usb: musb: tusb6010_omap: Allocate DMA channels upfront

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>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/musb/tusb6010_omap.c b/drivers/usb/musb/tusb6010_omap.c
index c2ef8e3eb91e624a52e1d156557fa49f169c374b..f8671110168bb16a4041f446dbcbb86d00bc87be 100644 (file)
--- 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);
@@ -248,7 +245,8 @@ 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;
        }
@@ -260,11 +258,8 @@ 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;
@@ -276,10 +271,10 @@ 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;
@@ -410,19 +405,9 @@ 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;
 
@@ -434,15 +419,6 @@ 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) {
@@ -459,8 +435,7 @@ 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;
 }
@@ -469,15 +444,14 @@ 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];
@@ -488,8 +462,6 @@ 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;
@@ -543,46 +515,22 @@ 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;
@@ -604,7 +552,7 @@ 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)
@@ -622,14 +570,8 @@ 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;
 }
@@ -646,15 +588,73 @@ 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)
 {
@@ -679,10 +679,6 @@ 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;
@@ -709,6 +705,9 @@ 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: