[PATCH v4 1/2] powerpc/512x: add LocalPlus Bus FIFO device driver

[Alexander Popov]

This driver for Freescale MPC512x LocalPlus Bus FIFO (called SCLPC
in the Reference Manual) allows Direct Memory Access transfers
between RAM and peripheral devices on LocalPlus Bus.

Signed-off-by: Alexander Popov <alex.popov@xxxxxxxxx>
---
 arch/powerpc/configs/mpc512x_defconfig        |   1 +
 arch/powerpc/include/asm/mpc5121.h            |  59 +++
 arch/powerpc/platforms/512x/Kconfig           |   6 +
 arch/powerpc/platforms/512x/Makefile          |   1 +
 arch/powerpc/platforms/512x/mpc512x_lpbfifo.c | 539 ++++++++++++++++++++++++++
 5 files changed, 606 insertions(+)
 create mode 100644 arch/powerpc/platforms/512x/mpc512x_lpbfifo.c

diff --git a/arch/powerpc/configs/mpc512x_defconfig b/arch/powerpc/configs/mpc512x_defconfig
index 59b85cb..d16d6c5 100644
--- a/arch/powerpc/configs/mpc512x_defconfig
+++ b/arch/powerpc/configs/mpc512x_defconfig
@@ -112,6 +112,7 @@ CONFIG_RTC_DRV_M41T80=y
 CONFIG_RTC_DRV_MPC5121=y
 CONFIG_DMADEVICES=y
 CONFIG_MPC512X_DMA=y
+CONFIG_MPC512x_LPBFIFO=y
 CONFIG_EXT2_FS=y
 CONFIG_EXT2_FS_XIP=y
 CONFIG_EXT3_FS=y
diff --git a/arch/powerpc/include/asm/mpc5121.h b/arch/powerpc/include/asm/mpc5121.h
index 4a69cd1..deaeb0b 100644
--- a/arch/powerpc/include/asm/mpc5121.h
+++ b/arch/powerpc/include/asm/mpc5121.h
@@ -60,4 +60,63 @@ struct mpc512x_lpc {
 
 int mpc512x_cs_config(unsigned int cs, u32 val);
 
+/*
+ * SCLPC Module (LPB FIFO)
+ */
+struct mpc512x_lpbfifo {
+	u32	pkt_size;	/* SCLPC Packet Size Register */
+	u32	start_addr;	/* SCLPC Start Address Register */
+	u32	ctrl;		/* SCLPC Control Register */
+	u32	enable;		/* SCLPC Enable Register */
+	u32	reserved1;
+	u32	status;		/* SCLPC Status Register */
+	u32	bytes_done;	/* SCLPC Bytes Done Register */
+	u32	emb_sc;		/* EMB Share Counter Register */
+	u32	emb_pc;		/* EMB Pause Control Register */
+	u32	reserved2[7];
+	u32	data_word;	/* LPC RX/TX FIFO Data Word Register */
+	u32	fifo_status;	/* LPC RX/TX FIFO Status Register */
+	u32	fifo_ctrl;	/* LPC RX/TX FIFO Control Register */
+	u32	fifo_alarm;	/* LPC RX/TX FIFO Alarm Register */
+};
+
+#define MPC512X_SCLPC_START		(1 << 31)
+#define MPC512X_SCLPC_CS(x)		(((x) & 0x7) << 24)
+#define MPC512X_SCLPC_FLUSH		(1 << 17)
+#define MPC512X_SCLPC_READ		(1 << 16)
+#define MPC512X_SCLPC_DAI		(1 << 8)
+#define MPC512X_SCLPC_BPT(x)		((x) & 0x3f)
+#define MPC512X_SCLPC_RESET		(1 << 24)
+#define MPC512X_SCLPC_FIFO_RESET	(1 << 16)
+#define MPC512X_SCLPC_ABORT_INT_ENABLE	(1 << 9)
