[PATCH v5 1/3] dmaengine: Add support for APM X-Gene SoC DMA engine driver
Vinod Koul
vinod.koul at intel.com
Wed Feb 4 17:50:31 PST 2015
On Tue, Feb 03, 2015 at 06:25:05PM +0530, Rameshwar Prasad Sahu wrote:
> +/* Applied Micro X-Gene SoC DMA engine Driver
> + *
> + * Copyright (c) 2014, Applied Micro Circuits Corporation
not 2015?
> + * Authors: Rameshwar Prasad Sahu <rsahu at apm.com>
> + * Loc Ho <lho at apm.com>
> + *
> +/* DMA ring csr registers and bit definations */
> +#define RING_CONFIG 0x04
> +#define RING_ENABLE BIT(31)
> +#define RING_ID 0x08
> +#define RING_ID_SETUP(v) ((v) | BIT(31))
> +#define RING_ID_BUF 0x0C
> +#define RING_ID_BUF_SETUP(v) (((v) << 9) | BIT(21))
> +#define RING_THRESLD0_SET1 0x30
> +#define RING_THRESLD0_SET1_VAL 0X64
> +#define RING_THRESLD1_SET1 0x34
> +#define RING_THRESLD1_SET1_VAL 0xC8
> +#define RING_HYSTERESIS 0x68
> +#define RING_HYSTERESIS_VAL 0xFFFFFFFF
> +#define RING_STATE 0x6C
> +#define RING_STATE_WR_BASE 0x70
> +#define RING_NE_INT_MODE 0x017C
> +#define RING_NE_INT_MODE_SET(m, v) \
> + ((m) = ((m) & ~BIT(31 - (v))) | BIT(31 - (v)))
> +#define RING_NE_INT_MODE_RESET(m, v) \
> + ((m) &= (~BIT(31 - (v))))
> +#define RING_CLKEN 0xC208
> +#define RING_SRST 0xC200
> +#define RING_MEM_RAM_SHUTDOWN 0xD070
> +#define RING_BLK_MEM_RDY 0xD074
> +#define RING_BLK_MEM_RDY_VAL 0xFFFFFFFF
> +#define RING_ID_GET(owner, num) (((owner) << 6) | (num))
> +#define RING_DST_RING_ID(v) ((1 << 10) | (v))
> +#define RING_CMD_OFFSET(v) (((v) << 6) + 0x2C)
> +#define RING_COHERENT_SET(m) (((u32 *)(m))[2] |= BIT(4))
> +#define RING_ADDRL_SET(m, v) (((u32 *)(m))[2] |= (((v) >> 8) << 5))
> +#define RING_ADDRH_SET(m, v) (((u32 *)(m))[3] |= ((v) >> 35))
> +#define RING_ACCEPTLERR_SET(m) (((u32 *)(m))[3] |= BIT(19))
> +#define RING_SIZE_SET(m, v) (((u32 *)(m))[3] |= ((v) << 23))
> +#define RING_RECOMBBUF_SET(m) (((u32 *)(m))[3] |= BIT(27))
> +#define RING_RECOMTIMEOUTL_SET(m) \
> + (((u32 *)(m))[3] |= (0x7 << 28))
> +#define RING_RECOMTIMEOUTH_SET(m) \
> + (((u32 *)(m))[4] |= 0x3)
> +#define RING_SELTHRSH_SET(m) (((u32 *)(m))[4] |= BIT(3))
> +#define RING_TYPE_SET(m, v) (((u32 *)(m))[4] |= ((v) << 19))a
these defines and the ones which follow need to be namespace aptly
> +static void xgene_dma_cpu_to_le64(u64 *desc, int count)
why is this endian specific?
> +
> +static irqreturn_t xgene_dma_ring_isr(int irq, void *id)
> +{
> + struct xgene_dma_chan *chan = (struct xgene_dma_chan *)id;
> +
> + BUG_ON(!chan);
> +
> + /* Disable DMA channel IRQ */
> + disable_irq_nosync(chan->rx_irq);
> +
> + /* Schedule tasklet */
> + tasklet_schedule(&chan->rx_tasklet);
> +
Ideally you should submit next txn here, but...
