[ARM] S3C64XX: DMA support

Add support for the DMA blocks in the S3C64XX series of CPUS,
which are based on the ARM PL080 PrimeCell system.

Unfortunately, these DMA controllers diverge from the PL080
design by adding another DMA controller register and
configuration for OneNAND.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

1 files changed, 722 insertions, 0 deletions

diff --git a/arch/arm/plat-s3c64xx/dma.c b/arch/arm/plat-s3c64xx/dma.c
new file mode 100644
index 000000000000..1c0f51cbcd89
--- /dev/null
+++ b/arch/arm/plat-s3c64xx/dma.c
@@ -0,0 +1,722 @@
+/* linux/arch/arm/plat-s3c64xx/dma.c
+ *
+ * Copyright 2009 Openmoko, Inc.
+ * Copyright 2009 Simtec Electronics
+ *      Ben Dooks <ben@simtec.co.uk>
+ *      http://armlinux.simtec.co.uk/
+ *
+ * S3C64XX DMA core
+ *
+ * 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.
+*/
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/dmapool.h>
+#include <linux/sysdev.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+
+#include <mach/dma.h>
+#include <mach/map.h>
+#include <mach/irqs.h>
+
+#include <plat/dma-plat.h>
+#include <plat/regs-sys.h>
+
+#include <asm/hardware/pl080.h>
+
+/* dma channel state information */
+
+struct s3c64xx_dmac {
+        struct sys_device        sysdev;
+        struct clk              *clk;
+        void __iomem            *regs;
+        struct s3c2410_dma_chan *channels;
+        enum dma_ch              chanbase;
+};
+
+/* pool to provide LLI buffers */
+static struct dma_pool *dma_pool;
+
+/* Debug configuration and code */
+
+static unsigned char debug_show_buffs = 0;
+
+static void dbg_showchan(struct s3c2410_dma_chan *chan)
+{
+        pr_debug("DMA%d: %08x->%08x L %08x C %08x,%08x S %08x\n",
+                 chan->number,
+                 readl(chan->regs + PL080_CH_SRC_ADDR),
+                 readl(chan->regs + PL080_CH_DST_ADDR),
+                 readl(chan->regs + PL080_CH_LLI),
+                 readl(chan->regs + PL080_CH_CONTROL),
+                 readl(chan->regs + PL080S_CH_CONTROL2),
+                 readl(chan->regs + PL080S_CH_CONFIG));
+}
+
+static void show_lli(struct pl080s_lli *lli)
+{
+        pr_debug("LLI[%p] %08x->%08x, NL %08x C %08x,%08x\n",
+                 lli, lli->src_addr, lli->dst_addr, lli->next_lli,
+                 lli->control0, lli->control1);
+}
+
+static void dbg_showbuffs(struct s3c2410_dma_chan *chan)
+{
+        struct s3c64xx_dma_buff *ptr;
+        struct s3c64xx_dma_buff *end;
+
+        pr_debug("DMA%d: buffs next %p, curr %p, end %p\n",
+                 chan->number, chan->next, chan->curr, chan->end);
+
+        ptr = chan->next;
+        end = chan->end;
+
+        if (debug_show_buffs) {
+                for (; ptr != NULL; ptr = ptr->next) {
+                        pr_debug("DMA%d: %08x ",
+                                 chan->number, ptr->lli_dma);
+                        show_lli(ptr->lli);
+                }
+        }
+}
+
+/* End of Debug */
+
+static struct s3c2410_dma_chan *s3c64xx_dma_map_channel(unsigned int channel)
+{
+        struct s3c2410_dma_chan *chan;
+        unsigned int start, offs;
+
+        start = 0;
+
+        if (channel >= DMACH_PCM1_TX)
+                start = 8;
+
+        for (offs = 0; offs < 8; offs++) {
+                chan = &s3c2410_chans[start + offs];
+                if (!chan->in_use)
+                        goto found;
+        }
+
+        return NULL;
+
+found:
+        s3c_dma_chan_map[channel] = chan;
+        return chan;
+}
+
+int s3c2410_dma_config(unsigned int channel, int xferunit)
+{
