Re: [PATCH v7 1/3] dmaengine: Add support for APM X-Gene SoC DMA engine driver

[Rameshwar Sahu]

Hi Vinod,

On Mon, Mar 16, 2015 at 2:57 PM, Vinod Koul <vinod.koul@xxxxxxxxx> wrote:
> On Thu, Mar 12, 2015 at 04:45:19PM +0530, Rameshwar Prasad Sahu wrote:
>> +/* DMA ring csr registers and bit definations */
>> +#define DMA_RING_CONFIG                      0x04
>> +#define DMA_RING_ENABLE                      BIT(31)
>> +#define DMA_RING_ID                  0x08
>> +#define DMA_RING_ID_SETUP(v)         ((v) | BIT(31))
>> +#define DMA_RING_ID_BUF                      0x0C
>> +#define DMA_RING_ID_BUF_SETUP(v)     (((v) << 9) | BIT(21))
>> +#define DMA_RING_THRESLD0_SET1               0x30
>> +#define DMA_RING_THRESLD0_SET1_VAL   0X64
>> +#define DMA_RING_THRESLD1_SET1               0x34
>> +#define DMA_RING_THRESLD1_SET1_VAL   0xC8
>> +#define DMA_RING_HYSTERESIS          0x68
>> +#define DMA_RING_HYSTERESIS_VAL              0xFFFFFFFF
>> +#define DMA_RING_STATE                       0x6C
>> +#define DMA_RING_STATE_WR_BASE               0x70
>> +#define DMA_RING_NE_INT_MODE         0x017C
>> +#define DMA_RING_NE_INT_MODE_SET(m, v)               \
>> +     ((m) = ((m) & ~BIT(31 - (v))) | BIT(31 - (v)))
>> +#define DMA_RING_NE_INT_MODE_RESET(m, v)     \
>> +     ((m) &= (~BIT(31 - (v))))
>> +#define DMA_RING_CLKEN                       0xC208
>> +#define DMA_RING_SRST                        0xC200
>> +#define DMA_RING_MEM_RAM_SHUTDOWN    0xD070
>> +#define DMA_RING_BLK_MEM_RDY         0xD074
>> +#define DMA_RING_BLK_MEM_RDY_VAL     0xFFFFFFFF
>> +#define DMA_RING_DESC_CNT(v)         (((v) & 0x0001FFFE) >> 1)
>> +#define DMA_RING_ID_GET(owner, num)  (((owner) << 6) | (num))
>> +#define DMA_RING_DST_ID(v)           ((1 << 10) | (v))
>> +#define DMA_RING_CMD_OFFSET          0x2C
>> +#define DMA_RING_CMD_BASE_OFFSET(v)  ((v) << 6)
>> +#define DMA_RING_COHERENT_SET(m)     (((u32 *)(m))[2] |= BIT(4))
>> +#define DMA_RING_ADDRL_SET(m, v)     (((u32 *)(m))[2] |= (((v) >> 8) << 5))
>> +#define DMA_RING_ADDRH_SET(m, v)     (((u32 *)(m))[3] |= ((v) >> 35))
>> +#define DMA_RING_ACCEPTLERR_SET(m)   (((u32 *)(m))[3] |= BIT(19))
>> +#define DMA_RING_SIZE_SET(m, v)              (((u32 *)(m))[3] |= ((v) << 23))
>> +#define DMA_RING_RECOMBBUF_SET(m)    (((u32 *)(m))[3] |= BIT(27))
>> +#define DMA_RING_RECOMTIMEOUTL_SET(m)        (((u32 *)(m))[3] |= (0x7 << 28))
>> +#define DMA_RING_RECOMTIMEOUTH_SET(m)        (((u32 *)(m))[4] |= 0x3)
>> +#define DMA_RING_SELTHRSH_SET(m)     (((u32 *)(m))[4] |= BIT(3))
>> +#define DMA_RING_TYPE_SET(m, v)              (((u32 *)(m))[4] |= ((v) << 19))
> These are very generic name as can conflicts, can you please namespace
> these...
>
>> +/* DMA device csr registers and bit definitions */
>> +#define DMA_IPBRR                    0x0
>> +#define DMA_DEV_ID_RD(v)             ((v) & 0x00000FFF)
>> +#define DMA_BUS_ID_RD(v)             (((v) >> 12) & 3)
>> +#define DMA_REV_NO_RD(v)             (((v) >> 14) & 3)
>> +#define DMA_GCR                              0x10
>> +#define DMA_CH_SETUP(v)                      ((v) = ((v) & ~0x000FFFFF) | 0x000AAFFF)
>> +#define DMA_ENABLE(v)                        ((v) |= BIT(31))
>> +#define DMA_DISABLE(v)                       ((v) &= ~BIT(31))
>> +#define DMA_RAID6_CONT                       0x14
>> +#define DMA_RAID6_MULTI_CTRL(v)              ((v) << 24)
>> +#define DMA_INT                              0x70
>> +#define DMA_INT_MASK                 0x74
>> +#define DMA_INT_ALL_MASK             0xFFFFFFFF
>> +#define DMA_INT_ALL_UNMASK           0x0
>> +#define DMA_INT_MASK_SHIFT           0x14
>> +#define DMA_RING_INT0_MASK           0x90A0
>> +#define DMA_RING_INT1_MASK           0x90A8
>> +#define DMA_RING_INT2_MASK           0x90B0
>> +#define DMA_RING_INT3_MASK           0x90B8
>> +#define DMA_RING_INT4_MASK           0x90C0
>> +#define DMA_CFG_RING_WQ_ASSOC                0x90E0
>> +#define DMA_ASSOC_RING_MNGR1         0xFFFFFFFF
>> +#define DMA_MEM_RAM_SHUTDOWN         0xD070
>> +#define DMA_BLK_MEM_RDY                      0xD074
>> +#define DMA_BLK_MEM_RDY_VAL          0xFFFFFFFF
> same here and throughout the driver..
>
>> +static void xgene_dma_free_descriptor(struct xgene_dma_chan *chan,
>> +                                   struct xgene_dma_desc_sw *desc)
>> +{
>> +     list_del(&desc->node);
>> +     chan_dbg(chan, "LD %p free\n", desc);
>> +     dma_pool_free(chan->desc_pool, desc, desc->tx.phys);
> where is the descriptor freed? Perhpas we can say clean rather than free
> here to not confuse...
>
>> +}
>> +
>> +static struct xgene_dma_desc_sw *xgene_dma_alloc_descriptor(
>> +                              struct xgene_dma_chan *chan)
>> +{
>> +     struct xgene_dma_desc_sw *desc;
>> +     dma_addr_t phys;
>> +
>> +     desc = dma_pool_alloc(chan->desc_pool, GFP_NOWAIT, &phys);
>> +     if (!desc) {
>> +             chan_dbg(chan, "Failed to allocate LDs\n");
> not error?
