dmaengine: driver for the ARM PL080/PL081 PrimeCells v5

This creates a DMAengine driver for the ARM PL080/PL081 PrimeCells
based on the implementation earlier submitted by Peter Pearse.
This is working like a charm for memcpy and slave DMA to the PL011
PrimeCell on the PB11MPCore.

This DMA controller is used in mostly unmodified form in the ARM
RealView and Versatile platforms, in the ST-Ericsson Nomadik, and
in the ST SPEAr platform.

It has been converted to use the header from the Samsung PL080
derivate instead of its own defintions. The Samsungs have a custom
driver in their mach-* folders though, atleast we can share the
register definitions.

Cc: Peter Pearse <peter.pearse@arm.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Alessandro Rubini <rubini@unipv.it>
Acked-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
[GFP_KERNEL to GFP_NOWAIT in pl08x_prep_dma_memcpy]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/dma/Kconfig

@@ -49,6 +49,14 @@ config INTEL_MID_DMAC
 config ASYNC_TX_DISABLE_CHANNEL_SWITCH
 	bool
 
+config AMBA_PL08X
+	bool "ARM PrimeCell PL080 or PL081 support"
+	depends on ARM_AMBA && EXPERIMENTAL
+	select DMA_ENGINE
+	help
+	  Platform has a PL08x DMAC device
+	  which can provide DMA engine support
+
 config INTEL_IOATDMA
 	tristate "Intel I/OAT DMA support"
 	depends on PCI && X86

drivers/dma/Makefile

@@ -25,3 +25,4 @@ obj-$(CONFIG_TIMB_DMA) += timb_dma.o
 obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o
 obj-$(CONFIG_PL330_DMA) += pl330.o
 obj-$(CONFIG_PCH_DMA) += pch_dma.o
+obj-$(CONFIG_AMBA_PL08X) += amba-pl08x.o