> +
> +static int xgene_dma_alloc_chan_resources(struct dma_chan *channel)
> +{
> + struct xgene_dma_chan *chan = to_xgene_dma_chan(channel);
> + int i;
> +
> + /* Check if we have already allcated resources */
> + if (chan->slots)
> + return DMA_SLOT_PER_CHANNEL;
> +
> + spin_lock_bh(&chan->lock);
> +
> + chan->slots = devm_kzalloc(chan->pdma->dev,
> + sizeof(struct xgene_dma_slot) *
> + DMA_SLOT_PER_CHANNEL, GFP_ATOMIC);
GFP_NOWAIT pls
> +
> +static enum dma_status xgene_dma_tx_status(struct dma_chan *channel,
> + dma_cookie_t cookie,
> + struct dma_tx_state *txstate)
> +{
> + return dma_cookie_status(channel, cookie, txstate);
why no residue calculation
> +}
> +
> +static void xgene_dma_issue_pending(struct dma_chan *channel)
> +{
> + /* Nothing to do */
> +}
What do you mean by nothing to do here
See Documentation/dmaengine/client.txt Section 4 & 5
> +static dma_cookie_t xgene_dma_tx_memcpy_submit(
> + struct dma_async_tx_descriptor *tx)
> +{
> + struct xgene_dma_chan *chan = to_xgene_dma_chan(tx->chan);
> + struct xgene_dma_slot *slot = to_xgene_dma_slot(tx);
> + dma_addr_t dst = slot->dst;
> + dma_addr_t src = slot->src;
> + size_t len = slot->len;
> + size_t copy;
> + dma_cookie_t cookie;
> +
> + spin_lock_bh(&chan->lock);
> +
> + chan->tx_cmd = 0;
> + slot->desc_cnt = 0;
> +
> + /* Run until we are out of length */
> + do {
> + /* Create the largest transaction possible */
> + copy = min_t(size_t, len, DMA_MAX_64BDSC_BYTE_CNT);
> +
> + /* Prepare DMA descriptor */
> + xgene_dma_prep_cpy_desc(chan, slot, dst, src, copy);
> +
This is wrong. The descriptor is supposed to be already prepared and now it
has to be submitted to queue
> +static struct dma_async_tx_descriptor *xgene_dma_prep_memcpy(
> + struct dma_chan *channel, dma_addr_t dst, dma_addr_t src,
> + size_t len, unsigned long flags)
> +{
> + struct xgene_dma_chan *chan = to_xgene_dma_chan(channel);
> + struct xgene_dma_slot *slot;
> +
> + /* Sanity check */
> + BUG_ON(len > DMA_MAX_MEMCPY_BYTE_CNT);
> +
> + spin_lock_bh(&chan->lock);
> +
> + slot = xgene_dma_get_channel_slot(chan);
> + if (!slot) {
> + spin_unlock_bh(&chan->lock);
> + return NULL;
> + }
> +
> + dev_dbg(chan->pdma->dev,
> + "MEMCPY channel %d slot %d len 0x%zX dst 0x%llX src 0x%llX\n",
> + chan->index, slot->index, len, dst, src);
> +
> + /* Setup slot variables */
> + slot->flags = FLAG_SLOT_IN_USE;
> + slot->txd.flags = flags;
> + slot->txd.tx_submit = xgene_dma_tx_memcpy_submit;
> +
> + /*
> + * Due to the race in tx_submit call from the client,
> + * need to serialize the submission of H/W DMA descriptors.
> + * So make shadow copy to prepare DMA descriptor during
> + * tx_submit call.
