[PATCH v2 07/10] usb: musb: tusb6010_omap: Allocate DMA channels upfront

Peter Ujfalusi
2017-05-10T08:43:10Z

Instead of requesting the DMA channel in tusb_omap_dma_allocate() do it
when the controller is created and in runtime work from the DMA channel
pool.

This change is needed for the DMAengine conversion of the driver since the
tusb_omap_dma_allocate() is called in interrupt context which might lead
to lock within the DMAengine API when requesting channel.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
drivers/usb/musb/tusb6010_omap.c | 184 +++++++++++++++++++--------------------
1 file changed, 92 insertions(+), 92 deletions(-)

diff --git a/drivers/usb/musb/tusb6010_omap.c b/drivers/usb/musb/tusb6010_omap.c
index f1e58e15e5bb..2daeef7e572d 100644
--- a/drivers/usb/musb/tusb6010_omap.c
+++ b/drivers/usb/musb/tusb6010_omap.c
@@ -45,7 +45,7 @@ struct tusb_omap_dma_ch {
u8 tx;
struct musb_hw_ep *hw_ep;

- struct tusb_dma_data dma_data;
+ struct tusb_dma_data *dma_data;

struct tusb_omap_dma *tusb_dma;

@@ -62,7 +62,7 @@ struct tusb_omap_dma {
struct dma_controller controller;
void __iomem *tbase;

- struct tusb_dma_data dma_data;
+ struct tusb_dma_data dma_pool[MAX_DMAREQ];
unsigned multichannel:1;
};

@@ -120,10 +120,7 @@ static void tusb_omap_dma_cb(int lch, u16 ch_status, void *data)

spin_lock_irqsave(&musb->lock, flags);

- if (tusb_dma->multichannel)
- ch = chdat->dma_data.ch;
- else
- ch = tusb_dma->dma_data.ch;
+ ch = chdat->dma_data->ch;

if (ch_status != OMAP_DMA_BLOCK_IRQ)
printk(KERN_ERR "TUSB DMA error status: %i\n", ch_status);
@@ -247,7 +244,8 @@ static int tusb_omap_dma_program(struct dma_channel *channel, u16 packet_sz,
dma_remaining = TUSB_EP_CONFIG_XFR_SIZE(dma_remaining);
if (dma_remaining) {
dev_dbg(musb->controller, "Busy %s dma ch%i, not using: %08x\n",
- chdat->tx ? "tx" : "rx", chdat->dma_data.ch,
+ chdat->tx ? "tx" : "rx",
+ chdat->dma_data ? chdat->dma_data->ch : -1,
dma_remaining);
return false;
}
@@ -259,11 +257,8 @@ static int tusb_omap_dma_program(struct dma_channel *channel, u16 packet_sz,
else
chdat->transfer_packet_sz = packet_sz;

- if (tusb_dma->multichannel) {
- dma_data = &chdat->dma_data;
- } else {
- dma_data = &tusb_dma->dma_data;
-
+ dma_data = chdat->dma_data;
+ if (!tusb_dma->multichannel) {
if (tusb_omap_use_shared_dmareq(chdat) != 0) {
dev_dbg(musb->controller, "could not get dma for ep%i\n", chdat->epnum);
return false;
@@ -275,10 +270,10 @@ static int tusb_omap_dma_program(struct dma_channel *channel, u16 packet_sz,
WARN_ON(1);
return false;
}
-
- omap_set_dma_callback(dma_data->ch, tusb_omap_dma_cb, channel);
}

+ omap_set_dma_callback(dma_data->ch, tusb_omap_dma_cb, channel);
+
chdat->packet_sz = packet_sz;
chdat->len = len;
channel->actual_len = 0;
@@ -409,19 +404,9 @@ static int tusb_omap_dma_program(struct dma_channel *channel, u16 packet_sz,
static int tusb_omap_dma_abort(struct dma_channel *channel)
{
struct tusb_omap_dma_ch *chdat = to_chdat(channel);
- struct tusb_omap_dma *tusb_dma = chdat->tusb_dma;
- struct tusb_dma_data *dma_data = &tusb_dma->dma_data;

- if (!tusb_dma->multichannel) {
- if (dma_data->ch >= 0) {
- omap_stop_dma(dma_data->ch);
- omap_free_dma(dma_data->ch);
- dma_data->ch = -1;
- }
-
- dma_data->dmareq = -1;
- dma_data->sync_dev = -1;
- }
+ if (chdat->dma_data)
+ omap_stop_dma(chdat->dma_data->ch);

channel->status = MUSB_DMA_STATUS_FREE;