+        struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
+
+        if (chan == NULL)
+                return -EINVAL;
+
+        switch (xferunit) {
+        case 1:
+                chan->hw_width = 0;
+                break;
+        case 2:
+                chan->hw_width = 1;
+                break;
+        case 4:
+                chan->hw_width = 2;
+                break;
+        default:
+                printk(KERN_ERR "%s: illegal width %d\n", __func__, xferunit);
+                return -EINVAL;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL(s3c2410_dma_config);
+
+static void s3c64xx_dma_fill_lli(struct s3c2410_dma_chan *chan,
+                                 struct pl080s_lli *lli,
+                                 dma_addr_t data, int size)
+{
+        dma_addr_t src, dst;
+        u32 control0, control1;
+
+        switch (chan->source) {
+        case S3C2410_DMASRC_HW:
+                src = chan->dev_addr;
+                dst = data;
+                control0 = PL080_CONTROL_SRC_AHB2;
+                control0 |= (u32)chan->hw_width << PL080_CONTROL_SWIDTH_SHIFT;
+                control0 |= 2 << PL080_CONTROL_DWIDTH_SHIFT;
+                control0 |= PL080_CONTROL_DST_INCR;
+                break;
+
+        case S3C2410_DMASRC_MEM:
+                src = data;
+                dst = chan->dev_addr;
+                control0 = PL080_CONTROL_DST_AHB2;
+                control0 |= (u32)chan->hw_width << PL080_CONTROL_DWIDTH_SHIFT;
+                control0 |= 2 << PL080_CONTROL_SWIDTH_SHIFT;
+                control0 |= PL080_CONTROL_SRC_INCR;
+                break;
+        default:
+                BUG();
+        }
+
+        /* note, we do not currently setup any of the burst controls */
+
+        control1 = size >> chan->hw_width;      /* size in no of xfers */
+        control0 |= PL080_CONTROL_PROT_SYS;     /* always in priv. mode */
+        control0 |= PL080_CONTROL_TC_IRQ_EN;    /* always fire IRQ */
+
+        lli->src_addr = src;
+        lli->dst_addr = dst;
+        lli->next_lli = 0;
+        lli->control0 = control0;
+        lli->control1 = control1;
+}
+
+static void s3c64xx_lli_to_regs(struct s3c2410_dma_chan *chan,
+                                struct pl080s_lli *lli)
+{
+        void __iomem *regs = chan->regs;
+
+        pr_debug("%s: LLI %p => regs\n", __func__, lli);
+        show_lli(lli);
+
+        writel(lli->src_addr, regs + PL080_CH_SRC_ADDR);
+        writel(lli->dst_addr, regs + PL080_CH_DST_ADDR);
+        writel(lli->next_lli, regs + PL080_CH_LLI);
+        writel(lli->control0, regs + PL080_CH_CONTROL);
+        writel(lli->control1, regs + PL080S_CH_CONTROL2);
+}
+
+static int s3c64xx_dma_start(struct s3c2410_dma_chan *chan)
+{
+        struct s3c64xx_dmac *dmac = chan->dmac;
+        u32 config;
+        u32 bit = chan->bit;
+
+        dbg_showchan(chan);
+
+        pr_debug("%s: clearing interrupts\n", __func__);
+
+        /* clear interrupts */
+        writel(bit, dmac->regs + PL080_TC_CLEAR);
+        writel(bit, dmac->regs + PL080_ERR_CLEAR);
+
+        pr_debug("%s: starting channel\n", __func__);
+
+        config = readl(chan->regs + PL080S_CH_CONFIG);
+        config |= PL080_CONFIG_ENABLE;
+
+        pr_debug("%s: writing config %08x\n", __func__, config);
+        writel(config, chan->regs + PL080S_CH_CONFIG);
+
+        return 0;
+}
+
+static int s3c64xx_dma_stop(struct s3c2410_dma_chan *chan)
+{
+        u32 config;
+        int timeout;
+
+        pr_debug("%s: stopping channel\n", __func__);
+
+        dbg_showchan(chan);
+
