Re: [PATCH v2 1/2] dmaengine: Introduce DW AXI DMAC driver

From: Vinod Koul
Date: Fri Mar 02 2018 - 03:09:45 EST


On Mon, Feb 26, 2018 at 05:56:27PM +0300, Eugeniy Paltsev wrote:

> +/*
> + * Synopsys DesignWare AXI DMA Controller driver.
> + *
> + * Copyright (C) 2017-2018 Synopsys, Inc. (www.synopsys.com)
> + * Author: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
> + *
> + * SPDX-License-Identifier: GPL-2.0
> + */

This needs to be in below style

// SPDX-License-Identifier: GPL-2.0
// Copyright (C) ....

/*
* other things u want to add
*/

> +#define DRV_NAME "axi_dw_dmac"

how about use KBUILD_MODNAME here?

> +static enum dma_status
> +dma_chan_tx_status(struct dma_chan *dchan, dma_cookie_t cookie,
> + struct dma_tx_state *txstate)
> +{
> + struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);
> + enum dma_status ret;
> +
> + ret = dma_cookie_status(dchan, cookie, txstate);
> +
> + if (chan->is_paused && ret == DMA_IN_PROGRESS)
> + return DMA_PAUSED;
> +
> + return ret;

nitpick, how about

if (chan->is_paused && ret == DMA_IN_PROGRESS)
ret = DMA_PAUSED;

return ret;

that way we have single point of return.

> +static int dma_chan_alloc_chan_resources(struct dma_chan *dchan)
> +{
> + struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);
> +
> + /* ASSERT: channel is idle */
> + if (axi_chan_is_hw_enable(chan)) {
> + dev_err(chan2dev(chan), "%s is non-idle!\n",
> + axi_chan_name(chan));
> + return -EBUSY;
> + }
> +
> + dev_vdbg(dchan2dev(dchan), "%s: allocating\n", axi_chan_name(chan));
> +
> + dma_cookie_init(dchan);

This is already done as part of vchan_init(), so why is it called explicitly
and why is that not invoked here?

> +static void dma_chan_free_chan_resources(struct dma_chan *dchan)
> +{
> + struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);
> +
> + /* ASSERT: channel is idle */
> + if (axi_chan_is_hw_enable(chan))
> + dev_err(dchan2dev(dchan), "%s is non-idle!\n",
> + axi_chan_name(chan));
> +
> + axi_chan_disable(chan);
> + axi_chan_irq_disable(chan, DWAXIDMAC_IRQ_ALL);
> +
> + vchan_free_chan_resources(&chan->vc);
> +
> + dev_vdbg(dchan2dev(dchan), "%s: free resources, descriptor still allocated: %u\n",

making the string in subsequent line make it lesser than 80 chars, here and
few other places can benefit..

> +static irqreturn_t dw_axi_dma_intretupt(int irq, void *dev_id)
/s/intretupt/interrupt/ ?

> +static int axi_dma_resume(struct axi_dma_chip *chip)
> +{
> + int ret = 0;

superfluous init

> +static int parse_device_properties(struct axi_dma_chip *chip)
> +{
> + struct device *dev = chip->dev;
> + u32 tmp, carr[DMAC_MAX_CHANNELS];
> + int ret;
> +
> + ret = device_property_read_u32(dev, "dma-channels", &tmp);
> + if (ret)
> + return ret;
> + if (tmp == 0 || tmp > DMAC_MAX_CHANNELS)
> + return -EINVAL;
> +
> + chip->dw->hdata->nr_channels = tmp;
> +
> + ret = device_property_read_u32(dev, "snps,dma-masters", &tmp);

why is it snps,... shouldn't it be only dma-masters?

> +enum {
> + DWAXIDMAC_ARWLEN_1 = 0x0,
> + DWAXIDMAC_ARWLEN_2 = 0x1,
> + DWAXIDMAC_ARWLEN_4 = 0x3,
> + DWAXIDMAC_ARWLEN_8 = 0x7,
> + DWAXIDMAC_ARWLEN_16 = 0xF,
> + DWAXIDMAC_ARWLEN_32 = 0x1F,
> + DWAXIDMAC_ARWLEN_64 = 0x3F,
> + DWAXIDMAC_ARWLEN_128 = 0x7F,
> + DWAXIDMAC_ARWLEN_256 = 0xFF,

GENMASK() for these?

--
~Vinod