@@ -433,15 +418,6 @@ static inline int tusb_omap_dma_allocate_dmareq(struct tusb_omap_dma_ch *chdat)
u32 reg = musb_readl(chdat->tbase, TUSB_DMA_EP_MAP);
int i, dmareq_nr = -1;

- const int sync_dev[6] = {
- OMAP24XX_DMA_EXT_DMAREQ0,
- OMAP24XX_DMA_EXT_DMAREQ1,
- OMAP242X_DMA_EXT_DMAREQ2,
- OMAP242X_DMA_EXT_DMAREQ3,
- OMAP242X_DMA_EXT_DMAREQ4,
- OMAP242X_DMA_EXT_DMAREQ5,
- };
-
for (i = 0; i < MAX_DMAREQ; i++) {
int cur = (reg & (0xf << (i * 5))) >> (i * 5);
if (cur == 0) {
@@ -458,8 +434,7 @@ static inline int tusb_omap_dma_allocate_dmareq(struct tusb_omap_dma_ch *chdat)
reg |= ((1 << 4) << (dmareq_nr * 5));
musb_writel(chdat->tbase, TUSB_DMA_EP_MAP, reg);

- chdat->dma_data.dmareq = dmareq_nr;
- chdat->dma_data.sync_dev = sync_dev[chdat->dma_data.dmareq];
+ chdat->dma_data = &chdat->tusb_dma->dma_pool[dmareq_nr];

return 0;
}
@@ -468,15 +443,14 @@ static inline void tusb_omap_dma_free_dmareq(struct tusb_omap_dma_ch *chdat)
{
u32 reg;

- if (!chdat || chdat->dma_data.dmareq < 0)
+ if (!chdat || !chdat->dma_data || chdat->dma_data->dmareq < 0)
return;

reg = musb_readl(chdat->tbase, TUSB_DMA_EP_MAP);
- reg &= ~(0x1f << (chdat->dma_data.dmareq * 5));
+ reg &= ~(0x1f << (chdat->dma_data->dmareq * 5));
musb_writel(chdat->tbase, TUSB_DMA_EP_MAP, reg);

- chdat->dma_data.dmareq = -1;
- chdat->dma_data.sync_dev = -1;
+ chdat->dma_data = NULL;
}

static struct dma_channel *dma_channel_pool[MAX_DMAREQ];
@@ -487,8 +461,6 @@ tusb_omap_dma_allocate(struct dma_controller *c,
u8 tx)
{
int ret, i;
- const char *dev_name;
- void *cb_data;
struct tusb_omap_dma *tusb_dma;
struct musb *musb;
void __iomem *tbase;
@@ -542,45 +514,22 @@ tusb_omap_dma_allocate(struct dma_controller *c,
channel->desired_mode = 0;
channel->actual_len = 0;

- if (tusb_dma->multichannel) {
- dma_data = &chdat->dma_data;
- ret = tusb_omap_dma_allocate_dmareq(chdat);
- if (ret != 0)
- goto free_dmareq;
-
- if (chdat->tx)
- dev_name = "TUSB transmit";
- else
- dev_name = "TUSB receive";
- cb_data = channel;
- } else if (tusb_dma->dma_data.ch == -1) {
- dma_data = &tusb_dma->dma_data;
- dma_data->dmareq = 0;
- dma_data->sync_dev = OMAP24XX_DMA_EXT_DMAREQ0;
-
- dev_name = "TUSB shared";
- /* Callback data gets set later in the shared dmareq case */
- cb_data = NULL;
-
- chdat->dma_data.dmareq = -1;
- chdat->dma_data.ch = -1;
- chdat->dma_data.sync_dev = -1;
+ if (!chdat->dma_data) {
+ if (tusb_dma->multichannel) {
+ ret = tusb_omap_dma_allocate_dmareq(chdat);
+ if (ret != 0)
+ goto free_dmareq;
+ } else {
+ chdat->dma_data = &tusb_dma->dma_pool[0];
+ }
}

- if (dma_data) {
- ret = omap_request_dma(dma_data->sync_dev, dev_name,
- tusb_omap_dma_cb, cb_data, &dma_data->ch);
- if (ret != 0)
- goto free_dmareq;
- } else {
- /* Already allocated shared, single DMA channel. */
- dma_data = &tusb_dma->dma_data;
- }
+ dma_data = chdat->dma_data;

dev_dbg(musb->controller, "ep%i %s dma: %s dma%i dmareq%i sync%i\n",
chdat->epnum,
chdat->tx ? "tx" : "rx",
- chdat->dma_data.ch >= 0 ? "dedicated" : "shared",
+ tusb_dma->multichannel ? "shared" : "dedicated",
dma_data->ch, dma_data->dmareq, dma_data->sync_dev);

return channel;
@@ -602,7 +551,7 @@ static void tusb_omap_dma_release(struct dma_channel *channel)
u32 reg;

dev_dbg(musb->controller, "ep%i ch%i\n", chdat->epnum,
- chdat->dma_data.ch);
+ chdat->dma_data->ch);

reg = musb_readl(tbase, TUSB_DMA_INT_MASK);
if (chdat->tx)
@@ -620,14 +569,8 @@ static void tusb_omap_dma_release(struct dma_channel *channel)

channel->status = MUSB_DMA_STATUS_UNKNOWN;

