--- /dev/null
+/*
+ * arch/arm/mach-ep93xx/dma-m2p.c
+ * M2P DMA handling for Cirrus EP93xx chips.
+ *
+ * Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
+ * Copyright (C) 2006 Applied Data Systems
+ *
+ * Copyright (C) 2009 Ryan Mallon <ryan@bluewatersys.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ */
+
+/*
+ * On the EP93xx chip the following peripherals my be allocated to the 10
+ * Memory to Internal Peripheral (M2P) channels (5 transmit + 5 receive).
+ *
+ * I2S contains 3 Tx and 3 Rx DMA Channels
+ * AAC contains 3 Tx and 3 Rx DMA Channels
+ * UART1 contains 1 Tx and 1 Rx DMA Channels
+ * UART2 contains 1 Tx and 1 Rx DMA Channels
+ * UART3 contains 1 Tx and 1 Rx DMA Channels
+ * IrDA contains 1 Tx and 1 Rx DMA Channels
+ *
+ * SSP and IDE use the Memory to Memory (M2M) channels and are not covered
+ * with this implementation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+
+#include <mach/dma.h>
+#include <mach/hardware.h>
+
+#define M2P_CONTROL 0x00
+#define M2P_CONTROL_STALL_IRQ_EN (1 << 0)
+#define M2P_CONTROL_NFB_IRQ_EN (1 << 1)
+#define M2P_CONTROL_ERROR_IRQ_EN (1 << 3)
+#define M2P_CONTROL_ENABLE (1 << 4)
+#define M2P_INTERRUPT 0x04
+#define M2P_INTERRUPT_STALL (1 << 0)
+#define M2P_INTERRUPT_NFB (1 << 1)
+#define M2P_INTERRUPT_ERROR (1 << 3)
+#define M2P_PPALLOC 0x08
+#define M2P_STATUS 0x0c
+#define M2P_REMAIN 0x14
+#define M2P_MAXCNT0 0x20
+#define M2P_BASE0 0x24
+#define M2P_MAXCNT1 0x30
+#define M2P_BASE1 0x34
+
+#define STATE_IDLE 0 /* Channel is inactive. */
+#define STATE_STALL 1 /* Channel is active, no buffers pending. */
+#define STATE_ON 2 /* Channel is active, one buffer pending. */
+#define STATE_NEXT 3 /* Channel is active, two buffers pending. */
+
+struct m2p_channel {
+ char *name;
+ void __iomem *base;
+ int irq;
+
+ struct clk *clk;
+ spinlock_t lock;
+
+ void *client;
+ unsigned next_slot:1;
+ struct ep93xx_dma_buffer *buffer_xfer;
+ struct ep93xx_dma_buffer *buffer_next;
+ struct list_head buffers_pending;
+};
+
+static struct m2p_channel m2p_rx[] = {
+ {"m2p1", EP93XX_DMA_BASE + 0x0040, IRQ_EP93XX_DMAM2P1},
+ {"m2p3", EP93XX_DMA_BASE + 0x00c0, IRQ_EP93XX_DMAM2P3},
+ {"m2p5", EP93XX_DMA_BASE + 0x0200, IRQ_EP93XX_DMAM2P5},
+ {"m2p7", EP93XX_DMA_BASE + 0x0280, IRQ_EP93XX_DMAM2P7},
+ {"m2p9", EP93XX_DMA_BASE + 0x0300, IRQ_EP93XX_DMAM2P9},
+ {NULL},
+};
+
+static struct m2p_channel m2p_tx[] = {
+ {"m2p0", EP93XX_DMA_BASE + 0x0000, IRQ_EP93XX_DMAM2P0},
+ {"m2p2", EP93XX_DMA_BASE + 0x0080, IRQ_EP93XX_DMAM2P2},
+ {"m2p4", EP93XX_DMA_BASE + 0x0240, IRQ_EP93XX_DMAM2P4},
+ {"m2p6", EP93XX_DMA_BASE + 0x02c0, IRQ_EP93XX_DMAM2P6},
+ {"m2p8", EP93XX_DMA_BASE + 0x0340, IRQ_EP93XX_DMAM2P8},
+ {NULL},
+};
+
+static void feed_buf(struct m2p_channel *ch, struct ep93xx_dma_buffer *buf)
+{
+ if (ch->next_slot == 0) {
+ writel(buf->size, ch->base + M2P_MAXCNT0);
+ writel(buf->bus_addr, ch->base + M2P_BASE0);
+ } else {
+ writel(buf->size, ch->base + M2P_MAXCNT1);
+ writel(buf->bus_addr, ch->base + M2P_BASE1);
+ }
+ ch->next_slot ^= 1;
+}
+
+static void choose_buffer_xfer(struct m2p_channel *ch)
+{
+ struct ep93xx_dma_buffer *buf;
+
+ ch->buffer_xfer = NULL;
+ if (!list_empty(&ch->buffers_pending)) {
+ buf = list_entry(ch->buffers_pending.next,
+ struct ep93xx_dma_buffer, list);
+ list_del(&buf->list);
+ feed_buf(ch, buf);
+ ch->buffer_xfer = buf;
+ }
+}
+
+static void choose_buffer_next(struct m2p_channel *ch)
+{
+ struct ep93xx_dma_buffer *buf;
+
+ ch->buffer_next = NULL;
+ if (!list_empty(&ch->buffers_pending)) {
+ buf = list_entry(ch->buffers_pending.next,
+ struct ep93xx_dma_buffer, list);
+ list_del(&buf->list);
+ feed_buf(ch, buf);
+ ch->buffer_next = buf;
+ }
+}
+
+static inline void m2p_set_control(struct m2p_channel *ch, u32 v)
+{
+ /*
+ * The control register must be read immediately after being written so
+ * that the internal state machine is correctly updated. See the ep93xx
+ * users' guide for details.