+#define MPC512X_SCLPC_NORM_INT_ENABLE	(1 << 8)
+#define MPC512X_SCLPC_ENABLE		(1 << 0)
+#define MPC512X_SCLPC_SUCCESS		(1 << 24)
+#define MPC512X_SCLPC_FIFO_CTRL(x)	(((x) & 0x7) << 24)
+#define MPC512X_SCLPC_FIFO_ALARM(x)	((x) & 0x3ff)
+
+enum lpb_dev_portsize {
+	LPB_DEV_PORTSIZE_UNDEFINED = 0,
+	LPB_DEV_PORTSIZE_1_BYTE = 1,
+	LPB_DEV_PORTSIZE_2_BYTES = 2,
+	LPB_DEV_PORTSIZE_4_BYTES = 4,
+	LPB_DEV_PORTSIZE_8_BYTES = 8
+};
+
+enum mpc512x_lpbfifo_req_dir {
+	MPC512X_LPBFIFO_REQ_DIR_READ,
+	MPC512X_LPBFIFO_REQ_DIR_WRITE
+};
+
+struct mpc512x_lpbfifo_request {
+	phys_addr_t dev_phys_addr; /* physical address of some device on LPB */
+	void *ram_virt_addr; /* virtual address of some region in RAM */
+	u32 size;
+	enum lpb_dev_portsize portsize;
+	enum mpc512x_lpbfifo_req_dir dir;
+	void (*callback)(struct mpc512x_lpbfifo_request *);
+};
+
+int mpc512x_lpbfifo_submit(struct mpc512x_lpbfifo_request *req);
+
 #endif /* __ASM_POWERPC_MPC5121_H__ */
diff --git a/arch/powerpc/platforms/512x/Kconfig b/arch/powerpc/platforms/512x/Kconfig
index 48bf38d..f09016f 100644
--- a/arch/powerpc/platforms/512x/Kconfig
+++ b/arch/powerpc/platforms/512x/Kconfig
@@ -10,6 +10,12 @@ config PPC_MPC512x
 	select USB_EHCI_BIG_ENDIAN_MMIO if USB_EHCI_HCD
 	select USB_EHCI_BIG_ENDIAN_DESC if USB_EHCI_HCD
 
+config MPC512x_LPBFIFO
+	tristate "MPC512x LocalPlus Bus FIFO driver"
+	depends on PPC_MPC512x && MPC512X_DMA
+	help
+	  Enable support for Freescale MPC512x LocalPlus Bus FIFO (SCLPC).
+
 config MPC5121_ADS
 	bool "Freescale MPC5121E ADS"
 	depends on PPC_MPC512x
diff --git a/arch/powerpc/platforms/512x/Makefile b/arch/powerpc/platforms/512x/Makefile
index 0169312..f47d422 100644
--- a/arch/powerpc/platforms/512x/Makefile
+++ b/arch/powerpc/platforms/512x/Makefile
@@ -5,4 +5,5 @@ obj-$(CONFIG_COMMON_CLK)	+= clock-commonclk.o
 obj-y				+= mpc512x_shared.o
 obj-$(CONFIG_MPC5121_ADS)	+= mpc5121_ads.o mpc5121_ads_cpld.o
 obj-$(CONFIG_MPC512x_GENERIC)	+= mpc512x_generic.o
+obj-$(CONFIG_MPC512x_LPBFIFO)	+= mpc512x_lpbfifo.o
 obj-$(CONFIG_PDM360NG)		+= pdm360ng.o
diff --git a/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c b/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c
new file mode 100644
index 0000000..2ddb395
--- /dev/null
+++ b/arch/powerpc/platforms/512x/mpc512x_lpbfifo.c
@@ -0,0 +1,539 @@
+/*
+ * The driver for Freescale MPC512x LocalPlus Bus FIFO
+ * (called SCLPC in the Reference Manual).
+ *
+ * Copyright (C) 2013-2015 Alexander Popov <alex.popov@xxxxxxxxx>.