+        config = readl(chan->regs + PL080S_CH_CONFIG);
+        config |= PL080_CONFIG_HALT;
+        writel(config, chan->regs + PL080S_CH_CONFIG);
+
+        timeout = 1000;
+        do {
+                config = readl(chan->regs + PL080S_CH_CONFIG);
+                pr_debug("%s: %d - config %08x\n", __func__, timeout, config);
+                if (config & PL080_CONFIG_ACTIVE)
+                        udelay(10);
+                else
+                        break;
+                } while (--timeout > 0);
+
+        if (config & PL080_CONFIG_ACTIVE) {
+                printk(KERN_ERR "%s: channel still active\n", __func__);
+                return -EFAULT;
+        }
+
+        config = readl(chan->regs + PL080S_CH_CONFIG);
+        config &= ~PL080_CONFIG_ENABLE;
+        writel(config, chan->regs + PL080S_CH_CONFIG);
+
+        return 0;
+}
+
+static inline void s3c64xx_dma_bufffdone(struct s3c2410_dma_chan *chan,
+                                         struct s3c64xx_dma_buff *buf,
+                                         enum s3c2410_dma_buffresult result)
+{
+        if (chan->callback_fn != NULL)
+                (chan->callback_fn)(chan, buf->pw, 0, result);
+}
+
+static void s3c64xx_dma_freebuff(struct s3c64xx_dma_buff *buff)
+{
+        dma_pool_free(dma_pool, buff->lli, buff->lli_dma);
+        kfree(buff);
+}
+
+static int s3c64xx_dma_flush(struct s3c2410_dma_chan *chan)
+{
+        struct s3c64xx_dma_buff *buff, *next;
+        u32 config;
+
+        dbg_showchan(chan);
+
+        pr_debug("%s: flushing channel\n", __func__);
+
+        config = readl(chan->regs + PL080S_CH_CONFIG);
+        config &= ~PL080_CONFIG_ENABLE;
+        writel(config, chan->regs + PL080S_CH_CONFIG);
+
+        /* dump all the buffers associated with this channel */
+
+        for (buff = chan->curr; buff != NULL; buff = next) {
+                next = buff->next;
+                pr_debug("%s: buff %p (next %p)\n", __func__, buff, buff->next);
+
+                s3c64xx_dma_bufffdone(chan, buff, S3C2410_RES_ABORT);
+                s3c64xx_dma_freebuff(buff);
+        }
+
+        chan->curr = chan->next = chan->end = NULL;
+
+        return 0;
+}
+
+int s3c2410_dma_ctrl(unsigned int channel, enum s3c2410_chan_op op)
+{
+        struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
+
+        WARN_ON(!chan);
+        if (!chan)
+                return -EINVAL;
+
+        switch (op) {
+        case S3C2410_DMAOP_START:
+                return s3c64xx_dma_start(chan);
+
+        case S3C2410_DMAOP_STOP:
+                return s3c64xx_dma_stop(chan);
+
+        case S3C2410_DMAOP_FLUSH:
+                return s3c64xx_dma_flush(chan);
+
+        /* belive PAUSE/RESUME are no-ops */
+        case S3C2410_DMAOP_PAUSE:
+        case S3C2410_DMAOP_RESUME:
+        case S3C2410_DMAOP_STARTED:
+        case S3C2410_DMAOP_TIMEOUT:
+                return 0;
+        }
+
+        return -ENOENT;
+}
+EXPORT_SYMBOL(s3c2410_dma_ctrl);
+
+/* s3c2410_dma_enque
+ *
+ */
+
+int s3c2410_dma_enqueue(unsigned int channel, void *id,
+                        dma_addr_t data, int size)
+{
+        struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
+        struct s3c64xx_dma_buff *next;
+        struct s3c64xx_dma_buff *buff;
+        struct pl080s_lli *lli;
+        int ret;
+
+        WARN_ON(!chan);
+        if (!chan)
+                return -EINVAL;
+
+        buff = kzalloc(sizeof(struct s3c64xx_dma_buff), GFP_KERNEL);
+        if (!buff) {
+                printk(KERN_ERR "%s: no memory for buffer\n", __func__);
+                return -ENOMEM;
+        }
