdmac_start(mc);
+
+	spin_unlock_irqrestore(&vc->lock, flags);
+}
+
+static void milbeaut_xdmac_desc_free(struct virt_dma_desc *vd)
+{
+	kfree(to_milbeaut_xdmac_desc(vd));
+}
+
+static int milbeaut_xdmac_chan_init(struct platform_device *pdev,
+				    struct milbeaut_xdmac_device *mdev,
+				    int chan_id)
+{
+	struct device *dev = &pdev->dev;
+	struct milbeaut_xdmac_chan *mc = &mdev->channels[chan_id];
+	char *irq_name;
+	int irq, ret;
+
+	irq = platform_get_irq(pdev, chan_id);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "failed to get IRQ number for ch%d\n",
+			chan_id);
+		return irq;
+	}
+
+	irq_name = devm_kasprintf(dev, GFP_KERNEL, "milbeaut-xdmac-%d",
+				  chan_id);
+	if (!irq_name)
+		return -ENOMEM;
+
+	ret = devm_request_irq(dev, irq, milbeaut_xdmac_interrupt,
+			       IRQF_SHARED, irq_name, mc);
+	if (ret)
+		return ret;
+
+	mc->mdev = mdev;
+	mc->reg_ch_base = mdev->reg_base + chan_id * 0x30;
+
+	mc->vc.desc_free = milbeaut_xdmac_desc_free;
+	vchan_init(&mc->vc, &mdev->ddev);
+
+	return 0;
+}
+
+static void enable_xdmac(struct milbeaut_xdmac_device *mdev)
+{
+	unsigned int val;
+
+	val = readl(mdev->reg_base + M10V_XDACS);
+	val |= M10V_XDACS_XE;
+	writel(val, mdev->reg_base + M10V_XDACS);
+}
+
+static void disable_xdmac(struct milbeaut_xdmac_device *mdev)
+{
+	unsigned int val;
+
+	val = readl(mdev->reg_base + M10V_XDACS);
+	val &= ~M10V_XDACS_XE;
+	writel(val, mdev->reg_base + M10V_XDACS);
+}
+
+static int milbeaut_xdmac_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct milbeaut_xdmac_device *mdev;
+	struct dma_device *ddev;
+	struct resource *res;
+	int nr_chans, ret, i;
+
+	nr_chans = platform_irq_count(pdev);
+	if (nr_chans < 0)
+		return nr_chans;
+
+	mdev = devm_kzalloc(dev, struct_size(mdev, channels, nr_chans),
+			    GFP_KERNEL);
+	if (!mdev)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mdev->reg_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(mdev->reg_base))
+		return PTR_ERR(mdev->reg_base);
+
+	ddev = &mdev->ddev;
+	ddev->dev = dev;
+	dma_cap_set(DMA_MEMCPY, ddev->cap_mask);
+	ddev->src_addr_widths = MLB_XDMAC_BUSWIDTHS;
+	ddev->dst_addr_widths = MLB_XDMAC_BUSWIDTHS;
+	ddev->device_free_chan_resources = milbeaut_xdmac_free_chan_resources;
+	ddev->device_prep_dma_memcpy = milbeaut_xdmac_prep_memcpy;
+	ddev->device_terminate_all = milbeaut_xdmac_terminate_all;
+	ddev->device_synchronize = milbeaut_xdmac_synchronize;
+	ddev->device_tx_status = dma_cookie_status;
+	ddev->device_issue_pending = milbeaut_xdmac_issue_pending;
+	INIT_LIST_HEAD(&ddev->channels);
+
+	for (i = 0; i < nr_chans; i++) {
+		ret = milbeaut_xdmac_chan_init(pdev, mdev, i);
+		if (ret)
+			return ret;
+	}
+
+	enable_xdmac(mdev);
+
+	ret = dma_async_device_register(ddev);
+	if (ret)
+		return ret;
+
+	ret = of_dma_controller_register(dev->of_node,
+					 of_dma_simple_xlate, mdev);
+	if (ret)
+		goto unregister_dmac;
+
+	platform_set_drvdata(pdev, mdev);
+
+	return 0;
+
+unregister_dmac:
+	dma_async_device_unregister(ddev);
+	return ret;
+}
+
+static int milbeaut_xdmac_remove(struct platform_device *pdev)
+{
+	struct milbeaut_xdmac_device *mdev = platform_get_drvdata(pdev);
+	struct dma_chan *chan;
+	int ret;
+
+	/*
+	 * Before reaching here, almost all descriptors have been freed by the
+	 * ->device_free_chan_resources() hook. However, each channel might
+	 * be still holding one descriptor that was on-flight at that moment.
+	 * Terminate it to make sure this hardware is no longer running. Then,
+	 * free the channel resources once again to avoid memory leak.
+	 */
+	list_for_each_entry(chan, &mdev->ddev.channels, device_node) {
+		ret = dmaengine_terminate_sync(chan);
+		if (ret)
+			return ret;
+		milbeaut_xdmac_free_chan_resources(chan);
+	}
+
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&mdev->ddev);
+
+	disable_xdmac(mdev);
+
+	return 0;
+}
+
+static const struct of_device_id milbeaut_xdmac_match[] = {
+	{ .compatible = "socionext,milbeaut-m10v-xdmac" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, milbeaut_xdmac_match);
+
+static struct platform_driver milbeaut_xdmac_driver = {
+	.probe = milbeaut_xdmac_probe,
+	.remove = milbeaut_xdmac_remove,
+	.driver = {
+		.name = "milbeaut-m10v-xdmac",
+		.of_match_table = milbeaut_xdmac_match,
+	},
+};
+module_platform_driver(milbeaut_xdmac_driver);
+
+MODULE_DESCRIPTION("Milbeaut XDMAC DmaEngine driver");
+MODULE_LICENSE("GPL v2");
-- 
2.17.1