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <asm/mpc5121.h>
+#include <asm/io.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-direction.h>
+#include <linux/dma-mapping.h>
+
+#define DRV_NAME "mpc512x_lpbfifo"
+
+struct cs_range {
+	u32 csnum;
+	u32 base; /* must be zero */
+	u32 addr;
+	u32 size;
+};
+
+static struct lpbfifo_data {
+	spinlock_t lock; /* for protecting lpbfifo_data */
+	phys_addr_t regs_phys;
+	resource_size_t regs_size;
+	struct mpc512x_lpbfifo __iomem *regs;
+	int irq;
+	struct cs_range *cs_ranges;
+	size_t cs_n;
+	struct dma_chan *chan;
+	struct mpc512x_lpbfifo_request *req;
+	dma_addr_t ram_bus_addr;
+	bool wait_lpbfifo_irq;
+	bool wait_lpbfifo_callback;
+} lpbfifo;
+
+/*
+ * A data transfer from RAM to some device on LPB is finished
+ * when both mpc512x_lpbfifo_irq() and mpc512x_lpbfifo_callback()
+ * have been called. We execute the callback registered in
+ * mpc512x_lpbfifo_request just after that.
+ * But for a data transfer from some device on LPB to RAM we don't enable
+ * LPBFIFO interrupt because clearing MPC512X_SCLPC_SUCCESS interrupt flag
+ * automatically disables LPBFIFO reading request to the DMA controller
+ * and the data transfer hangs. So the callback registered in
+ * mpc512x_lpbfifo_request is executed at the end of mpc512x_lpbfifo_callback().
+ */
+
+/*
+ * mpc512x_lpbfifo_irq - IRQ handler for LPB FIFO
+ */
+static irqreturn_t mpc512x_lpbfifo_irq(int irq, void *param)
+{
+	struct device *dev = (struct device *)param;
+	struct mpc512x_lpbfifo_request *req = NULL;
+	unsigned long flags;
+	u32 status;
+
+	spin_lock_irqsave(&lpbfifo.lock, flags);
+
+	if (!lpbfifo.regs)
+		goto end;
+
+	req = lpbfifo.req;
+	if (!req || req->dir == MPC512X_LPBFIFO_REQ_DIR_READ) {
+		dev_err(dev, "bogus LPBFIFO IRQ\n");
+		goto end;
+	}
+
+	status = in_be32(&lpbfifo.regs->status);
+	if (status != MPC512X_SCLPC_SUCCESS) {
+		dev_err(dev, "DMA transfer from RAM to peripheral failed\n");
+		out_be32(&lpbfifo.regs->enable,
+				MPC512X_SCLPC_RESET | MPC512X_SCLPC_FIFO_RESET);
+		goto end;
+	}
+	/* Clear the interrupt flag */
+	out_be32(&lpbfifo.regs->status, MPC512X_SCLPC_SUCCESS);
+
+	lpbfifo.wait_lpbfifo_irq = false;
+
+	if (lpbfifo.wait_lpbfifo_callback)
+		goto end;
+
+	/* Transfer is finished, set the FIFO as idle */
+	lpbfifo.req = NULL;
+
+	spin_unlock_irqrestore(&lpbfifo.lock, flags);
+
+	if (req->callback)
+		req->callback(req);
+
+	return IRQ_HANDLED;
+
+ end:
+	spin_unlock_irqrestore(&lpbfifo.lock, flags);
+	return IRQ_HANDLED;
+}
+
+/*
+ * mpc512x_lpbfifo_callback is called by DMA driver when
+ * DMA transaction is finished.