+ */
+ writel(v, ch->base + M2P_CONTROL);
+ readl(ch->base + M2P_CONTROL);
+}
+
+static inline int m2p_channel_state(struct m2p_channel *ch)
+{
+ return (readl(ch->base + M2P_STATUS) >> 4) & 0x3;
+}
+
+static irqreturn_t m2p_irq(int irq, void *dev_id)
+{
+ struct m2p_channel *ch = dev_id;
+ struct ep93xx_dma_m2p_client *cl;
+ u32 irq_status, v;
+ int error = 0;
+
+ cl = ch->client;
+
+ spin_lock(&ch->lock);
+ irq_status = readl(ch->base + M2P_INTERRUPT);
+
+ if (irq_status & M2P_INTERRUPT_ERROR) {
+ writel(M2P_INTERRUPT_ERROR, ch->base + M2P_INTERRUPT);
+ error = 1;
+ }
+
+ if ((irq_status & (M2P_INTERRUPT_STALL | M2P_INTERRUPT_NFB)) == 0) {
+ spin_unlock(&ch->lock);
+ return IRQ_NONE;
+ }
+
+ switch (m2p_channel_state(ch)) {
+ case STATE_IDLE:
+ pr_crit("m2p_irq: dma interrupt without a dma buffer\n");
+ BUG();
+ break;
+
+ case STATE_STALL:
+ cl->buffer_finished(cl->cookie, ch->buffer_xfer, 0, error);
+ if (ch->buffer_next != NULL) {
+ cl->buffer_finished(cl->cookie, ch->buffer_next,
+ 0, error);
+ }
+ choose_buffer_xfer(ch);
+ choose_buffer_next(ch);
+ if (ch->buffer_xfer != NULL)
+ cl->buffer_started(cl->cookie, ch->buffer_xfer);
+ break;
+
+ case STATE_ON:
+ cl->buffer_finished(cl->cookie, ch->buffer_xfer, 0, error);
+ ch->buffer_xfer = ch->buffer_next;
+ choose_buffer_next(ch);
+ cl->buffer_started(cl->cookie, ch->buffer_xfer);
+ break;
+
+ case STATE_NEXT:
+ pr_crit("m2p_irq: dma interrupt while next\n");
+ BUG();
+ break;
+ }
+
+ v = readl(ch->base + M2P_CONTROL) & ~(M2P_CONTROL_STALL_IRQ_EN |
+ M2P_CONTROL_NFB_IRQ_EN);
+ if (ch->buffer_xfer != NULL)
+ v |= M2P_CONTROL_STALL_IRQ_EN;
+ if (ch->buffer_next != NULL)
+ v |= M2P_CONTROL_NFB_IRQ_EN;
+ m2p_set_control(ch, v);
+
+ spin_unlock(&ch->lock);
+ return IRQ_HANDLED;
+}
+
+static struct m2p_channel *find_free_channel(struct ep93xx_dma_m2p_client *cl)
+{
+ struct m2p_channel *ch;
+ int i;
+
+ if (cl->flags & EP93XX_DMA_M2P_RX)
+ ch = m2p_rx;
+ else
+ ch = m2p_tx;
+
+ for (i = 0; ch[i].base; i++) {
+ struct ep93xx_dma_m2p_client *client;
+
+ client = ch[i].client;
+ if (client != NULL) {
+ int port;
+
+ port = cl->flags & EP93XX_DMA_M2P_PORT_MASK;
+ if (port == (client->flags &
+ EP93XX_DMA_M2P_PORT_MASK)) {
+ pr_warning("DMA channel already used by %s\n",
+ cl->name ? : "unknown client");
+ return ERR_PTR(-EBUSY);
+ }
+ }
+ }
+
+ for (i = 0; ch[i].base; i++) {
+ if (ch[i].client == NULL)
+ return ch + i;
+ }
+
+ pr_warning("No free DMA channel for %s\n",
+ cl->name ? : "unknown client");
+ return ERR_PTR(-ENODEV);
+}
+
+static void channel_enable(struct m2p_channel *ch)
+{
+ struct ep93xx_dma_m2p_client *cl = ch->client;
+ u32 v;
+
+ clk_enable(ch->clk);
+
+ v = cl->flags & EP93XX_DMA_M2P_PORT_MASK;
+ writel(v, ch->base + M2P_PPALLOC);
+
+ v = cl->flags & EP93XX_DMA_M2P_ERROR_MASK;
+ v |= M2P_CONTROL_ENABLE | M2P_CONTROL_ERROR_IRQ_EN;
+ m2p_set_control(ch, v);
+}
+
+static void channel_disable(struct m2p_channel *ch)
+{
+ u32 v;
+
+ v = readl(ch->base + M2P_CONTROL);
