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Date: Fri, 5 Dec 2014 10:30:53 -0800
From: Andrew Bresticker <abrestic@...omium.org>
To: Vinod Koul <vinod.koul@...el.com>
Cc: Dan Williams <dan.j.williams@...el.com>,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
Grant Likely <grant.likely@...aro.org>,
James Hartley <james.hartley@...tec.com>,
James Hogan <james.hogan@...tec.com>,
Ezequiel Garcia <ezequiel.garcia@...tec.com>,
Damien Horsley <Damien.Horsley@...tec.com>,
Arnd Bergmann <arnd@...db.de>, dmaengine@...r.kernel.org,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2 2/2] dmaengine: Add driver for IMG MDC
Thanks for the review Vinod!
On Fri, Dec 5, 2014 at 9:35 AM, Vinod Koul <vinod.koul@...el.com> wrote:
> On Fri, Nov 14, 2014 at 01:59:43PM -0800, Andrew Bresticker wrote:
>> +static inline unsigned int to_mdc_width(enum dma_slave_buswidth bw)
>> +{
>> + switch (bw) {
>> + case DMA_SLAVE_BUSWIDTH_1_BYTE:
>> + return 0;
>> + case DMA_SLAVE_BUSWIDTH_2_BYTES:
>> + return 1;
>> + case DMA_SLAVE_BUSWIDTH_4_BYTES:
>> + return 2;
>> + case DMA_SLAVE_BUSWIDTH_8_BYTES:
>> + return 3;
> ffs()?
Ok.
>> + default:
>> + return 2;
> for slave cases default makes little sense, better to return error?
Sure.
>> + }
>> +}
>> +
>> +static void mdc_list_desc_config(struct mdc_chan *mchan,
>> + struct mdc_hw_list_desc *ldesc,
>> + enum dma_transfer_direction dir,
>> + dma_addr_t src, dma_addr_t dst, size_t len)
>> +{
>> + struct mdc_dma *mdma = mchan->mdma;
>> + unsigned int max_burst, burst_size;
>> +
>> + ldesc->gen_conf = MDC_GENERAL_CONFIG_IEN | MDC_GENERAL_CONFIG_LIST_IEN |
>> + MDC_GENERAL_CONFIG_LEVEL_INT | MDC_GENERAL_CONFIG_PHYSICAL_W |
>> + MDC_GENERAL_CONFIG_PHYSICAL_R;
>> + ldesc->readport_conf =
>> + (mchan->thread << MDC_READ_PORT_CONFIG_STHREAD_SHIFT) |
>> + (mchan->thread << MDC_READ_PORT_CONFIG_RTHREAD_SHIFT) |
>> + (mchan->thread << MDC_READ_PORT_CONFIG_WTHREAD_SHIFT);
>> + ldesc->read_addr = src;
>> + ldesc->write_addr = dst;
>> + ldesc->xfer_size = len - 1;
>> + ldesc->node_addr = 0;
>> + ldesc->cmds_done = 0;
>> + ldesc->ctrl_status = MDC_CONTROL_AND_STATUS_LIST_EN |
>> + MDC_CONTROL_AND_STATUS_EN;
>> + ldesc->next_desc = NULL;
>> +
>> + if ((dst % mdma->bus_width == 0) && (src % mdma->bus_width == 0))
>> + max_burst = mdma->bus_width * mdma->max_burst_mult;
>> + else
>> + max_burst = mdma->bus_width * (mdma->max_burst_mult - 1);
> sounds like you should use something like ALIGN ?
Yup.
>> +
>> + if (dir == DMA_MEM_TO_DEV) {
>> + ldesc->gen_conf |= MDC_GENERAL_CONFIG_INC_R |
>> + ((fls(mdma->bus_width) - 1) <<
> bus_width calculation is repeated quite few times, would help readability if
> we hanlde this in macro.
Yes, will do.
> Also this be using src/dstn_addr_widths based on direction passed.
The above is setting the memory (not slave) bus width which is fixed
and not a per-slave property.
>> + MDC_GENERAL_CONFIG_WIDTH_R_SHIFT) |
>> + (to_mdc_width(mchan->config.dst_addr_width) <<
>> + MDC_GENERAL_CONFIG_WIDTH_W_SHIFT);
> and a macro for this calculation, which take args for different cases would
> help a lot!
Ok.
>> + ldesc->readport_conf |= MDC_READ_PORT_CONFIG_DREQ_ENABLE;
>> + burst_size = min(max_burst, mchan->config.dst_maxburst *
>> + mchan->config.dst_addr_width);
>> + } else if (dir == DMA_DEV_TO_MEM) {
>> + ldesc->gen_conf |= MDC_GENERAL_CONFIG_INC_W |
>> + (to_mdc_width(mchan->config.src_addr_width) <<
>> + MDC_GENERAL_CONFIG_WIDTH_R_SHIFT) |
>> + ((fls(mdma->bus_width) - 1) <<
>> + MDC_GENERAL_CONFIG_WIDTH_W_SHIFT);
>> + ldesc->readport_conf |= MDC_READ_PORT_CONFIG_DREQ_ENABLE;
>> + burst_size = min(max_burst, mchan->config.src_maxburst *
>> + mchan->config.src_addr_width);
>> + } else {
> DEV_TO_DEV too?