+ */
+static void mpc512x_lpbfifo_callback(void *param)
+{
+	unsigned long flags;
+	struct mpc512x_lpbfifo_request *req = NULL;
+	enum dma_data_direction dir;
+
+	spin_lock_irqsave(&lpbfifo.lock, flags);
+
+	if (!lpbfifo.regs) {
+		spin_unlock_irqrestore(&lpbfifo.lock, flags);
+		return;
+	}
+
+	req = lpbfifo.req;
+	if (!req) {
+		pr_err("bogus LPBFIFO callback\n");
+		spin_unlock_irqrestore(&lpbfifo.lock, flags);
+		return;
+	}
+
+	/* Release the mapping */
+	if (req->dir == MPC512X_LPBFIFO_REQ_DIR_WRITE)
+		dir = DMA_TO_DEVICE;
+	else
+		dir = DMA_FROM_DEVICE;
+	dma_unmap_single(lpbfifo.chan->device->dev,
+			lpbfifo.ram_bus_addr, req->size, dir);
+
+	lpbfifo.wait_lpbfifo_callback = false;
+
+	if (!lpbfifo.wait_lpbfifo_irq) {
+		/* Transfer is finished, set the FIFO as idle */
+		lpbfifo.req = NULL;
+
+		spin_unlock_irqrestore(&lpbfifo.lock, flags);
+
+		if (req->callback)
+			req->callback(req);
+	} else {
+		spin_unlock_irqrestore(&lpbfifo.lock, flags);
+	}
+}
+
+static int mpc512x_lpbfifo_kick(void)
+{
+	u32 bits;
+	bool no_incr = false;
+	u32 bpt = 32; /* max bytes per LPBFIFO transaction involving DMA */
+	u32 cs = 0;
+	size_t i;
+	struct dma_device *dma_dev = NULL;
+	struct scatterlist sg;
+	enum dma_data_direction dir;
+	struct dma_slave_config dma_conf = {};
+	struct dma_async_tx_descriptor *dma_tx = NULL;
+	dma_cookie_t cookie;
+	int ret;
+
+	/*
+	 * 1. Fit the requirements:
+	 * - the packet size must be a multiple of 4 since FIFO Data Word
+	 *    Register allows only full-word access according the Reference
+	 *    Manual;
+	 * - the physical address of the device on LPB and the packet size
+	 *    must be aligned on BPT (bytes per transaction) or 8-bytes
+	 *    boundary according the Reference Manual;
+	 * - but we choose DMA maxburst equal (or very close to) BPT to prevent
+	 *    DMA controller from overtaking FIFO and causing FIFO underflow
+	 *    error. So we force the packet size to be aligned on BPT boundary
+	 *    not to confuse DMA driver which requires the packet size to be
+	 *    aligned on maxburst boundary;
+	 * - BPT should be set to the LPB device port size for operation with
+	 *    disabled auto-incrementing according Reference Manual.
+	 */
+	if (lpbfifo.req->size == 0 || !IS_ALIGNED(lpbfifo.req->size, 4))
+		return -EINVAL;
+
+	if (lpbfifo.req->portsize != LPB_DEV_PORTSIZE_UNDEFINED) {
+		bpt = lpbfifo.req->portsize;
+		no_incr = true;
+	}
+
+	while (bpt > 1) {
+		if (IS_ALIGNED(lpbfifo.req->dev_phys_addr, min(bpt, 0x8u)) &&
+					IS_ALIGNED(lpbfifo.req->size, bpt)) {
+			break;
+		}
+
+		if (no_incr)
+			return -EINVAL;
+
+		bpt >>= 1;
+	}
+	dma_conf.dst_maxburst = max(bpt, 0x4u) / 4;
+	dma_conf.src_maxburst = max(bpt, 0x4u) / 4;
+
+	for (i = 0; i < lpbfifo.cs_n; i++) {
+		phys_addr_t cs_start = lpbfifo.cs_ranges[i].addr;
+		phys_addr_t cs_end = cs_start + lpbfifo.cs_ranges[i].size;
+		phys_addr_t access_start = lpbfifo.req->dev_phys_addr;