>
>> +static void xgene_dma_free_desc_list_reverse(struct xgene_dma_chan *chan,
>> +                                          struct list_head *list)
> do we really care about free order?
>
>> +{
>> +     struct xgene_dma_desc_sw *desc, *_desc;
>> +
>> +     list_for_each_entry_safe_reverse(desc, _desc, list, node)
>> +             xgene_dma_free_descriptor(chan, desc);
>> +}
>> +
>> +static void xgene_dma_free_chan_resources(struct dma_chan *dchan)
>> +{
>> +     struct xgene_dma_chan *chan = to_dma_chan(dchan);
>> +
>> +     chan_dbg(chan, "Free all resources\n");
>> +
>> +     if (!chan->desc_pool)
>> +             return;
>> +
>> +     spin_lock_bh(&chan->lock);
>> +
>> +     /* Process all running descriptor */
>> +     xgene_dma_cleanup_descriptors(chan);
>> +
>> +     /* Clean all link descriptor queues */
>> +     xgene_dma_free_desc_list(chan, &chan->ld_pending);
>> +     xgene_dma_free_desc_list(chan, &chan->ld_running);
>> +     xgene_dma_free_desc_list(chan, &chan->ld_completed);
>> +
>> +     spin_unlock_bh(&chan->lock);
>> +
>> +     /* Delete this channel DMA pool */
>> +     dma_pool_destroy(chan->desc_pool);
>> +     chan->desc_pool = NULL;
>> +}
>> +
>> +static struct dma_async_tx_descriptor *xgene_dma_prep_memcpy(
>> +     struct dma_chan *dchan, dma_addr_t dst, dma_addr_t src,
>> +     size_t len, unsigned long flags)
>> +{
>> +     struct xgene_dma_desc_sw *first = NULL, *new;
>> +     struct xgene_dma_chan *chan;
>> +     size_t copy;
>> +     u32 desc_id;
>> +
>> +     if (unlikely(!dchan || !len))
>> +             return NULL;
>> +
>> +     chan = to_dma_chan(dchan);
>> +
>> +     /* Get the id for this group of descriptors */
>> +     desc_id = atomic_inc_return(&chan->desc_id);
>> +
>> +     do {
>> +             /* Allocate the link descriptor from DMA pool */
>> +             new = xgene_dma_alloc_descriptor(chan);
>> +             if (!new)
>> +                     goto fail;
>> +
>> +             /* Create the largest transaction possible */
>> +             copy = min_t(size_t, len, DMA_MAX_64B_DESC_BYTE_CNT);
>> +
>> +             /* Prepare DMA descriptor */
>> +             xgene_dma_prep_cpy_desc(chan, new, dst, src, copy, desc_id);
>> +
>> +             if (!first)
>> +                     first = new;
>> +
>> +             new->first = first;
>> +             first->desc_cnt++;
>> +             new->desc_id = desc_id;
>> +
>> +             new->tx.cookie = 0;
>> +             async_tx_ack(&new->tx);
>> +
>> +             /* Update metadata */
>> +             len -= copy;
>> +             dst += copy;
>> +             src += copy;
>> +
>> +             /* Insert the link descriptor to the LD ring */
>> +             list_add_tail(&new->node, &first->tx_list);
>> +     } while (len);
>> +
>> +     first->tx.flags = flags; /* client is in control of this ack */
>> +     first->tx.cookie = -EBUSY;
>> +     first->flags |= DMA_FLAG_FIRST_DESC;
>> +
>> +     return &first->tx;
> where are you mapping dma buffers?
>
>> +static enum dma_status xgene_dma_find_tx_desc_status(
>> +     struct xgene_dma_chan *chan, dma_cookie_t cookie,
>> +     struct dma_tx_state *txstate)
>> +{
>> +     struct xgene_dma_desc_sw *desc;
>> +
>> +     spin_lock_bh(&chan->lock);
>> +
>> +     /* Check if this tx descriptor is still in pending queue */
>> +     list_for_each_entry(desc, &chan->ld_pending, node) {
>> +             if (desc->tx.cookie == cookie) {
>> +                     xgene_chan_xfer_ld_pending(chan);
> why are you calling this here, status check shouldnt do this...
>> +                     spin_unlock_bh(&chan->lock);
>> +                     return DMA_IN_PROGRESS;
> residue here is size of transacation.
>> +             }
>> +     }
>> +
>> +     /* Check if this descriptor is in running queue */
>> +     list_for_each_entry(desc, &chan->ld_running, node) {
>> +             if (desc->tx.cookie == cookie) {
>> +                     /* Cleanup any running and executed descriptors */
>> +                     xgene_dma_cleanup_descriptors(chan);
> ditto?
>> +                     spin_unlock_bh(&chan->lock);
>> +                     return dma_cookie_status(&chan->dma_chan,
>> +                                              cookie, txstate);
> and you havent touched txstate so what is the intent here...?
>> +             }
>> +     }
>> +
>> +     spin_unlock_bh(&chan->lock);
>> +
>> +     return DMA_COMPLETE;
>> +}
>> +
>> +static enum dma_status xgene_dma_tx_status(struct dma_chan *dchan,
>> +                                        dma_cookie_t cookie,
>> +                                        struct dma_tx_state *txstate)
>> +{
>> +     struct xgene_dma_chan *chan = to_dma_chan(dchan);
>> +
>> +     enum dma_status status;
>> +
>> +     status = dma_cookie_status(dchan, cookie, txstate);
>> +     if (status == DMA_COMPLETE)
> you should do this if txstate in NULL, no point doing calculations..