+
+        lli = dma_pool_alloc(dma_pool, GFP_KERNEL, &buff->lli_dma);
+        if (!lli) {
+                printk(KERN_ERR "%s: no memory for lli\n", __func__);
+                ret = -ENOMEM;
+                goto err_buff;
+        }
+
+        pr_debug("%s: buff %p, dp %08x lli (%p, %08x) %d\n",
+                 __func__, buff, data, lli, (u32)buff->lli_dma, size);
+
+        buff->lli = lli;
+        buff->pw = id;
+
+        s3c64xx_dma_fill_lli(chan, lli, data, size);
+
+        if ((next = chan->next) != NULL) {
+                struct s3c64xx_dma_buff *end = chan->end;
+                struct pl080s_lli *endlli = end->lli;
+
+                pr_debug("enquing onto channel\n");
+
+                end->next = buff;
+                endlli->next_lli = buff->lli_dma;
+
+                if (chan->flags & S3C2410_DMAF_CIRCULAR) {
+                        struct s3c64xx_dma_buff *curr = chan->curr;
+                        lli->next_lli = curr->lli_dma;
+                }
+
+                if (next == chan->curr) {
+                        writel(buff->lli_dma, chan->regs + PL080_CH_LLI);
+                        chan->next = buff;
+                }
+
+                show_lli(endlli);
+                chan->end = buff;
+        } else {
+                pr_debug("enquing onto empty channel\n");
+
+                chan->curr = buff;
+                chan->next = buff;
+                chan->end = buff;
+
+                s3c64xx_lli_to_regs(chan, lli);
+        }
+
+        show_lli(lli);
+
+        dbg_showchan(chan);
+        dbg_showbuffs(chan);
+        return 0;
+
+err_buff:
+        kfree(buff);
+        return ret;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_enqueue);
+
+
+int s3c2410_dma_devconfig(int channel,
+                          enum s3c2410_dmasrc source,
+                          unsigned long devaddr)
+{
+        struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
+        u32 peripheral;
+        u32 config = 0;
+
+        printk("%s: channel %d, source %d, dev %08lx, chan %p\n",
+                 __func__, channel, source, devaddr, chan);
+
+        WARN_ON(!chan);
+        if (!chan)
+                return -EINVAL;
+
+        peripheral = (chan->peripheral & 0xf);
+        chan->source = source;
+        chan->dev_addr = devaddr;
+
+        pr_debug("%s: peripheral %d\n", __func__, peripheral);
+
+        switch (source) {
+        case S3C2410_DMASRC_HW:
+                config = 2 << PL080_CONFIG_FLOW_CONTROL_SHIFT;
+                config |= peripheral << PL080_CONFIG_SRC_SEL_SHIFT;
+                break;
+        case S3C2410_DMASRC_MEM:
+                config = 1 << PL080_CONFIG_FLOW_CONTROL_SHIFT;
+                config |= peripheral << PL080_CONFIG_DST_SEL_SHIFT;
+                break;
+        default:
+                printk(KERN_ERR "%s: bad source\n", __func__);
+                return -EINVAL;
+        }
+
+        /* allow TC and ERR interrupts */
+        config |= PL080_CONFIG_TC_IRQ_MASK;
+        config |= PL080_CONFIG_ERR_IRQ_MASK;
+
+        pr_debug("%s: config %08x\n", __func__, config);
+
+        writel(config, chan->regs + PL080S_CH_CONFIG);
+
+        return 0;
+}
+EXPORT_SYMBOL(s3c2410_dma_devconfig);
+
+
+int s3c2410_dma_getposition(unsigned int channel,
+                            dma_addr_t *src, dma_addr_t *dst)
+{
+        struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
+
+        WARN_ON(!chan);
+        if (!chan)
+                return -EINVAL;
+
+        if (src != NULL)
+                *src = readl(chan->regs + PL080_CH_SRC_ADDR);