+		phys_addr_t access_end = access_start + lpbfifo.req->size;
+
+		if (access_start >= cs_start && access_end <= cs_end) {
+			cs = lpbfifo.cs_ranges[i].csnum;
+			break;
+		}
+	}
+	if (i == lpbfifo.cs_n)
+		return -EFAULT;
+
+	/* 2. Prepare DMA */
+	dma_dev = lpbfifo.chan->device;
+
+	if (lpbfifo.req->dir == MPC512X_LPBFIFO_REQ_DIR_WRITE) {
+		dir = DMA_TO_DEVICE;
+		dma_conf.direction = DMA_MEM_TO_DEV;
+		dma_conf.dst_addr = lpbfifo.regs_phys +
+				offsetof(struct mpc512x_lpbfifo, data_word);
+	} else {
+		dir = DMA_FROM_DEVICE;
+		dma_conf.direction = DMA_DEV_TO_MEM;
+		dma_conf.src_addr = lpbfifo.regs_phys +
+				offsetof(struct mpc512x_lpbfifo, data_word);
+	}
+	dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+
+	/* Make DMA channel work with LPB FIFO data register */
+	if (dma_dev->device_config(lpbfifo.chan, &dma_conf)) {
+		ret = -EINVAL;
+		goto err_dma_prep;
+	}
+
+	sg_init_table(&sg, 1);
+
+	sg_dma_address(&sg) = dma_map_single(dma_dev->dev,
+			lpbfifo.req->ram_virt_addr, lpbfifo.req->size, dir);
+	if (dma_mapping_error(dma_dev->dev, sg_dma_address(&sg)))
+		return -EFAULT;
+
+	lpbfifo.ram_bus_addr = sg_dma_address(&sg); /* For freeing later */
+
+	sg_dma_len(&sg) = lpbfifo.req->size;
+
+	dma_tx = dmaengine_prep_slave_sg(lpbfifo.chan, &sg,
+						1, dma_conf.direction, 0);
+	if (!dma_tx) {
+		ret = -ENOSPC;
+		goto err_dma_prep;
+	}
+	dma_tx->callback = mpc512x_lpbfifo_callback;
+	dma_tx->callback_param = NULL;
+
+	/* 3. Prepare FIFO */
+	out_be32(&lpbfifo.regs->enable,
+				MPC512X_SCLPC_RESET | MPC512X_SCLPC_FIFO_RESET);
+	out_be32(&lpbfifo.regs->enable, 0x0);
+
+	/*
+	 * Configure the watermarks for write operation (RAM->DMA->FIFO->dev):
+	 * - high watermark 7 words according the Reference Manual,
+	 * - low watermark 512 bytes (half of the FIFO).
+	 * These watermarks don't work for read operation since the
+	 * MPC512X_SCLPC_FLUSH bit is set (according the Reference Manual).
+	 */
+	out_be32(&lpbfifo.regs->fifo_ctrl, MPC512X_SCLPC_FIFO_CTRL(0x7));
+	out_be32(&lpbfifo.regs->fifo_alarm, MPC512X_SCLPC_FIFO_ALARM(0x200));
+
+	/*
+	 * Start address is a physical address of the region which belongs
+	 * to the device on the LocalPlus Bus
+	 */
+	out_be32(&lpbfifo.regs->start_addr, lpbfifo.req->dev_phys_addr);
+
+	/*
+	 * Configure chip select, transfer direction, address increment option
+	 * and bytes per transaction option
+	 */
+	bits = MPC512X_SCLPC_CS(cs);
+	if (lpbfifo.req->dir == MPC512X_LPBFIFO_REQ_DIR_READ)
+		bits |= MPC512X_SCLPC_READ | MPC512X_SCLPC_FLUSH;
+	if (no_incr)
+		bits |= MPC512X_SCLPC_DAI;
+	bits |= MPC512X_SCLPC_BPT(bpt);
+	out_be32(&lpbfifo.regs->ctrl, bits);
+
+	/* Unmask irqs */
+	bits = MPC512X_SCLPC_ENABLE | MPC512X_SCLPC_ABORT_INT_ENABLE;
+	if (lpbfifo.req->dir == MPC512X_LPBFIFO_REQ_DIR_WRITE)
+		bits |= MPC512X_SCLPC_NORM_INT_ENABLE;
+	else
+		lpbfifo.wait_lpbfifo_irq = false;
+
+	out_be32(&lpbfifo.regs->enable, bits);
+
+	/* 4. Set packet size and kick FIFO off */