- if (chdat->dma_data.ch >= 0) {
- omap_stop_dma(chdat->dma_data.ch);
- omap_free_dma(chdat->dma_data.ch);
- chdat->dma_data.ch = -1;
- }
-
- if (chdat->dma_data.dmareq >= 0)
- tusb_omap_dma_free_dmareq(chdat);
+ omap_stop_dma(chdat->dma_data->ch);
+ tusb_omap_dma_free_dmareq(chdat);

channel = NULL;
}
@@ -644,15 +587,73 @@ void tusb_dma_controller_destroy(struct dma_controller *c)
kfree(ch->private_data);
kfree(ch);
}
- }

- if (tusb_dma && !tusb_dma->multichannel && tusb_dma->dma_data.ch >= 0)
- omap_free_dma(tusb_dma->dma_data.ch);
+ /* Free up the DMA channels */
+ if (tusb_dma && tusb_dma->dma_pool[i].ch >= 0)
+ omap_free_dma(tusb_dma->dma_pool[i].ch);
+ }

kfree(tusb_dma);
}
EXPORT_SYMBOL_GPL(tusb_dma_controller_destroy);

+static int tusb_omap_allocate_dma_pool(struct tusb_omap_dma *tusb_dma)
+{
+ int i;
+ int ret = 0;
+ const int sync_dev[6] = {
+ OMAP24XX_DMA_EXT_DMAREQ0,
+ OMAP24XX_DMA_EXT_DMAREQ1,
+ OMAP242X_DMA_EXT_DMAREQ2,
+ OMAP242X_DMA_EXT_DMAREQ3,
+ OMAP242X_DMA_EXT_DMAREQ4,
+ OMAP242X_DMA_EXT_DMAREQ5,
+ };
+
+ for (i = 0; i < MAX_DMAREQ; i++) {
+ struct tusb_dma_data *dma_data = &tusb_dma->dma_pool[i];
+
+ /*
+ * Request DMA channels:
+ * - one channel in case of non multichannel mode
+ * - MAX_DMAREQ number of channels in multichannel mode
+ */
+ if (i == 0 || tusb_dma->multichannel) {
+ char ch_name[8];
+
+ sprintf(ch_name, "dmareq%d", i);
+ dma_data->sync_dev = sync_dev[i];
+ dma_data->ch = -1;
+ /* callback data is ngoing to be set later */
+ ret = omap_request_dma(dma_data->sync_dev, ch_name,
+ tusb_omap_dma_cb, NULL, &dma_data->ch);
+ if (ret != 0) {
+ dev_err(tusb_dma->controller.musb->controller,
+ "Failed to request %s\n", ch_name);
+ goto dma_error;
+ }
+
+ dma_data->dmareq = i;
+ } else {
+ dma_data->dmareq = -1;
+ dma_data->sync_dev = -1;
+ dma_data->ch = -1;
+ }
+ }
+
+ return 0;
+
+dma_error:
+ for (; i >= 0; i--) {
+ struct tusb_dma_data *dma_data = &tusb_dma->dma_pool[i];
+
+ if (dma_data->ch >= 0)
+ omap_free_dma(dma_data->ch);
+ }
+
+ return ret;
+}
+
struct dma_controller *
tusb_dma_controller_create(struct musb *musb, void __iomem *base)
{
@@ -677,10 +678,6 @@ tusb_dma_controller_create(struct musb *musb, void __iomem *base)
tusb_dma->controller.musb = musb;
tusb_dma->tbase = musb->ctrl_base;

- tusb_dma->dma_data.ch = -1;
- tusb_dma->dma_data.dmareq = -1;
- tusb_dma->dma_data.sync_dev = -1;
-
tusb_dma->controller.channel_alloc = tusb_omap_dma_allocate;
tusb_dma->controller.channel_release = tusb_omap_dma_release;
tusb_dma->controller.channel_program = tusb_omap_dma_program;
@@ -707,6 +704,9 @@ tusb_dma_controller_create(struct musb *musb, void __iomem *base)
ch->private_data = chdat;
}

+ if (tusb_omap_allocate_dma_pool(tusb_dma))
+ goto cleanup;
+
return &tusb_dma->controller;

cleanup:
--
2.12.2