+
+        if (dst != NULL)
+                *dst = readl(chan->regs + PL080_CH_DST_ADDR);
+
+        return 0;
+}
+EXPORT_SYMBOL(s3c2410_dma_getposition);
+
+/* s3c2410_request_dma
+ *
+ * get control of an dma channel
+*/
+
+int s3c2410_dma_request(unsigned int channel,
+                        struct s3c2410_dma_client *client,
+                        void *dev)
+{
+        struct s3c2410_dma_chan *chan;
+        unsigned long flags;
+
+        pr_debug("dma%d: s3c2410_request_dma: client=%s, dev=%p\n",
+                 channel, client->name, dev);
+
+        local_irq_save(flags);
+
+        chan = s3c64xx_dma_map_channel(channel);
+        if (chan == NULL) {
+                local_irq_restore(flags);
+                return -EBUSY;
+        }
+
+        dbg_showchan(chan);
+
+        chan->client = client;
+        chan->in_use = 1;
+        chan->peripheral = channel;
+
+        local_irq_restore(flags);
+
+        /* need to setup */
+
+        pr_debug("%s: channel initialised, %p\n", __func__, chan);
+
+        return chan->number | DMACH_LOW_LEVEL;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_request);
+
+/* s3c2410_dma_free
+ *
+ * release the given channel back to the system, will stop and flush
+ * any outstanding transfers, and ensure the channel is ready for the
+ * next claimant.
+ *
+ * Note, although a warning is currently printed if the freeing client
+ * info is not the same as the registrant's client info, the free is still
+ * allowed to go through.
+*/
+
+int s3c2410_dma_free(unsigned int channel, struct s3c2410_dma_client *client)
+{
+        struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
+        unsigned long flags;
+
+        if (chan == NULL)
+                return -EINVAL;
+
+        local_irq_save(flags);
+
+        if (chan->client != client) {
+                printk(KERN_WARNING "dma%d: possible free from different client (channel %p, passed %p)\n",
+                       channel, chan->client, client);
+        }
+
+        /* sort out stopping and freeing the channel */
+
+
+        chan->client = NULL;
+        chan->in_use = 0;
+
+        if (!(channel & DMACH_LOW_LEVEL))
+                s3c_dma_chan_map[channel] = NULL;
+
+        local_irq_restore(flags);
+
+        return 0;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_free);
+
+
+static void s3c64xx_dma_tcirq(struct s3c64xx_dmac *dmac, int offs)
+{
+        struct s3c2410_dma_chan *chan = dmac->channels + offs;
+
+        /* note, we currently do not bother to work out which buffer
+         * or buffers have been completed since the last tc-irq. */
+
+        if (chan->callback_fn)
+                (chan->callback_fn)(chan, chan->curr->pw, 0, S3C2410_RES_OK);
+}
+
+static void s3c64xx_dma_errirq(struct s3c64xx_dmac *dmac, int offs)
+{
+        printk(KERN_DEBUG "%s: offs %d\n", __func__, offs);
+}
+
+static irqreturn_t s3c64xx_dma_irq(int irq, void *pw)
+{
+        struct s3c64xx_dmac *dmac = pw;
+        u32 tcstat, errstat;
+        u32 bit;
+        int offs;
+
+        tcstat = readl(dmac->regs + PL080_TC_STATUS);
+        errstat = readl(dmac->regs + PL080_ERR_STATUS);
+
+        for (offs = 0, bit = 1; offs < 8; offs++, bit <<= 1) {
+                if (tcstat & bit) {
+                        writel(bit, dmac->regs + PL080_TC_CLEAR);
+                        s3c64xx_dma_tcirq(dmac, offs);
+                }
+
+                if (errstat & bit) {
+                        s3c64xx_dma_errirq(dmac, offs);
+                        writel(bit, dmac->regs + PL080_ERR_CLEAR);
+                }