+ v &= ~(M2P_CONTROL_STALL_IRQ_EN | M2P_CONTROL_NFB_IRQ_EN);
+ m2p_set_control(ch, v);
+
+ while (m2p_channel_state(ch) == STATE_ON)
+ cpu_relax();
+
+ m2p_set_control(ch, 0x0);
+
+ while (m2p_channel_state(ch) == STATE_STALL)
+ cpu_relax();
+
+ clk_disable(ch->clk);
+}
+
+int ep93xx_dma_m2p_client_register(struct ep93xx_dma_m2p_client *cl)
+{
+ struct m2p_channel *ch;
+ int err;
+
+ ch = find_free_channel(cl);
+ if (IS_ERR(ch))
+ return PTR_ERR(ch);
+
+ err = request_irq(ch->irq, m2p_irq, 0, cl->name ? : "dma-m2p", ch);
+ if (err)
+ return err;
+
+ ch->client = cl;
+ ch->next_slot = 0;
+ ch->buffer_xfer = NULL;
+ ch->buffer_next = NULL;
+ INIT_LIST_HEAD(&ch->buffers_pending);
+
+ cl->channel = ch;
+
+ channel_enable(ch);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ep93xx_dma_m2p_client_register);
+
+void ep93xx_dma_m2p_client_unregister(struct ep93xx_dma_m2p_client *cl)
+{
+ struct m2p_channel *ch = cl->channel;
+
+ channel_disable(ch);
+ free_irq(ch->irq, ch);
+ ch->client = NULL;
+}
+EXPORT_SYMBOL_GPL(ep93xx_dma_m2p_client_unregister);
+
+void ep93xx_dma_m2p_submit(struct ep93xx_dma_m2p_client *cl,
+ struct ep93xx_dma_buffer *buf)
+{
+ struct m2p_channel *ch = cl->channel;
+ unsigned long flags;
+ u32 v;
+
+ spin_lock_irqsave(&ch->lock, flags);
+ v = readl(ch->base + M2P_CONTROL);
+ if (ch->buffer_xfer == NULL) {
+ ch->buffer_xfer = buf;
+ feed_buf(ch, buf);
+ cl->buffer_started(cl->cookie, buf);
+
+ v |= M2P_CONTROL_STALL_IRQ_EN;
+ m2p_set_control(ch, v);
+
+ } else if (ch->buffer_next == NULL) {
+ ch->buffer_next = buf;
+ feed_buf(ch, buf);
+
+ v |= M2P_CONTROL_NFB_IRQ_EN;
+ m2p_set_control(ch, v);
+ } else {
+ list_add_tail(&buf->list, &ch->buffers_pending);
+ }
+ spin_unlock_irqrestore(&ch->lock, flags);
+}
+EXPORT_SYMBOL_GPL(ep93xx_dma_m2p_submit);
+
+void ep93xx_dma_m2p_submit_recursive(struct ep93xx_dma_m2p_client *cl,
+ struct ep93xx_dma_buffer *buf)
+{
+ struct m2p_channel *ch = cl->channel;
+
+ list_add_tail(&buf->list, &ch->buffers_pending);
+}
+EXPORT_SYMBOL_GPL(ep93xx_dma_m2p_submit_recursive);
+
+void ep93xx_dma_m2p_flush(struct ep93xx_dma_m2p_client *cl)
+{
+ struct m2p_channel *ch = cl->channel;
+
+ channel_disable(ch);
+ ch->next_slot = 0;
+ ch->buffer_xfer = NULL;
+ ch->buffer_next = NULL;
+ INIT_LIST_HEAD(&ch->buffers_pending);
+ channel_enable(ch);
+}
+EXPORT_SYMBOL_GPL(ep93xx_dma_m2p_flush);
+
+static int init_channel(struct m2p_channel *ch)
+{
+ ch->clk = clk_get(NULL, ch->name);
+ if (IS_ERR(ch->clk))
+ return PTR_ERR(ch->clk);
+
+ spin_lock_init(&ch->lock);
+ ch->client = NULL;
+
+ return 0;
+}
+
+static int __init ep93xx_dma_m2p_init(void)
+{
+ int i;
+ int ret;
+
+ for (i = 0; m2p_rx[i].base; i++) {
+ ret = init_channel(m2p_rx + i);
+ if (ret)
+ return ret;
+ }
+
+ for (i = 0; m2p_tx[i].base; i++) {
+ ret = init_channel(m2p_tx + i);
+ if (ret)
+ return ret;
+ }
+
+ pr_info("M2P DMA subsystem initialized\n");
+ return 0;
+}
+arch_initcall(ep93xx_dma_m2p_init);
git.openpandora.org / pandora-kernel.git / commitdiff