+	bits = lpbfifo.req->size | MPC512X_SCLPC_START;
+	out_be32(&lpbfifo.regs->pkt_size, bits);
+
+	/* 5. Finally kick DMA off */
+	cookie = dma_tx->tx_submit(dma_tx);
+	if (dma_submit_error(cookie)) {
+		ret = -ENOSPC;
+		goto err_dma_submit;
+	}
+
+	return 0;
+
+ err_dma_submit:
+	out_be32(&lpbfifo.regs->enable,
+				MPC512X_SCLPC_RESET | MPC512X_SCLPC_FIFO_RESET);
+ err_dma_prep:
+	dma_unmap_single(dma_dev->dev, sg_dma_address(&sg),
+						lpbfifo.req->size, dir);
+	return ret;
+}
+
+static int mpc512x_lpbfifo_submit_locked(struct mpc512x_lpbfifo_request *req)
+{
+	int ret = 0;
+
+	if (!lpbfifo.regs)
+		return -ENODEV;
+
+	/* Check whether a transfer is in progress */
+	if (lpbfifo.req)
+		return -EBUSY;
+
+	lpbfifo.wait_lpbfifo_irq = true;
+	lpbfifo.wait_lpbfifo_callback = true;
+	lpbfifo.req = req;
+
+	ret = mpc512x_lpbfifo_kick();
+	if (ret != 0)
+		lpbfifo.req = NULL; /* Set the FIFO as idle */
+
+	return ret;
+}
+
+int mpc512x_lpbfifo_submit(struct mpc512x_lpbfifo_request *req)
+{
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&lpbfifo.lock, flags);
+	ret = mpc512x_lpbfifo_submit_locked(req);
+	spin_unlock_irqrestore(&lpbfifo.lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(mpc512x_lpbfifo_submit);
+
+/*
+ * LPBFIFO driver uses "ranges" property of "localbus" device tree node
+ * for being able to determine the chip select number of a client device
+ * ordering a DMA transfer.
+ */
+static int get_cs_ranges(struct device *dev)
+{
+	int ret = -ENODEV;
+	struct device_node *lb_node;
+	const u32 *addr_cells_p;
+	const u32 *size_cells_p;
+	int proplen;
+	size_t i;
+
+	lb_node = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-localbus");
+	if (!lb_node)
+		return ret;
+
+	/*
+	 * The node defined as compatible with 'fsl,mpc5121-localbus'
+	 * should have two address cells and one size cell.
+	 * Every item of its ranges property should consist of:
+	 * - the first address cell which is the chipselect number;
+	 * - the second address cell which is the offset in the chipselect,
+	 *    must be zero.
+	 * - CPU address of the beginning of an access window;
+	 * - the only size cell which is the size of an access window.
+	 */
+	addr_cells_p = of_get_property(lb_node, "#address-cells", NULL);
+	size_cells_p = of_get_property(lb_node, "#size-cells", NULL);
+	if (addr_cells_p == NULL || *addr_cells_p != 2 ||
+				size_cells_p == NULL ||	*size_cells_p != 1) {
+		goto end;
+	}
+
+	proplen = of_property_count_u32_elems(lb_node, "ranges");
+	if (proplen <= 0 || proplen % 4 != 0)
+		goto end;
+
+	lpbfifo.cs_n = proplen / 4;
+	lpbfifo.cs_ranges = devm_kcalloc(dev, lpbfifo.cs_n,
+					sizeof(struct cs_range), GFP_KERNEL);
+	if (!lpbfifo.cs_ranges)
+		goto end;
+
+	if (of_property_read_u32_array(lb_node, "ranges",
+				(u32 *)lpbfifo.cs_ranges, proplen) != 0) {
+		goto end;
+	}
+
+	for (i = 0; i < lpbfifo.cs_n; i++) {
+		if (lpbfifo.cs_ranges[i].base != 0)
+			goto end;
+	}
+
+	ret = 0;
+
+ end:
+	of_node_put(lb_node);
