Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Mon, 23 Dec 2019 13:04:25 +0530
From:   Vinod Koul <vkoul@kernel.org>
To:     Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc:     robh+dt@kernel.org, nm@ti.com, ssantosh@kernel.org,
        dan.j.williams@intel.com, dmaengine@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, grygorii.strashko@ti.com,
        lokeshvutla@ti.com, t-kristo@ti.com, tony@atomide.com,
        j-keerthy@ti.com, vigneshr@ti.com
Subject: Re: [PATCH v7 09/12] dmaengine: ti: New driver for K3 UDMA
Message-ID: <20191223073425.GV2536@vkoul-mobl>
References: <20191209094332.4047-1-peter.ujfalusi@ti.com>
 <20191209094332.4047-10-peter.ujfalusi@ti.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20191209094332.4047-10-peter.ujfalusi@ti.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 09-12-19, 11:43, Peter Ujfalusi wrote:

> +#include <linux/kernel.h>
> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/dmapool.h>
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +#include <linux/of.h>
> +#include <linux/of_dma.h>
> +#include <linux/of_device.h>
> +#include <linux/of_irq.h>

to many of headers, do we need all!

> +static char *udma_get_dir_text(enum dma_transfer_direction dir)
> +{
> +	switch (dir) {
> +	case DMA_DEV_TO_MEM:
> +		return "DEV_TO_MEM";
> +	case DMA_MEM_TO_DEV:
> +		return "MEM_TO_DEV";
> +	case DMA_MEM_TO_MEM:
> +		return "MEM_TO_MEM";
> +	case DMA_DEV_TO_DEV:
> +		return "DEV_TO_DEV";
> +	default:
> +		break;
> +	}
> +
> +	return "invalid";
> +}

this seems generic which other ppl may need, can we move it to core.

> +
> +static void udma_reset_uchan(struct udma_chan *uc)
> +{
> +	uc->state = UDMA_CHAN_IS_IDLE;
> +	uc->remote_thread_id = -1;
> +	uc->dir = DMA_MEM_TO_MEM;
> +	uc->pkt_mode = false;
> +	uc->ep_type = PSIL_EP_NATIVE;
> +	uc->enable_acc32 = 0;
> +	uc->enable_burst = 0;
> +	uc->channel_tpl = 0;
> +	uc->psd_size = 0;
> +	uc->metadata_size = 0;
> +	uc->hdesc_size = 0;
> +	uc->notdpkt = 0;

rather than do setting zero, why note memset and then set the nonzero
members only?

> +static void udma_reset_counters(struct udma_chan *uc)
> +{
> +	u32 val;
> +
> +	if (uc->tchan) {
> +		val = udma_tchanrt_read(uc->tchan, UDMA_TCHAN_RT_BCNT_REG);
> +		udma_tchanrt_write(uc->tchan, UDMA_TCHAN_RT_BCNT_REG, val);

so you read back from UDMA_TCHAN_RT_BCNT_REG and write same value to
it??

> +
> +		val = udma_tchanrt_read(uc->tchan, UDMA_TCHAN_RT_SBCNT_REG);
> +		udma_tchanrt_write(uc->tchan, UDMA_TCHAN_RT_SBCNT_REG, val);
> +
> +		val = udma_tchanrt_read(uc->tchan, UDMA_TCHAN_RT_PCNT_REG);
> +		udma_tchanrt_write(uc->tchan, UDMA_TCHAN_RT_PCNT_REG, val);
> +
> +		val = udma_tchanrt_read(uc->tchan, UDMA_TCHAN_RT_PEER_BCNT_REG);
> +		udma_tchanrt_write(uc->tchan, UDMA_TCHAN_RT_PEER_BCNT_REG, val);
> +	}
> +
> +	if (uc->rchan) {
> +		val = udma_rchanrt_read(uc->rchan, UDMA_RCHAN_RT_BCNT_REG);
> +		udma_rchanrt_write(uc->rchan, UDMA_RCHAN_RT_BCNT_REG, val);
> +
> +		val = udma_rchanrt_read(uc->rchan, UDMA_RCHAN_RT_SBCNT_REG);
> +		udma_rchanrt_write(uc->rchan, UDMA_RCHAN_RT_SBCNT_REG, val);
> +
> +		val = udma_rchanrt_read(uc->rchan, UDMA_RCHAN_RT_PCNT_REG);
> +		udma_rchanrt_write(uc->rchan, UDMA_RCHAN_RT_PCNT_REG, val);
> +
> +		val = udma_rchanrt_read(uc->rchan, UDMA_RCHAN_RT_PEER_BCNT_REG);
> +		udma_rchanrt_write(uc->rchan, UDMA_RCHAN_RT_PEER_BCNT_REG, val);

True for all of these, what am I missing :)

> +static int udma_start(struct udma_chan *uc)
> +{
> +	struct virt_dma_desc *vd = vchan_next_desc(&uc->vc);
> +
> +	if (!vd) {
> +		uc->desc = NULL;
> +		return -ENOENT;
> +	}
> +
> +	list_del(&vd->node);
> +
> +	uc->desc = to_udma_desc(&vd->tx);
> +
> +	/* Channel is already running and does not need reconfiguration */
> +	if (udma_is_chan_running(uc) && !udma_chan_needs_reconfiguration(uc)) {
> +		udma_start_desc(uc);
> +		goto out;

How about the case where settings are different than the current one?

