diff options
Diffstat (limited to 'arch/arm/mach-ep93xx/dma-m2p.c')
| -rw-r--r-- | arch/arm/mach-ep93xx/dma-m2p.c | 408 |
1 files changed, 408 insertions, 0 deletions
diff --git a/arch/arm/mach-ep93xx/dma-m2p.c b/arch/arm/mach-ep93xx/dma-m2p.c new file mode 100644 index 000000000000..a2df5bb7dff0 --- /dev/null +++ b/arch/arm/mach-ep93xx/dma-m2p.c @@ -0,0 +1,408 @@ +/* + * 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); |