+	return ret;
+}
+
+static int mpc512x_lpbfifo_probe(struct platform_device *pdev)
+{
+	struct resource r;
+	int ret = 0;
+
+	memset(&lpbfifo, 0, sizeof(struct lpbfifo_data));
+	spin_lock_init(&lpbfifo.lock);
+
+	lpbfifo.chan = dma_request_slave_channel(&pdev->dev, "rx-tx");
+	if (lpbfifo.chan == NULL)
+		return -EPROBE_DEFER;
+
+	if (of_address_to_resource(pdev->dev.of_node, 0, &r) != 0) {
+		dev_err(&pdev->dev, "bad 'reg' in 'sclpc' device tree node\n");
+		ret = -ENODEV;
+		goto err0;
+	}
+
+	lpbfifo.regs_phys = r.start;
+	lpbfifo.regs_size = resource_size(&r);
+
+	if (!devm_request_mem_region(&pdev->dev, lpbfifo.regs_phys,
+					lpbfifo.regs_size, DRV_NAME)) {
+		dev_err(&pdev->dev, "unable to request region\n");
+		ret = -EBUSY;
+		goto err0;
+	}
+
+	lpbfifo.regs = devm_ioremap(&pdev->dev,
+					lpbfifo.regs_phys, lpbfifo.regs_size);
+	if (!lpbfifo.regs) {
+		dev_err(&pdev->dev, "mapping registers failed\n");
+		ret = -ENOMEM;
+		goto err0;
+	}
+
+	out_be32(&lpbfifo.regs->enable,
+				MPC512X_SCLPC_RESET | MPC512X_SCLPC_FIFO_RESET);
+
+	if (get_cs_ranges(&pdev->dev) != 0) {
+		dev_err(&pdev->dev, "bad '/localbus' device tree node\n");
+		ret = -ENODEV;
+		goto err0;
+	}
+
+	lpbfifo.irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
+	if (lpbfifo.irq == NO_IRQ) {
+		dev_err(&pdev->dev, "mapping irq failed\n");
+		ret = -ENODEV;
+		goto err0;
+	}
+
+	if (request_irq(lpbfifo.irq, mpc512x_lpbfifo_irq, 0,
+						DRV_NAME, &pdev->dev) != 0) {
+		dev_err(&pdev->dev, "requesting irq failed\n");
+		ret = -ENODEV;
+		goto err1;
+	}
+
+	dev_info(&pdev->dev, "probe succeeded\n");
+	return 0;
+
+ err1:
+	irq_dispose_mapping(lpbfifo.irq);
+ err0:
+	dma_release_channel(lpbfifo.chan);
+	return ret;
+}
+
+static int mpc512x_lpbfifo_remove(struct platform_device *pdev)
+{
+	unsigned long flags;
+	struct dma_device *dma_dev = lpbfifo.chan->device;
+	struct mpc512x_lpbfifo __iomem *regs = NULL;
+
+	spin_lock_irqsave(&lpbfifo.lock, flags);
+	regs = lpbfifo.regs;
+	lpbfifo.regs = NULL;
+	spin_unlock_irqrestore(&lpbfifo.lock, flags);
+
+	dma_dev->device_terminate_all(lpbfifo.chan);
+	out_be32(&regs->enable, MPC512X_SCLPC_RESET | MPC512X_SCLPC_FIFO_RESET);
+
+	free_irq(lpbfifo.irq, &pdev->dev);
+	irq_dispose_mapping(lpbfifo.irq);
+	dma_release_channel(lpbfifo.chan);
+
+	return 0;
+}
+
+static const struct of_device_id mpc512x_lpbfifo_match[] = {
+	{ .compatible = "fsl,mpc512x-lpbfifo", },
+	{},
+};
+
+static struct platform_driver mpc512x_lpbfifo_driver = {
+	.probe = mpc512x_lpbfifo_probe,
+	.remove = mpc512x_lpbfifo_remove,
+	.driver = {
+		.name = DRV_NAME,
+		.owner = THIS_MODULE,
+		.of_match_table = mpc512x_lpbfifo_match,
+	},
+};
+
+module_platform_driver(mpc512x_lpbfifo_driver);
+
+MODULE_AUTHOR("Alexander Popov <alex.popov@xxxxxxxxx>");
+MODULE_DESCRIPTION("MPC512x LocalPlus Bus FIFO device driver");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

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