net: ethernet: ti: cpdma: switch to use genalloc

TI CPDMA currently uses a bitmap for tracking descriptors alloactions
allocations, but The genalloc already handles the same and can be used
as with special memory (SRAM) as with DMA cherent memory chank
(dma_alloc_coherent()). Hence, switch to using genalloc and add
desc_num property for each channel for limitation of max number of
allowed descriptors for each CPDMA channel. This patch do not affect
on net throuput.

Acked-by: Mugunthan V N <mugunthanvnm@ti.com>
Tested-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c
index bcd9e45..1c653ca 100644 (file)
--- a/drivers/net/ethernet/ti/davinci_cpdma.c
+++ b/drivers/net/ethernet/ti/davinci_cpdma.c
@@ -21,7 +21,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/io.h>
 #include <linux/delay.h>
-
+#include <linux/genalloc.h>
 #include "davinci_cpdma.h"
 
 /* DMA Registers */
@@ -87,9 +87,8 @@ struct cpdma_desc_pool {
        void                    *cpumap;        /* dma_alloc map */
        int                     desc_size, mem_size;
        int                     num_desc, used_desc;
-       unsigned long           *bitmap;
        struct device           *dev;
-       spinlock_t              lock;
+       struct gen_pool         *gen_pool;
 };
 
 enum cpdma_state {
@@ -117,6 +116,7 @@ struct cpdma_chan {
        int                             chan_num;
        spinlock_t                      lock;
        int                             count;
+       u32                             desc_num;
        u32                             mask;
        cpdma_handler_fn                handler;
        enum dma_data_direction         dir;
@@ -145,6 +145,19 @@ struct cpdma_chan {
                                 (directed << CPDMA_TO_PORT_SHIFT));    \
        } while (0)
 
+static void cpdma_desc_pool_destroy(struct cpdma_desc_pool *pool)
+{
+       if (!pool)
+               return;
+
+       WARN_ON(pool->used_desc);
+       if (pool->cpumap)
+               dma_free_coherent(pool->dev, pool->mem_size, pool->cpumap,
+                                 pool->phys);
+       else
+               iounmap(pool->iomap);
+}
+
 /*
  * Utility constructs for a cpdma descriptor pool.  Some devices (e.g. davinci
  * emac) have dedicated on-chip memory for these descriptors.  Some other
@@ -155,24 +168,25 @@ static struct cpdma_desc_pool *
 cpdma_desc_pool_create(struct device *dev, u32 phys, dma_addr_t hw_addr,
                                int size, int align)
 {
-       int bitmap_size;
        struct cpdma_desc_pool *pool;
+       int ret;
 
        pool = devm_kzalloc(dev, sizeof(*pool), GFP_KERNEL);
        if (!pool)
-               goto fail;
-
-       spin_lock_init(&pool->lock);
+               goto gen_pool_create_fail;
 
        pool->dev       = dev;
        pool->mem_size  = size;
        pool->desc_size = ALIGN(sizeof(struct cpdma_desc), align);
        pool->num_desc  = size / pool->desc_size;
 
-       bitmap_size  = (pool->num_desc / BITS_PER_LONG) * sizeof(long);
-       pool->bitmap = devm_kzalloc(dev, bitmap_size, GFP_KERNEL);
-       if (!pool->bitmap)
-               goto fail;
+       pool->gen_pool = devm_gen_pool_create(dev, ilog2(pool->desc_size), -1,
+                                             "cpdma");
+       if (IS_ERR(pool->gen_pool)) {
+               dev_err(dev, "pool create failed %ld\n",
+                       PTR_ERR(pool->gen_pool));
+               goto gen_pool_create_fail;
+       }
 
        if (phys) {
                pool->phys  = phys;
@@ -185,24 +199,22 @@ cpdma_desc_pool_create(struct device *dev, u32 phys, dma_addr_t hw_addr,
                pool->phys = pool->hw_addr; /* assumes no IOMMU, don't use this value */
        }
 
-       if (pool->iomap)
-               return pool;
-fail:
-       return NULL;
-}
+       if (!pool->iomap)
+               goto gen_pool_create_fail;
 
