[POWERPC] bestcomm: core bestcomm support for Freescale MPC5200

This patch adds support for the core of the BestComm API
for the Freescale MPC5200(b). The BestComm engine is a
microcode-controlled / tasks-based DMA used by several
of the onchip devices.

Setting up the tasks / memory allocation and all common
low level functions are handled by this patch.
The specifics details of each tasks and their microcode
are split-out in separate patches.

This is not the official API, but a much cleaner one.
(hopefully)

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 190 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/bestcomm/bestcomm.h b/arch/powerpc/sysdev/bestcomm/bestcomm.h
new file mode 100644
index 00000000000..e802cb4eb69
--- /dev/null
+++ b/arch/powerpc/sysdev/bestcomm/bestcomm.h
@@ -0,0 +1,190 @@
+/*
+ * Public header for the MPC52xx processor BestComm driver
+ *
+ *
+ * Copyright (C) 2006      Sylvain Munaut <tnt@246tNt.com>
+ * Copyright (C) 2005      Varma Electronics Oy,
+ *                         ( by Andrey Volkov <avolkov@varma-el.com> )
+ * Copyright (C) 2003-2004 MontaVista, Software, Inc.
+ *                         ( by Dale Farnsworth <dfarnsworth@mvista.com> )
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#ifndef __BESTCOMM_H__
+#define __BESTCOMM_H__
+
+struct bcom_bd; /* defined later on ... */
+
+
+/* ======================================================================== */
+/* Generic task managment                                                   */
+/* ======================================================================== */
+
+/**
+ * struct bcom_task - Structure describing a loaded BestComm task
+ *
+ * This structure is never built by the driver it self. It's built and
+ * filled the intermediate layer of the BestComm API, the task dependent
+ * support code.
+ *
+ * Most likely you don't need to poke around inside this structure. The
+ * fields are exposed in the header just for the sake of inline functions
+ */
+struct bcom_task {
+	unsigned int	tasknum;
+	unsigned int	flags;
+	int		irq;
+
+	struct bcom_bd	*bd;
+	phys_addr_t	bd_pa;
+	void		**cookie;
+	unsigned short	index;
+	unsigned short	outdex;
+	unsigned int	num_bd;
+	unsigned int	bd_size;
+
+	void*		priv;
+};
+
+#define BCOM_FLAGS_NONE         0x00000000ul
+#define BCOM_FLAGS_ENABLE_TASK  (1ul <<  0)
+
+/**
+ * bcom_enable - Enable a BestComm task
+ * @tsk: The BestComm task structure
+ *
+ * This function makes sure the given task is enabled and can be run
+ * by the BestComm engine as needed
+ */
+extern void bcom_enable(struct bcom_task *tsk);
+
+/**
+ * bcom_disable - Disable a BestComm task
+ * @tsk: The BestComm task structure
+ *
+ * This function disable a given task, making sure it's not executed
+ * by the BestComm engine.
+ */
+extern void bcom_disable(struct bcom_task *tsk);
+
+
+/**
+ * bcom_get_task_irq - Returns the irq number of a BestComm task
+ * @tsk: The BestComm task structure
+ */
+static inline int
+bcom_get_task_irq(struct bcom_task *tsk) {
+	return tsk->irq;
+}
+
+/* ======================================================================== */
+/* BD based tasks helpers                                                   */
+/* ======================================================================== */
+
+/**
+ * struct bcom_bd - Structure describing a generic BestComm buffer descriptor
+ * @status: The current status of this buffer. Exact meaning depends on the
+ *          task type
+ * @data: An array of u32 whose meaning depends on the task type.
+ */
+struct bcom_bd {
+	u32	status;
+	u32	data[1];	/* variable, but at least 1 */
+};
+
+#define BCOM_BD_READY	0x40000000ul
+
+/** _bcom_next_index - Get next input index.
+ * @tsk: pointer to task structure
+ *
+ * Support function; Device drivers should not call this
+ */
+static inline int
+_bcom_next_index(struct bcom_task *tsk)
+{
+	return ((tsk->index + 1) == tsk->num_bd) ? 0 : tsk->index + 1;
+}
+
+/** _bcom_next_outdex - Get next output index.
+ * @tsk: pointer to task structure
+ *
+ * Support function; Device drivers should not call this
+ */
+static inline int
+_bcom_next_outdex(struct bcom_task *tsk)
+{
+	return ((tsk->outdex + 1) == tsk->num_bd) ? 0 : tsk->outdex + 1;
+}
+
+/**
+ * bcom_queue_empty - Checks if a BestComm task BD queue is empty
+ * @tsk: The BestComm task structure
+ */
+static inline int
+bcom_queue_empty(struct bcom_task *tsk)
+{
+	return tsk->index == tsk->outdex;
+}
+
+/**
+ * bcom_queue_full - Checks if a BestComm task BD queue is full
+ * @tsk: The BestComm task structure
+ */
+static inline int
+bcom_queue_full(struct bcom_task *tsk)
+{
+	return tsk->outdex == _bcom_next_index(tsk);
+}
+
+/**
+ * bcom_buffer_done - Checks if a BestComm 
+ * @tsk: The BestComm task structure
+ */
+static inline int
+bcom_buffer_done(struct bcom_task *tsk)
+{
+	if (bcom_queue_empty(tsk))
+		return 0;
+	return !(tsk->bd[tsk->outdex].status & BCOM_BD_READY);
+}
+
+/**
+ * bcom_prepare_next_buffer - clear status of next available buffer.
+ * @tsk: The BestComm task structure
+ *
+ * Returns pointer to next buffer descriptor
+ */
+static inline struct bcom_bd *
+bcom_prepare_next_buffer(struct bcom_task *tsk)
+{
+	tsk->bd[tsk->index].status = 0;	/* cleanup last status */
+	return &tsk->bd[tsk->index];
+}
+
+static inline void
+bcom_submit_next_buffer(struct bcom_task *tsk, void *cookie)
+{
+	tsk->cookie[tsk->index] = cookie;
+	mb();	/* ensure the bd is really up-to-date */
+	tsk->bd[tsk->index].status |= BCOM_BD_READY;
+	tsk->index = _bcom_next_index(tsk);
+	if (tsk->flags & BCOM_FLAGS_ENABLE_TASK)
+		bcom_enable(tsk);
+}
+
+static inline void *
+bcom_retrieve_buffer(struct bcom_task *tsk, u32 *p_status, struct bcom_bd **p_bd)
+{
+	void *cookie = tsk->cookie[tsk->outdex];
+	if (p_status)
+		*p_status = tsk->bd[tsk->outdex].status;
+	if (p_bd)
+		*p_bd = &tsk->bd[tsk->outdex];
+	tsk->outdex = _bcom_next_outdex(tsk);
+	return cookie;
+}
+
+#endif /* __BESTCOMM_H__ */