include/linux/amba/pl08x.h

@@ -0,0 +1,222 @@
+/*
+ * linux/amba/pl08x.h - ARM PrimeCell DMA Controller driver
+ *
+ * Copyright (C) 2005 ARM Ltd
+ * Copyright (C) 2010 ST-Ericsson SA
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * pl08x information required by platform code
+ *
+ * Please credit ARM.com
+ * Documentation: ARM DDI 0196D
+ *
+ */
+
+#ifndef AMBA_PL08X_H
+#define AMBA_PL08X_H
+
+/* We need sizes of structs from this header */
+#include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+
+/**
+ * struct pl08x_channel_data - data structure to pass info between
+ * platform and PL08x driver regarding channel configuration
+ * @bus_id: name of this device channel, not just a device name since
+ * devices may have more than one channel e.g. "foo_tx"
+ * @min_signal: the minimum DMA signal number to be muxed in for this
+ * channel (for platforms supporting muxed signals). If you have
+ * static assignments, make sure this is set to the assigned signal
+ * number, PL08x have 16 possible signals in number 0 thru 15 so
+ * when these are not enough they often get muxed (in hardware)
+ * disabling simultaneous use of the same channel for two devices.
+ * @max_signal: the maximum DMA signal number to be muxed in for
+ * the channel. Set to the same as min_signal for
+ * devices with static assignments
+ * @muxval: a number usually used to poke into some mux regiser to
+ * mux in the signal to this channel
+ * @cctl_opt: default options for the channel control register
+ * @addr: source/target address in physical memory for this DMA channel,
+ * can be the address of a FIFO register for burst requests for example.
+ * This can be left undefined if the PrimeCell API is used for configuring
+ * this.
+ * @circular_buffer: whether the buffer passed in is circular and
+ * shall simply be looped round round (like a record baby round
+ * round round round)
+ * @single: the device connected to this channel will request single
+ * DMA transfers, not bursts. (Bursts are default.)
+ */
+struct pl08x_channel_data {
+	char *bus_id;
+	int min_signal;
+	int max_signal;
+	u32 muxval;
+	u32 cctl;
+	u32 ccfg;
+	dma_addr_t addr;
+	bool circular_buffer;
+	bool single;
+};
+
+/**
+ * Struct pl08x_bus_data - information of source or destination
+ * busses for a transfer
+ * @addr: current address
+ * @maxwidth: the maximum width of a transfer on this bus
+ * @buswidth: the width of this bus in bytes: 1, 2 or 4
+ * @fill_bytes: bytes required to fill to the next bus memory
+ * boundary
+ */
+struct pl08x_bus_data {
+	dma_addr_t addr;
+	u8 maxwidth;
+	u8 buswidth;
+	u32 fill_bytes;
+};
+
+/**
+ * struct pl08x_phy_chan - holder for the physical channels
+ * @id: physical index to this channel
+ * @lock: a lock to use when altering an instance of this struct
+ * @signal: the physical signal (aka channel) serving this
+ * physical channel right now
+ * @serving: the virtual channel currently being served by this
+ * physical channel
+ */
+struct pl08x_phy_chan {
+	unsigned int id;
+	void __iomem *base;
+	spinlock_t lock;
+	int signal;
+	struct pl08x_dma_chan *serving;
+	u32 csrc;
+	u32 cdst;
+	u32 clli;
+	u32 cctl;
+	u32 ccfg;
+};
+
+/**
+ * struct pl08x_txd - wrapper for struct dma_async_tx_descriptor
+ * @llis_bus: DMA memory address (physical) start for the LLIs
+ * @llis_va: virtual memory address start for the LLIs
+ */
+struct pl08x_txd {
+	struct dma_async_tx_descriptor tx;
+	struct list_head node;
+	enum dma_data_direction	direction;
+	struct pl08x_bus_data srcbus;
+	struct pl08x_bus_data dstbus;
+	int len;
+	dma_addr_t llis_bus;
+	void *llis_va;
+	struct pl08x_channel_data *cd;
+	bool active;
+	/*
+	 * Settings to be put into the physical channel when we
+	 * trigger this txd
+	 */
+	u32 csrc;
+	u32 cdst;
+	u32 clli;
+	u32 cctl;
+};
+
+/**
+ * struct pl08x_dma_chan_state - holds the PL08x specific virtual
+ * channel states
+ * @PL08X_CHAN_IDLE: the channel is idle
+ * @PL08X_CHAN_RUNNING: the channel has allocated a physical transport
+ * channel and is running a transfer on it
+ * @PL08X_CHAN_PAUSED: the channel has allocated a physical transport
+ * channel, but the transfer is currently paused
+ * @PL08X_CHAN_WAITING: the channel is waiting for a physical transport
+ * channel to become available (only pertains to memcpy channels)
+ */
+enum pl08x_dma_chan_state {
+	PL08X_CHAN_IDLE,
+	PL08X_CHAN_RUNNING,
+	PL08X_CHAN_PAUSED,
+	PL08X_CHAN_WAITING,
+};
+
+/**
+ * struct pl08x_dma_chan - this structure wraps a DMA ENGINE channel
+ * @chan: wrappped abstract channel
+ * @phychan: the physical channel utilized by this channel, if there is one
+ * @tasklet: tasklet scheduled by the IRQ to handle actual work etc
+ * @name: name of channel
+ * @cd: channel platform data
+ * @runtime_addr: address for RX/TX according to the runtime config
+ * @runtime_direction: current direction of this channel according to
+ * runtime config
+ * @lc: last completed transaction on this channel
+ * @desc_list: queued transactions pending on this channel
+ * @at: active transaction on this channel
+ * @lockflags: sometimes we let a lock last between two function calls,
+ * especially prep/submit, and then we need to store the IRQ flags
+ * in the channel state, here
+ * @lock: a lock for this channel data
+ * @host: a pointer to the host (internal use)
+ * @state: whether the channel is idle, paused, running etc
+ * @slave: whether this channel is a device (slave) or for memcpy
+ * @waiting: a TX descriptor on this channel which is waiting for
+ * a physical channel to become available
+ */
+struct pl08x_dma_chan {
+	struct dma_chan chan;
+	struct pl08x_phy_chan *phychan;
+	struct tasklet_struct tasklet;
+	char *name;
+	struct pl08x_channel_data *cd;
+	dma_addr_t runtime_addr;
+	enum dma_data_direction	runtime_direction;
+	atomic_t last_issued;
+	dma_cookie_t lc;
+	struct list_head desc_list;
+	struct pl08x_txd *at;
+	unsigned long lockflags;
+	spinlock_t lock;
+	void *host;
+	enum pl08x_dma_chan_state state;
+	bool slave;
+	struct pl08x_txd *waiting;
+};
+
+/**
+ * struct pl08x_platform_data - the platform configuration for the
+ * PL08x PrimeCells.
+ * @slave_channels: the channels defined for the different devices on the
+ * platform, all inclusive, including multiplexed channels. The available
+ * physical channels will be multiplexed around these signals as they
+ * are requested, just enumerate all possible channels.
+ * @get_signal: request a physical signal to be used for a DMA
+ * transfer immediately: if there is some multiplexing or similar blocking
+ * the use of the channel the transfer can be denied by returning
+ * less than zero, else it returns the allocated signal number
+ * @put_signal: indicate to the platform that this physical signal is not
+ * running any DMA transfer and multiplexing can be recycled
+ * @bus_bit_lli: Bit[0] of the address indicated which AHB bus master the
+ * LLI addresses are on 0/1 Master 1/2.
+ */
+struct pl08x_platform_data {
+	struct pl08x_channel_data *slave_channels;
+	unsigned int num_slave_channels;
+	struct pl08x_channel_data memcpy_channel;
+	int (*get_signal)(struct pl08x_dma_chan *);
+	void (*put_signal)(struct pl08x_dma_chan *);
+};
+
+#ifdef CONFIG_AMBA_PL08X
+bool pl08x_filter_id(struct dma_chan *chan, void *chan_id);
+#else
+static inline bool pl08x_filter_id(struct dma_chan *chan, void *chan_id)
+{
+	return false;
+}
+#endif
+
+#endif	/* AMBA_PL08X_H */