Re: [PATCH] dmaengine: fsl-edma: dma map slave device address

From: Angelo Dureghello
Date: Fri Jan 18 2019 - 16:50:24 EST

Hi Laurentiu,

On Fri, Jan 18, 2019 at 12:06:23PM +0200, Laurentiu Tudor wrote:
> This mapping needs to be created in order for slave dma transfers
> to work on systems with SMMU. The implementation mostly mimics the
> one in pl330 dma driver, authored by Robin Murphy.
>
> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@xxxxxxx>
> Suggested-by: Robin Murphy <robin.murphy@xxxxxxx>
> ---
> Original approach was to add the missing mappings in the i2c client driver,
> see here for discussion: https://patchwork.ozlabs.org/patch/1026013/
>
> drivers/dma/fsl-edma-common.c | 66 ++++++++++++++++++++++++++++++++---
> drivers/dma/fsl-edma-common.h | 4 +++
> drivers/dma/fsl-edma.c | 1 +
> drivers/dma/mcf-edma.c | 1 +
> 4 files changed, 68 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/dma/fsl-edma-common.c b/drivers/dma/fsl-edma-common.c
> index 8876c4c1bb2c..0e95ee24b6d4 100644
> --- a/drivers/dma/fsl-edma-common.c
> +++ b/drivers/dma/fsl-edma-common.c
> @@ -6,6 +6,7 @@
> #include <linux/dmapool.h>
> #include <linux/module.h>
> #include <linux/slab.h>
> +#include <linux/dma-mapping.h>
>
> #include "fsl-edma-common.h"
>
> @@ -173,12 +174,62 @@ int fsl_edma_resume(struct dma_chan *chan)
> }
> EXPORT_SYMBOL_GPL(fsl_edma_resume);
>
> +static void fsl_edma_unprep_slave_dma(struct fsl_edma_chan *fsl_chan)
> +{
> + if (fsl_chan->dma_dir != DMA_NONE)
> + dma_unmap_resource(fsl_chan->vchan.chan.device->dev,
> + fsl_chan->dma_dev_addr,
> + fsl_chan->dma_dev_size,
> + fsl_chan->dma_dir, 0);
> + fsl_chan->dma_dir = DMA_NONE;
> +}
> +
> +static bool fsl_edma_prep_slave_dma(struct fsl_edma_chan *fsl_chan,
> + enum dma_transfer_direction dir)
> +{
> + struct device *dev = fsl_chan->vchan.chan.device->dev;
> + enum dma_data_direction dma_dir;
> + phys_addr_t addr = 0;
> + u32 size = 0;
> +
> + switch (dir) {
> + case DMA_MEM_TO_DEV:
> + dma_dir = DMA_FROM_DEVICE;
> + addr = fsl_chan->cfg.dst_addr;
> + size = fsl_chan->cfg.dst_maxburst;
> + break;
> + case DMA_DEV_TO_MEM:
> + dma_dir = DMA_TO_DEVICE;
> + addr = fsl_chan->cfg.src_addr;
> + size = fsl_chan->cfg.src_maxburst;
> + break;
> + default:
> + dma_dir = DMA_NONE;
> + break;
> + }
> +
> + /* Already mapped for this config? */
> + if (fsl_chan->dma_dir == dma_dir)
> + return true;
> +
> + fsl_edma_unprep_slave_dma(fsl_chan);
> +
> + fsl_chan->dma_dev_addr = dma_map_resource(dev, addr, size, dma_dir, 0);
> + if (dma_mapping_error(dev, fsl_chan->dma_dev_addr))
> + return false;
> + fsl_chan->dma_dev_size = size;
> + fsl_chan->dma_dir = dma_dir;
> +
> + return true;
> +}
> +
> int fsl_edma_slave_config(struct dma_chan *chan,
> struct dma_slave_config *cfg)
> {
> struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
>
> memcpy(&fsl_chan->cfg, cfg, sizeof(*cfg));
> + fsl_edma_unprep_slave_dma(fsl_chan);
>
> return 0;
> }
> @@ -378,6 +429,9 @@ struct dma_async_tx_descriptor *fsl_edma_prep_dma_cyclic(
> if (!is_slave_direction(direction))
> return NULL;
>
> + if (!fsl_edma_prep_slave_dma(fsl_chan, direction))
> + return NULL;
> +
> sg_len = buf_len / period_len;
> fsl_desc = fsl_edma_alloc_desc(fsl_chan, sg_len);
> if (!fsl_desc)
