dmaengine: add an shdma-base library

This patch extracts code from shdma.c, that does not directly deal with
hardware implementation details and can be re-used with diverse DMA
controller variants, found on SH-based SoCs.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>

1 files changed, 123 insertions, 0 deletions

diff --git a/include/linux/shdma-base.h b/include/linux/shdma-base.h
new file mode 100644
index 000000000000..83efd1332b39
--- /dev/null
+++ b/include/linux/shdma-base.h
@@ -0,0 +1,123 @@
+/*
+ * Dmaengine driver base library for DMA controllers, found on SH-based SoCs
+ *
+ * extracted from shdma.c and headers
+ *
+ * Copyright (C) 2011-2012 Guennadi Liakhovetski <g.liakhovetski@gmx.de>
+ * Copyright (C) 2009 Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
+ * Copyright (C) 2009 Renesas Solutions, Inc. All rights reserved.
+ * Copyright (C) 2007 Freescale Semiconductor, Inc. All rights reserved.
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef SHDMA_BASE_H
+#define SHDMA_BASE_H
+
+#include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/types.h>
+
+/**
+ * shdma_pm_state - DMA channel PM state
+ * SHDMA_PM_ESTABLISHED:        either idle or during data transfer
+ * SHDMA_PM_BUSY:               during the transfer preparation, when we have to
+ *                              drop the lock temporarily
+ * SHDMA_PM_PENDING:    transfers pending
+ */
+enum shdma_pm_state {
+        SHDMA_PM_ESTABLISHED,
+        SHDMA_PM_BUSY,
+        SHDMA_PM_PENDING,
+};
+
+struct device;
+
+/*
+ * Drivers, using this library are expected to embed struct shdma_dev,
+ * struct shdma_chan, struct shdma_desc, and struct shdma_slave
+ * in their respective device, channel, descriptor and slave objects.
+ */
+
+struct shdma_slave {
+        unsigned int slave_id;
+};
+
+struct shdma_desc {
+        struct list_head node;
+        struct dma_async_tx_descriptor async_tx;
+        enum dma_transfer_direction direction;
+        dma_cookie_t cookie;
+        int chunks;
+        int mark;
+};
+
+struct shdma_chan {
+        spinlock_t chan_lock;           /* Channel operation lock */
+        struct list_head ld_queue;      /* Link descriptors queue */
+        struct list_head ld_free;       /* Free link descriptors */
+        struct dma_chan dma_chan;       /* DMA channel */
+        struct device *dev;             /* Channel device */
+        void *desc;                     /* buffer for descriptor array */
+        int desc_num;                   /* desc count */
+        size_t max_xfer_len;            /* max transfer length */
+        int id;                         /* Raw id of this channel */
+        int irq;                        /* Channel IRQ */
+        enum shdma_pm_state pm_state;
+};
+
+/**
+ * struct shdma_ops - simple DMA driver operations
+ * desc_completed:      return true, if this is the descriptor, that just has
+ *                      completed (atomic)
+ * halt_channel:        stop DMA channel operation (atomic)
+ * channel_busy:        return true, if the channel is busy (atomic)
+ * slave_addr:          return slave DMA address
+ * desc_setup:          set up the hardware specific descriptor portion (atomic)
+ * set_slave:           bind channel to a slave
+ * setup_xfer:          configure channel hardware for operation (atomic)
+ * start_xfer:          start the DMA transfer (atomic)
+ * embedded_desc:       return Nth struct shdma_desc pointer from the
+ *                      descriptor array
+ * chan_irq:            process channel IRQ, return true if a transfer has
+ *                      completed (atomic)
+ */
+struct shdma_ops {
+        bool (*desc_completed)(struct shdma_chan *, struct shdma_desc *);
+        void (*halt_channel)(struct shdma_chan *);
+        bool (*channel_busy)(struct shdma_chan *);
+        dma_addr_t (*slave_addr)(struct shdma_chan *);
+        int (*desc_setup)(struct shdma_chan *, struct shdma_desc *,
+                          dma_addr_t, dma_addr_t, size_t *);
+        int (*set_slave)(struct shdma_chan *, struct shdma_slave *);
+        void (*setup_xfer)(struct shdma_chan *, struct shdma_slave *);
+        void (*start_xfer)(struct shdma_chan *, struct shdma_desc *);
+        struct shdma_desc *(*embedded_desc)(void *, int);
+        bool (*chan_irq)(struct shdma_chan *, int);
+};
+
+struct shdma_dev {
+        struct dma_device dma_dev;
+        struct shdma_chan **schan;
+        const struct shdma_ops *ops;
+        size_t desc_size;
+};
+
+#define shdma_for_each_chan(c, d, i) for (i = 0, c = (d)->schan[0]; \
+                                i < (d)->dma_dev.chancnt; c = (d)->schan[++i])
+
+int shdma_request_irq(struct shdma_chan *, int,
+                           unsigned long, const char *);
+void shdma_free_irq(struct shdma_chan *);
+bool shdma_reset(struct shdma_dev *sdev);
+void shdma_chan_probe(struct shdma_dev *sdev,
+                           struct shdma_chan *schan, int id);
+void shdma_chan_remove(struct shdma_chan *schan);
+int shdma_init(struct device *dev, struct shdma_dev *sdev,
+                    int chan_num);
+void shdma_cleanup(struct shdma_dev *sdev);
+
+#endif