-static void cpdma_desc_pool_destroy(struct cpdma_desc_pool *pool)
-{
-       if (!pool)
-               return;
-
-       WARN_ON(pool->used_desc);
-       if (pool->cpumap) {
-               dma_free_coherent(pool->dev, pool->mem_size, pool->cpumap,
-                                 pool->phys);
-       } else {
-               iounmap(pool->iomap);
+       ret = gen_pool_add_virt(pool->gen_pool, (unsigned long)pool->iomap,
+                               pool->phys, pool->mem_size, -1);
+       if (ret < 0) {
+               dev_err(dev, "pool add failed %d\n", ret);
+               goto gen_pool_add_virt_fail;
        }
+
+       return pool;
+
+gen_pool_add_virt_fail:
+       cpdma_desc_pool_destroy(pool);
+gen_pool_create_fail:
+       return NULL;
 }
 
 static inline dma_addr_t desc_phys(struct cpdma_desc_pool *pool,
@@ -220,47 +232,23 @@ desc_from_phys(struct cpdma_desc_pool *pool, dma_addr_t dma)
 }
 
 static struct cpdma_desc __iomem *
-cpdma_desc_alloc(struct cpdma_desc_pool *pool, int num_desc, bool is_rx)
+cpdma_desc_alloc(struct cpdma_desc_pool *pool)
 {
-       unsigned long flags;
-       int index;
-       int desc_start;
-       int desc_end;
        struct cpdma_desc __iomem *desc = NULL;
 
-       spin_lock_irqsave(&pool->lock, flags);
-
-       if (is_rx) {
-               desc_start = 0;
-               desc_end = pool->num_desc/2;
-        } else {
-               desc_start = pool->num_desc/2;
-               desc_end = pool->num_desc;
-       }
-
-       index = bitmap_find_next_zero_area(pool->bitmap,
-                               desc_end, desc_start, num_desc, 0);
-       if (index < desc_end) {
-               bitmap_set(pool->bitmap, index, num_desc);
-               desc = pool->iomap + pool->desc_size * index;
+       desc = (struct cpdma_desc __iomem *)gen_pool_alloc(pool->gen_pool,
+                                                          pool->desc_size);
+       if (desc)
                pool->used_desc++;
-       }
 
-       spin_unlock_irqrestore(&pool->lock, flags);
        return desc;
 }
 
 static void cpdma_desc_free(struct cpdma_desc_pool *pool,
                            struct cpdma_desc __iomem *desc, int num_desc)
 {
-       unsigned long flags, index;
-
-       index = ((unsigned long)desc - (unsigned long)pool->iomap) /
-               pool->desc_size;
-       spin_lock_irqsave(&pool->lock, flags);
-       bitmap_clear(pool->bitmap, index, num_desc);
+       gen_pool_free(pool->gen_pool, (unsigned long)desc, pool->desc_size);
        pool->used_desc--;
-       spin_unlock_irqrestore(&pool->lock, flags);
 }
 
 struct cpdma_ctlr *cpdma_ctlr_create(struct cpdma_params *params)
@@ -516,6 +504,7 @@ struct cpdma_chan *cpdma_chan_create(struct cpdma_ctlr *ctlr, int chan_num,
        chan->state     = CPDMA_STATE_IDLE;
        chan->chan_num  = chan_num;
        chan->handler   = handler;
+       chan->desc_num = ctlr->pool->num_desc / 2;
 
        if (is_rx_chan(chan)) {
                chan->hdp       = ctlr->params.rxhdp + offset;
@@ -681,7 +670,13 @@ int cpdma_chan_submit(struct cpdma_chan *chan, void *token, void *data,
                goto unlock_ret;
        }
 
-       desc = cpdma_desc_alloc(ctlr->pool, 1, is_rx_chan(chan));
+       if (chan->count >= chan->desc_num)      {
+               chan->stats.desc_alloc_fail++;
+               ret = -ENOMEM;
+               goto unlock_ret;
+       }
+
+       desc = cpdma_desc_alloc(ctlr->pool);
        if (!desc) {
                chan->stats.desc_alloc_fail++;
                ret = -ENOMEM;
@@ -727,24 +722,16 @@ EXPORT_SYMBOL_GPL(cpdma_chan_submit);
 
 bool cpdma_check_free_tx_desc(struct cpdma_chan *chan)
 {
-       unsigned long flags;
-       int index;
-       bool ret;
        struct cpdma_ctlr       *ctlr = chan->ctlr;
        struct cpdma_desc_pool  *pool = ctlr->pool;
+       bool                    free_tx_desc;
+       unsigned long           flags;
 
-       spin_lock_irqsave(&pool->lock, flags);
-
-       index = bitmap_find_next_zero_area(pool->bitmap,
-                               pool->num_desc, pool->num_desc/2, 1, 0);
-
-       if (index < pool->num_desc)
-               ret = true;
-       else
-               ret = false;
-
-       spin_unlock_irqrestore(&pool->lock, flags);
-       return ret;
+       spin_lock_irqsave(&chan->lock, flags);
+       free_tx_desc = (chan->count < chan->desc_num) &&
+                        gen_pool_avail(pool->gen_pool);
+       spin_unlock_irqrestore(&chan->lock, flags);
+       return free_tx_desc;
 }
 EXPORT_SYMBOL_GPL(cpdma_check_free_tx_desc);