I didn't get you here. Can you explain me.

>
>> +             return status;
>> +
>> +     return xgene_dma_find_tx_desc_status(chan, cookie, txstate);
>> +}
>> +
>> +static void xgene_dma_tasklet_cb(unsigned long data)
>> +{
>> +     struct xgene_dma_chan *chan = (struct xgene_dma_chan *)data;
>> +
>> +     spin_lock_bh(&chan->lock);
>> +
>> +     /* Run all cleanup for descriptors which have been completed */
>> +     xgene_dma_cleanup_descriptors(chan);
>> +
>> +     /* Re-enable DMA channel IRQ */
>> +     enable_irq(chan->rx_irq);
>> +
>> +     spin_unlock_bh(&chan->lock);
>> +}
>> +
>> +static irqreturn_t xgene_dma_chan_ring_isr(int irq, void *id)
>> +{
>> +     struct xgene_dma_chan *chan = (struct xgene_dma_chan *)id;
>> +
>> +     BUG_ON(!chan);
>> +
>> +     /*
>> +      * Disable DMA channel IRQ until we process completed
>> +      * descriptors
>> +      */
>> +     disable_irq_nosync(chan->rx_irq);
> and why is that?
>
>> +
>> +     /*
>> +      * Schedule the tasklet to handle all cleanup of the current
>> +      * transaction. It will start a new transaction if there is
>> +      * one pending.
>> +      */
>> +     tasklet_schedule(&chan->tasklet);
> for better results why not schedule the next transaction here..?
>> +
>> +     return IRQ_HANDLED;
>> +}
>> +
>
>> +static void xgene_dma_async_unregister(struct xgene_dma *pdma)
>> +{
>> +     int i;
>> +
>> +     for (i = 0; i < DMA_MAX_CHANNEL; i++)
>> +             dma_async_device_unregister(&pdma->dma_dev[i]);
> how do you ensure irq is disabled and tasklets killed?
>
>> +MODULE_DESCRIPTION("APM X-Gene SoC DMA driver");
>> +MODULE_AUTHOR("Rameshwar Prasad Sahu <rsahu@xxxxxxx>");
>> +MODULE_AUTHOR("Loc Ho <lho@xxxxxxx>");
>> +MODULE_LICENSE("GPL");
>> +MODULE_VERSION("1.0");
> why do you need this?
>> --
>> 1.8.2.1
>>
>
> --
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