[PATCH 11/14] dmaengine: ti: omap-dma: Allocate channels directly

Tony Lindgren
2019-12-17T00:23:11Z

With the legacy IRQ handling gone, we can now start allocating channels
directly in the dmaengine driver for device tree based SoCs.

Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
drivers/dma/ti/omap-dma.c | 62 ++++++++++++++++++++++++++++++++++++---
1 file changed, 58 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c
--- a/drivers/dma/ti/omap-dma.c
+++ b/drivers/dma/ti/omap-dma.c
@@ -28,6 +28,7 @@ struct omap_dma_config {
int lch_end;
unsigned int rw_priority:1;
unsigned int may_lose_context:1;
+ unsigned int needs_lch_clear:1;
};

struct omap_dma_context {
@@ -47,6 +48,8 @@ struct omap_dmadev {
struct notifier_block nb;
struct omap_dma_context context;
int lch_count;
+ DECLARE_BITMAP(lch_bitmap, OMAP_SDMA_CHANNELS);
+ struct mutex lch_lock; /* for assigning logical channels */
bool legacy;
bool ll123_supported;
struct dma_pool *desc_pool;
@@ -664,6 +667,37 @@ static irqreturn_t omap_dma_irq(int irq, void *devid)
return IRQ_HANDLED;
}

+static int omap_dma_get_lch(struct omap_dmadev *od, int *lch)
+{
+ int channel;
+
+ mutex_lock(&od->lch_lock);
+ channel = find_first_zero_bit(od->lch_bitmap, od->lch_count);
+ if (channel >= od->lch_count)
+ goto out_busy;
+ set_bit(channel, od->lch_bitmap);
+ mutex_unlock(&od->lch_lock);
+
+ omap_dma_clear_lch(od, channel);
+ *lch = channel;
+
+ return 0;
+
+out_busy:
+ mutex_unlock(&od->lch_lock);
+ *lch = -EINVAL;
+
+ return -EBUSY;
+}
+
+static void omap_dma_put_lch(struct omap_dmadev *od, int lch)
+{
+ omap_dma_clear_lch(od, lch);
+ mutex_lock(&od->lch_lock);
+ clear_bit(lch, od->lch_bitmap);
+ mutex_unlock(&od->lch_lock);
+}
+
static int omap_dma_alloc_chan_resources(struct dma_chan *chan)
{
struct omap_dmadev *od = to_omap_dma_dev(chan->device);
@@ -675,15 +709,13 @@ static int omap_dma_alloc_chan_resources(struct dma_chan *chan)
ret = omap_request_dma(c->dma_sig, "DMA engine",
omap_dma_callback, c, &c->dma_ch);
} else {
- ret = omap_request_dma(c->dma_sig, "DMA engine", NULL, NULL,
- &c->dma_ch);
+ ret = omap_dma_get_lch(od, &c->dma_ch);
}

dev_dbg(dev, "allocating channel %u for %u\n", c->dma_ch, c->dma_sig);

if (ret >= 0) {
omap_dma_assign(od, c, c->dma_ch);
- pr_info("XXX %s: assigned lch: %i\n", __func__, c->dma_ch);

if (!od->legacy) {
unsigned val;
@@ -734,7 +766,11 @@ static void omap_dma_free_chan_resources(struct dma_chan *chan)
c->channel_base = NULL;
od->lch_map[c->dma_ch] = NULL;
vchan_free_chan_resources(&c->vc);
- omap_free_dma(c->dma_ch);
+
+ if (od->legacy)
+ omap_free_dma(c->dma_ch);
+ else
+ omap_dma_put_lch(od, c->dma_ch);

dev_dbg(od->ddev.dev, "freeing channel %u used for %u\n", c->dma_ch,
c->dma_sig);
@@ -1574,6 +1610,7 @@ static int omap_dma_probe(struct platform_device *pdev)
struct omap_dmadev *od;
struct resource *res;
int rc, i, irq;
+ u32 val;

od = devm_kzalloc(&pdev->dev, sizeof(*od), GFP_KERNEL);
if (!od)
@@ -1628,6 +1665,7 @@ static int omap_dma_probe(struct platform_device *pdev)
od->ddev.max_burst = SZ_16M - 1; /* CCEN: 24bit unsigned */
od->ddev.dev = &pdev->dev;
INIT_LIST_HEAD(&od->ddev.channels);
+ mutex_init(&od->lch_lock);
spin_lock_init(&od->lock);
spin_lock_init(&od->irq_lock);

@@ -1654,6 +1692,17 @@ static int omap_dma_probe(struct platform_device *pdev)
od->lch_count = OMAP_SDMA_CHANNELS;
}

+ /* Mask of allowed logical channels */
+ if (pdev->dev.of_node && !of_property_read_u32(pdev->dev.of_node,
+ "dma-channel-mask",
+ &val)) {
+ /* Tag channels not in mask as reserved */
+ val = ~val;
+ bitmap_from_arr32(od->lch_bitmap, &val, od->lch_count);
+ }
+ if (od->plat->dma_attr->dev_caps & HS_CHANNELS_RESERVED)
+ bitmap_set(od->lch_bitmap, 0, 2);
+
od->lch_map = devm_kcalloc(&pdev->dev, od->lch_count,
sizeof(*od->lch_map),
GFP_KERNEL);
@@ -1772,28 +1821,33 @@ static int omap_dma_remove(struct platform_device *pdev)
static const struct omap_dma_config omap2420_data = {
.lch_end = CCFN,
.rw_priority = true,
+ .needs_lch_clear = true,
};

static const struct omap_dma_config omap2430_data = {
.lch_end = CCFN,
.rw_priority = true,
+ .needs_lch_clear = true,
};

static const struct omap_dma_config omap3430_data = {
.lch_end = CCFN,
.rw_priority = true,
+ .needs_lch_clear = true,
.may_lose_context = true,
};

static const struct omap_dma_config omap3630_data = {
.lch_end = CCDN,
.rw_priority = true,
+ .needs_lch_clear = true,
.may_lose_context = true,
};

static const struct omap_dma_config omap4_data = {
.lch_end = CCDN,
.rw_priority = true,
+ .needs_lch_clear = true,
};

static const struct of_device_id omap_dma_match[] = {