+        }
+
+        return IRQ_HANDLED;
+}
+
+static struct sysdev_class dma_sysclass = {
+        .name           = "s3c64xx-dma",
+};
+
+static int s3c64xx_dma_init1(int chno, enum dma_ch chbase,
+                             int irq, unsigned int base)
+{
+        struct s3c2410_dma_chan *chptr = &s3c2410_chans[chno];
+        struct s3c64xx_dmac *dmac;
+        char clkname[16];
+        void __iomem *regs;
+        void __iomem *regptr;
+        int err, ch;
+
+        dmac = kzalloc(sizeof(struct s3c64xx_dmac), GFP_KERNEL);
+        if (!dmac) {
+                printk(KERN_ERR "%s: failed to alloc mem\n", __func__);
+                return -ENOMEM;
+        }
+
+        dmac->sysdev.id = chno / 8;
+        dmac->sysdev.cls = &dma_sysclass;
+
+        err = sysdev_register(&dmac->sysdev);
+        if (err) {
+                printk(KERN_ERR "%s: failed to register sysdevice\n", __func__);
+                goto err_alloc;
+        }
+
+        regs = ioremap(base, 0x200);
+        if (!regs) {
+                printk(KERN_ERR "%s: failed to ioremap()\n", __func__);
+                err = -ENXIO;
+                goto err_dev;
+        }
+
+        snprintf(clkname, sizeof(clkname), "dma%d", dmac->sysdev.id);
+
+        dmac->clk = clk_get(NULL, clkname);
+        if (IS_ERR(dmac->clk)) {
+                printk(KERN_ERR "%s: failed to get clock %s\n", __func__, clkname);
+                err = PTR_ERR(dmac->clk);
+                goto err_map;
+        }
+
+        clk_enable(dmac->clk);
+
+        dmac->regs = regs;
+        dmac->chanbase = chbase;
+        dmac->channels = chptr;
+
+        err = request_irq(irq, s3c64xx_dma_irq, 0, "DMA", dmac);
+        if (err < 0) {
+                printk(KERN_ERR "%s: failed to get irq\n", __func__);
+                goto err_clk;
+        }
+
+        regptr = regs + PL080_Cx_BASE(0);
+
+        for (ch = 0; ch < 8; ch++, chno++, chptr++) {
+                printk(KERN_INFO "%s: registering DMA %d (%p)\n",
+                       __func__, chno, regptr);
+
+                chptr->bit = 1 << ch;
+                chptr->number = chno;
+                chptr->dmac = dmac;
+                chptr->regs = regptr;
+                regptr += PL008_Cx_STRIDE;
+        }
+
+        /* for the moment, permanently enable the controller */
+        writel(PL080_CONFIG_ENABLE, regs + PL080_CONFIG);
+
+        printk(KERN_INFO "PL080: IRQ %d, at %p\n", irq, regs);
+
+        return 0;
+
+err_clk:
+        clk_disable(dmac->clk);
+        clk_put(dmac->clk);
+err_map:
+        iounmap(regs);
+err_dev:
+        sysdev_unregister(&dmac->sysdev);
+err_alloc:
+        kfree(dmac);
+        return err;
+}
+
+static int __init s3c64xx_dma_init(void)
+{
+        int ret;
+
+        printk(KERN_INFO "%s: Registering DMA channels\n", __func__);
+
+        dma_pool = dma_pool_create("DMA-LLI", NULL, 32, 16, 0);
+        if (!dma_pool) {
+                printk(KERN_ERR "%s: failed to create pool\n", __func__);
+                return -ENOMEM;
+        }
+
+        ret = sysdev_class_register(&dma_sysclass);
+        if (ret) {
+                printk(KERN_ERR "%s: failed to create sysclass\n", __func__);
+                return -ENOMEM;
+        }
+
+        /* Set all DMA configuration to be DMA, not SDMA */
+        writel(0xffffff, S3C_SYSREG(0x110));
+
+        /* Register standard DMA controlers */
+        s3c64xx_dma_init1(0, DMACH_UART0, IRQ_DMA0, 0x75000000);
+        s3c64xx_dma_init1(8, DMACH_PCM1_TX, IRQ_DMA1, 0x75100000);
+
+        return 0;
+}
+
+arch_initcall(s3c64xx_dma_init);