> @@ -409,11 +463,11 @@ struct dma_async_tx_descriptor *fsl_edma_prep_dma_cyclic(
>
> if (direction == DMA_MEM_TO_DEV) {
> src_addr = dma_buf_next;
> - dst_addr = fsl_chan->cfg.dst_addr;
> + dst_addr = fsl_chan->dma_dev_addr;
> soff = fsl_chan->cfg.dst_addr_width;
> doff = 0;
> } else {
> - src_addr = fsl_chan->cfg.src_addr;
> + src_addr = fsl_chan->dma_dev_addr;
> dst_addr = dma_buf_next;
> soff = 0;
> doff = fsl_chan->cfg.src_addr_width;
> @@ -444,6 +498,9 @@ struct dma_async_tx_descriptor *fsl_edma_prep_slave_sg(
> if (!is_slave_direction(direction))
> return NULL;
>
> + if (!fsl_edma_prep_slave_dma(fsl_chan, direction))
> + return NULL;
> +
> fsl_desc = fsl_edma_alloc_desc(fsl_chan, sg_len);
> if (!fsl_desc)
> return NULL;
> @@ -468,11 +525,11 @@ struct dma_async_tx_descriptor *fsl_edma_prep_slave_sg(
>
> if (direction == DMA_MEM_TO_DEV) {
> src_addr = sg_dma_address(sg);
> - dst_addr = fsl_chan->cfg.dst_addr;
> + dst_addr = fsl_chan->dma_dev_addr;
> soff = fsl_chan->cfg.dst_addr_width;
> doff = 0;
> } else {
> - src_addr = fsl_chan->cfg.src_addr;
> + src_addr = fsl_chan->dma_dev_addr;
> dst_addr = sg_dma_address(sg);
> soff = 0;
> doff = fsl_chan->cfg.src_addr_width;
> @@ -555,6 +612,7 @@ void fsl_edma_free_chan_resources(struct dma_chan *chan)
> fsl_edma_chan_mux(fsl_chan, 0, false);
> fsl_chan->edesc = NULL;
> vchan_get_all_descriptors(&fsl_chan->vchan, &head);
> + fsl_edma_unprep_slave_dma(fsl_chan);
> spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
>
> vchan_dma_desc_free_list(&fsl_chan->vchan, &head);
> diff --git a/drivers/dma/fsl-edma-common.h b/drivers/dma/fsl-edma-common.h
> index 8917e8865959..b435d8e1e3a1 100644
> --- a/drivers/dma/fsl-edma-common.h
> +++ b/drivers/dma/fsl-edma-common.h
> @@ -6,6 +6,7 @@
> #ifndef _FSL_EDMA_COMMON_H_
> #define _FSL_EDMA_COMMON_H_
>
> +#include <linux/dma-direction.h>
> #include "virt-dma.h"
>
> #define EDMA_CR_EDBG BIT(1)
> @@ -120,6 +121,9 @@ struct fsl_edma_chan {
> struct dma_slave_config cfg;
> u32 attr;
> struct dma_pool *tcd_pool;
> + dma_addr_t dma_dev_addr;
> + u32 dma_dev_size;
> + enum dma_data_direction dma_dir;
> };
>
> struct fsl_edma_desc {
> diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c
> index 34d70112fcc9..75e8a7ba3a22 100644
> --- a/drivers/dma/fsl-edma.c
> +++ b/drivers/dma/fsl-edma.c
> @@ -254,6 +254,7 @@ static int fsl_edma_probe(struct platform_device *pdev)
> fsl_chan->pm_state = RUNNING;
> fsl_chan->slave_id = 0;
> fsl_chan->idle = true;
> + fsl_chan->dma_dir = DMA_NONE;
> fsl_chan->vchan.desc_free = fsl_edma_free_desc;
> vchan_init(&fsl_chan->vchan, &fsl_edma->dma_dev);
>
> diff --git a/drivers/dma/mcf-edma.c b/drivers/dma/mcf-edma.c
> index 5de1b07eddff..7de54b2fafdb 100644
> --- a/drivers/dma/mcf-edma.c
> +++ b/drivers/dma/mcf-edma.c
> @@ -214,6 +214,7 @@ static int mcf_edma_probe(struct platform_device *pdev)
> mcf_chan->edma = mcf_edma;
> mcf_chan->slave_id = i;
> mcf_chan->idle = true;
> + mcf_chan->dma_dir = DMA_NONE;
> mcf_chan->vchan.desc_free = fsl_edma_free_desc;
> vchan_init(&mcf_chan->vchan, &mcf_edma->dma_dev);
> iowrite32(0x0, &regs->tcd[i].csr);
> --
> 2.17.1
>

I tested this patch on:

- Vybrid VF50N (Toradex Colibri VF50)
- ColdFire mcf54415 (Sysam stmark2 board)

and dma still works properly.

Tested-by: Angelo Dureghello <angelo@xxxxxxxx>