> + */
> + slot->dst = dst;
> + slot->src = src;
> + slot->len = len;
> +
> + spin_unlock_bh(&chan->lock);
> +
> + return &slot->txd;
Nope, you are supposed to allocate and populate a descriptor here
> +}
> +
> +static dma_cookie_t xgene_dma_tx_sgcpy_submit(
> + struct dma_async_tx_descriptor *tx)
> +{
> + struct xgene_dma_chan *chan = to_xgene_dma_chan(tx->chan);
> + struct xgene_dma_slot *slot = to_xgene_dma_slot(tx);
> + struct scatterlist *dst_sg, *src_sg;
> + size_t dst_avail, src_avail;
> + dma_addr_t dst, src;
> + size_t len;
> + dma_cookie_t cookie;
> + size_t nbytes = slot->len;
> +
> + spin_lock_bh(&chan->lock);
> +
> + dst_sg = slot->srcdst_list + slot->src_nents;
> + src_sg = slot->srcdst_list;
> +
> + chan->tx_cmd = 0;
> + slot->desc_cnt = 0;
> +
> + /* Get prepared for the loop */
> + dst_avail = sg_dma_len(dst_sg);
> + src_avail = sg_dma_len(src_sg);
> +
> + /* Run until we are out of length */
> + do {
> + /* Create the largest transaction possible */
> + len = min_t(size_t, src_avail, dst_avail);
> + len = min_t(size_t, len, DMA_MAX_64BDSC_BYTE_CNT);
> + if (len == 0)
> + goto fetch;
> +
> + dst = sg_dma_address(dst_sg) + sg_dma_len(dst_sg) - dst_avail;
> + src = sg_dma_address(src_sg) + sg_dma_len(src_sg) - src_avail;
> +
> + /* Prepare DMA descriptor */
> + xgene_dma_prep_cpy_desc(chan, slot, dst, src, len);
again this wrong, also you should ideally have single submit. Why does it
have to be transfer type dependent.
> +
> +static void xgene_dma_set_caps(struct xgene_dma_chan *chan,
> + struct dma_device *dma_dev)
> +{
> + /* Initialize DMA device capability mask */
> + dma_cap_zero(dma_dev->cap_mask);
> +
> + /* Set DMA device capability */
> + dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask);
> + dma_cap_set(DMA_SG, dma_dev->cap_mask);
> +
> + /* Set base and prep routines */
> + dma_dev->dev = chan->pdma->dev;
> + dma_dev->device_alloc_chan_resources = xgene_dma_alloc_chan_resources;
> + dma_dev->device_free_chan_resources = xgene_dma_free_chan_resources;
> + dma_dev->device_issue_pending = xgene_dma_issue_pending;
> + dma_dev->device_tx_status = xgene_dma_tx_status;
> +
> + if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask))
> + dma_dev->device_prep_dma_memcpy = xgene_dma_prep_memcpy;
> +
> + if (dma_has_cap(DMA_SG, dma_dev->cap_mask))
> + dma_dev->device_prep_dma_sg = xgene_dma_prep_sg;
these two if conditions dont make any sense
> +static int xgene_dma_runtime_resume(struct device *dev)
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> + struct xgene_dma *pdma = platform_get_drvdata(pdev);
> + int ret;
> +
> + ret = clk_prepare_enable(pdma->dma_clk);
> + if (ret) {
> + dev_err(dev, "Failed to enable clk %d\n", ret);
> + return ret;
> + }
> +
> + return 0;
> +}
This should be under runtime pm flag. people can run kernels with these
disabled
> +
> +static int xgene_dma_remove(struct platform_device *pdev)
> +{
> + struct xgene_dma *pdma = platform_get_drvdata(pdev);
> + struct xgene_dma_chan *chan;
> + int i;
> +
> + for (i = 0; i < DMA_MAX_CHANNEL; i++) {
> + chan = &pdma->channels[i];
> +
> + /* Delete DMA ring descriptors */
> + xgene_dma_delete_chan_rings(chan);
> +
> + /* Kill the DMA channel tasklet */
> + tasklet_kill(&chan->rx_tasklet);
> +
But your irq is still active and can be triggered!
> + /* Unregister DMA device */
> + dma_async_device_unregister(&pdma->dma_dev[i]);
> + }
> +
> + pm_runtime_disable(&pdev->dev);
> + if (!pm_runtime_status_suspended(&pdev->dev))
> + xgene_dma_runtime_suspend(&pdev->dev);
> +
> + return 0;
> +}
Okay we need some good work here. First cleanup the usage of dmaengine APIs.
Second I would like to see cookie management and descriptor management
cleaned by using helpers available
--
~Vinod
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