No, but it's not possible to have dir == DEV_TO_DEV here. The callers
(mdc_prep_xxx) will check the direcioin.
>> + ldesc->gen_conf |= MDC_GENERAL_CONFIG_INC_R |
>> + MDC_GENERAL_CONFIG_INC_W |
>> + ((fls(mdma->bus_width) - 1) <<
>> + MDC_GENERAL_CONFIG_WIDTH_R_SHIFT) |
>> + ((fls(mdma->bus_width) - 1) <<
>> + MDC_GENERAL_CONFIG_WIDTH_W_SHIFT);
>> + burst_size = max_burst;
> btw this piece is very hard to read, please do improve upon
After adding a macro for setting the WIDTH_{R,W} fields it seems fine
to me. Is there something else you had in mind?
>> +static struct dma_async_tx_descriptor *mdc_prep_dma_memcpy(
>> + struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, size_t len,
>> + unsigned long flags)
>> +{
>> + struct mdc_chan *mchan = to_mdc_chan(chan);
>> + struct mdc_dma *mdma = mchan->mdma;
>> + struct mdc_tx_desc *mdesc;
>> + struct mdc_hw_list_desc *curr, *prev = NULL;
>> + dma_addr_t curr_phys, prev_phys;
>> +
>> + if (!len)
>> + return NULL;
>> +
>> + mdesc = kzalloc(sizeof(*mdesc), GFP_NOWAIT);
>> + if (!mdesc)
>> + return NULL;
>> + mdesc->chan = mchan;
>> + mdesc->list_xfer_size = len;
>> +
>> + while (len > 0) {
>> + size_t xfer_size;
>> +
>> + curr = dma_pool_alloc(mdma->desc_pool, GFP_NOWAIT, &curr_phys);
>> + if (!curr)
>> + goto free_desc;
>> +
>> + if (prev) {
>> + prev->node_addr = curr_phys;
>> + prev->next_desc = curr;
>> + } else {
>> + mdesc->list_phys = curr_phys;
>> + mdesc->list = curr;
>> + }
>> +
>> + xfer_size = min_t(size_t, mdma->max_xfer_size, len);
>> +
>> + mdc_list_desc_config(mchan, curr, DMA_MEM_TO_MEM, src, dest,
>> + xfer_size);
> and this depends on dma_slave_config being set, which shouldn't be the case
> for memcpy
It doesn't. mdc_list_desc_config only looks at mchan->config in the
slave cases.
>> +static enum dma_status mdc_tx_status(struct dma_chan *chan,
>> + dma_cookie_t cookie, struct dma_tx_state *txstate)
>> +{
>> + struct mdc_chan *mchan = to_mdc_chan(chan);
>> + struct mdc_tx_desc *mdesc;
>> + struct virt_dma_desc *vd;
>> + unsigned long flags;
>> + size_t bytes = 0;
>> + int ret;
>> +
>> + ret = dma_cookie_status(chan, cookie, txstate);
>> + if (ret == DMA_COMPLETE)
>> + return ret;
>> +
> you should check txstate before proceeding. It can be null too
Ok.
>> +
>> +static int mdc_slave_config(struct dma_chan *chan,
>> + struct dma_slave_config *config)
>> +{
>> + struct mdc_chan *mchan = to_mdc_chan(chan);
>> + unsigned long flags;
>> +
>> + spin_lock_irqsave(&mchan->vc.lock, flags);
>> + if (config->direction == DMA_MEM_TO_DEV) {
>> + config->dst_addr_width = min(config->dst_addr_width,
>> + mchan->mdma->bus_width);
>> + } else {
>> + config->src_addr_width = min(config->src_addr_width,
>> + mchan->mdma->bus_width);
> direction field is deprecated pls don't use that. Use the prep_xx direction
> argument instead
Ok.
>> +static int mdc_dma_remove(struct platform_device *pdev)
>> +{
>> + struct mdc_dma *mdma = platform_get_drvdata(pdev);
>> +
>> + of_dma_controller_free(pdev->dev.of_node);
>> + dma_async_device_unregister(&mdma->dma_dev);
>> + clk_disable_unprepare(mdma->clk);
> you need to call devm_irq_free() explicitly and also ensure you kill your
> tasklet and syncronize irq()
Ok.
> Plus a rebase on Maxime's series which will be merged in required
This patch is already based on Maxime's series.
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