> +static struct udma_desc *udma_alloc_tr_desc(struct udma_chan *uc,
> +					    size_t tr_size, int tr_count,
> +					    enum dma_transfer_direction dir)
> +{
> +	struct udma_hwdesc *hwdesc;
> +	struct cppi5_desc_hdr_t *tr_desc;
> +	struct udma_desc *d;
> +	u32 reload_count = 0;
> +	u32 ring_id;
> +
> +	switch (tr_size) {
> +	case 16:
> +	case 32:
> +	case 64:
> +	case 128:
> +		break;
> +	default:
> +		dev_err(uc->ud->dev, "Unsupported TR size of %zu\n", tr_size);
> +		return NULL;
> +	}
> +
> +	/* We have only one descriptor containing multiple TRs */
> +	d = kzalloc(sizeof(*d) + sizeof(d->hwdesc[0]), GFP_ATOMIC);

this is invoked from prep_ so should use GFP_NOWAIT, we dont use
GFP_ATOMIC :)

> +static struct udma_desc *
> +udma_prep_slave_sg_tr(struct udma_chan *uc, struct scatterlist *sgl,
> +		      unsigned int sglen, enum dma_transfer_direction dir,
> +		      unsigned long tx_flags, void *context)
> +{
> +	enum dma_slave_buswidth dev_width;
> +	struct scatterlist *sgent;
> +	struct udma_desc *d;
> +	size_t tr_size;
> +	struct cppi5_tr_type1_t *tr_req = NULL;
> +	unsigned int i;
> +	u32 burst;
> +
> +	if (dir == DMA_DEV_TO_MEM) {
> +		dev_width = uc->cfg.src_addr_width;
> +		burst = uc->cfg.src_maxburst;
> +	} else if (dir == DMA_MEM_TO_DEV) {
> +		dev_width = uc->cfg.dst_addr_width;
> +		burst = uc->cfg.dst_maxburst;
> +	} else {
> +		dev_err(uc->ud->dev, "%s: bad direction?\n", __func__);
> +		return NULL;
> +	}
> +
> +	if (!burst)
> +		burst = 1;
> +
> +	/* Now allocate and setup the descriptor. */
> +	tr_size = sizeof(struct cppi5_tr_type1_t);
> +	d = udma_alloc_tr_desc(uc, tr_size, sglen, dir);
> +	if (!d)
> +		return NULL;
> +
> +	d->sglen = sglen;
> +
> +	tr_req = (struct cppi5_tr_type1_t *)d->hwdesc[0].tr_req_base;

cast away from void *?

> +static int udma_configure_statictr(struct udma_chan *uc, struct udma_desc *d,
> +				   enum dma_slave_buswidth dev_width,
> +				   u16 elcnt)
> +{
> +	if (uc->ep_type != PSIL_EP_PDMA_XY)
> +		return 0;
> +
> +	/* Bus width translates to the element size (ES) */
> +	switch (dev_width) {
> +	case DMA_SLAVE_BUSWIDTH_1_BYTE:
> +		d->static_tr.elsize = 0;
> +		break;
> +	case DMA_SLAVE_BUSWIDTH_2_BYTES:
> +		d->static_tr.elsize = 1;
> +		break;
> +	case DMA_SLAVE_BUSWIDTH_3_BYTES:
> +		d->static_tr.elsize = 2;
> +		break;
> +	case DMA_SLAVE_BUSWIDTH_4_BYTES:
> +		d->static_tr.elsize = 3;
> +		break;
> +	case DMA_SLAVE_BUSWIDTH_8_BYTES:
> +		d->static_tr.elsize = 4;

seems like ffs(dev_width) to me?

> +static struct udma_desc *
> +udma_prep_slave_sg_pkt(struct udma_chan *uc, struct scatterlist *sgl,
> +		       unsigned int sglen, enum dma_transfer_direction dir,
> +		       unsigned long tx_flags, void *context)
> +{
> +	struct scatterlist *sgent;
> +	struct cppi5_host_desc_t *h_desc = NULL;
> +	struct udma_desc *d;
> +	u32 ring_id;
> +	unsigned int i;
> +
> +	d = kzalloc(sizeof(*d) + sglen * sizeof(d->hwdesc[0]), GFP_ATOMIC);

GFP_NOWAIT here and few other places

> +static struct udma_desc *
> +udma_prep_dma_cyclic_pkt(struct udma_chan *uc, dma_addr_t buf_addr,
> +			 size_t buf_len, size_t period_len,
> +			 enum dma_transfer_direction dir, unsigned long flags)
> +{
> +	struct udma_desc *d;
> +	u32 ring_id;
> +	int i;
> +	int periods = buf_len / period_len;
> +
> +	if (periods > (K3_UDMA_DEFAULT_RING_SIZE - 1))
> +		return NULL;
> +
> +	if (period_len > 0x3FFFFF)

Magic?

> +static enum dma_status udma_tx_status(struct dma_chan *chan,
> +				      dma_cookie_t cookie,
> +				      struct dma_tx_state *txstate)
> +{
> +	struct udma_chan *uc = to_udma_chan(chan);
> +	enum dma_status ret;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&uc->vc.lock, flags);
> +
> +	ret = dma_cookie_status(chan, cookie, txstate);
> +
> +	if (!udma_is_chan_running(uc))
> +		ret = DMA_COMPLETE;

Even for paused, not started channel? Not sure what will be return on those cases
-- 
~Vinod