From: Robin Murphy <robin.murphy@arm.com>
To: Andrea della Porta <andrea.porta@suse.com>,
Vinod Koul <vkoul@kernel.org>,
Florian Fainelli <florian.fainelli@broadcom.com>,
Ray Jui <rjui@broadcom.com>,
Scott Branden <sbranden@broadcom.com>,
Broadcom internal kernel review list
<bcm-kernel-feedback-list@broadcom.com>,
dmaengine@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Cc: Maxime Ripard <maxime@cerno.tech>,
Dom Cobley <popcornmix@gmail.com>,
Phil Elwell <phil@raspberrypi.com>
Subject: Re: [PATCH 04/12] bcm2835-dma: Advertise the full DMA range
Date: Mon, 5 Feb 2024 17:55:03 +0000 [thread overview]
Message-ID: <1e71c153-e482-409c-b229-9b9c0662b67e@arm.com> (raw)
In-Reply-To: <a56a6d24066a64598efe4343090e51e2223475b8.1706948717.git.andrea.porta@suse.com>
On 2024-02-04 6:59 am, Andrea della Porta wrote:
> From: Phil Elwell <phil@raspberrypi.com>
>
> Unless the DMA mask is set wider than 32 bits, DMA mapping will use a
> bounce buffer.
>
> Signed-off-by: Phil Elwell <phil@raspberrypi.com>
> ---
> drivers/dma/bcm2835-dma.c | 18 +++++++++++++++---
> 1 file changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
> index 36bad198b655..237dcdb8d726 100644
> --- a/drivers/dma/bcm2835-dma.c
> +++ b/drivers/dma/bcm2835-dma.c
> @@ -39,6 +39,7 @@
> #define BCM2711_DMA_MEMCPY_CHAN 14
>
> struct bcm2835_dma_cfg_data {
> + u64 dma_mask;
> u32 chan_40bit_mask;
> };
>
> @@ -308,10 +309,12 @@ DEFINE_SPINLOCK(memcpy_lock);
>
> static const struct bcm2835_dma_cfg_data bcm2835_dma_cfg = {
> .chan_40bit_mask = 0,
> + .dma_mask = DMA_BIT_MASK(32),
> };
>
> static const struct bcm2835_dma_cfg_data bcm2711_dma_cfg = {
> .chan_40bit_mask = BIT(11) | BIT(12) | BIT(13) | BIT(14),
> + .dma_mask = DMA_BIT_MASK(36),
> };
>
> static inline size_t bcm2835_dma_max_frame_length(struct bcm2835_chan *c)
> @@ -1263,6 +1266,8 @@ static struct dma_chan *bcm2835_dma_xlate(struct of_phandle_args *spec,
>
> static int bcm2835_dma_probe(struct platform_device *pdev)
> {
> + const struct bcm2835_dma_cfg_data *cfg_data;
> + const struct of_device_id *of_id;
> struct bcm2835_dmadev *od;
> struct resource *res;
> void __iomem *base;
> @@ -1272,13 +1277,20 @@ static int bcm2835_dma_probe(struct platform_device *pdev)
> int irq_flags;
> uint32_t chans_available;
> char chan_name[BCM2835_DMA_CHAN_NAME_SIZE];
> - const struct of_device_id *of_id;
> int chan_count, chan_start, chan_end;
>
> + of_id = of_match_node(bcm2835_dma_of_match, pdev->dev.of_node);
> + if (!of_id) {
> + dev_err(&pdev->dev, "Failed to match compatible string\n");
> + return -EINVAL;
> + }
> +
> + cfg_data = of_id->data;
We've had of_device_get_match_data() for nearly 9 years now, and even a
generic device_get_match_data() for 6 ;)
> +
> if (!pdev->dev.dma_mask)
> pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
[ Passing nit: that also really shouldn't be there, especially since
cdfee5623290 ]
>
> - rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
> + rc = dma_set_mask_and_coherent(&pdev->dev, cfg_data->dma_mask);
Wait, does chan_40bit_mask mean that you still have some channels which
*can't* address this full mask? If so this can't work properly. You may
well need to redesign a bit further to have a separate DMA device for
each channel such they can each have different masks.
Thanks,
Robin.
> if (rc) {
> dev_err(&pdev->dev, "Unable to set DMA mask\n");
> return rc;
> @@ -1342,7 +1354,7 @@ static int bcm2835_dma_probe(struct platform_device *pdev)
> return -EINVAL;
> }
>
> - od->cfg_data = of_id->data;
> + od->cfg_data = cfg_data;
>
> /* Request DMA channel mask from device tree */
> if (of_property_read_u32(pdev->dev.of_node,
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next prev parent reply other threads:[~2024-02-05 17:55 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-04 6:59 [PATCH 00/12] Add support for BCM2712 DMA engine Andrea della Porta
2024-02-04 6:59 ` [PATCH 01/12] bcm2835-dma: Add support for per-channel flags Andrea della Porta
2024-02-04 6:59 ` [PATCH 02/12] bcm2835-dma: Add proper 40-bit DMA support Andrea della Porta
2024-02-05 18:50 ` Stefan Wahren
2024-02-06 16:31 ` Dave Stevenson
2024-02-06 18:08 ` Stefan Wahren
2024-02-06 18:11 ` Stefan Wahren
2024-02-04 6:59 ` [PATCH 03/12] bcm2835-dma: Add NO_WAIT_RESP, DMA_WIDE_SOURCE and DMA_WIDE_DEST flag Andrea della Porta
2024-02-04 6:59 ` [PATCH 04/12] bcm2835-dma: Advertise the full DMA range Andrea della Porta
2024-02-05 17:55 ` Robin Murphy [this message]
2024-03-01 13:55 ` Andrea della Porta
2024-02-05 18:25 ` Stefan Wahren
2024-02-04 6:59 ` [PATCH 05/12] bcm2835-dma: Derive slave DMA addresses correctly Andrea della Porta
2024-02-05 18:03 ` Robin Murphy
2024-02-04 6:59 ` [PATCH 06/12] dmaengine: bcm2835: Use to_bcm2711_cbaddr where relevant Andrea della Porta
2024-02-04 17:04 ` Florian Fainelli
2024-02-05 10:25 ` Andrea della Porta
2024-02-04 6:59 ` [PATCH 07/12] bcm2835-dma: Support dma flags for multi-beat burst Andrea della Porta
2024-02-07 8:22 ` Vinod Koul
2024-02-04 6:59 ` [PATCH 08/12] bcm2835-dma: Need to keep PROT bits set in CS on 40bit controller Andrea della Porta
2024-02-04 6:59 ` [PATCH 09/12] dmaengine: bcm2835: Add BCM2712 support Andrea della Porta
2024-02-04 6:59 ` [PATCH 10/12] dmaengine: bcm2835: Support DMA-Lite channels Andrea della Porta
2024-02-07 8:26 ` Vinod Koul
2024-02-04 6:59 ` [PATCH 11/12] dmaengine: bcm2835: Rename to_bcm2711_cbaddr to to_40bit_cbaddr Andrea della Porta
2024-02-04 6:59 ` [PATCH 12/12] bcm2835-dma: Fixes for dma_abort Andrea della Porta
2024-02-05 19:06 ` [PATCH 00/12] Add support for BCM2712 DMA engine Stefan Wahren
2024-02-07 8:19 ` Vinod Koul
2024-02-07 10:24 ` Andrea della Porta
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