linux-kernel - RE: [PATCH] dmaengine: dw-edma: fix _

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Message-ID: <DM6PR12MB401058325016417472CD5717DAE70@DM6PR12MB4010.namprd12.prod.outlook.com>
Date:   Fri, 21 Jun 2019 08:53:51 +0000
From:   Gustavo Pimentel <Gustavo.Pimentel@...opsys.com>
To:     Arnd Bergmann <arnd@...db.de>,
        Gustavo Pimentel <Gustavo.Pimentel@...opsys.com>,
        Vinod Koul <vkoul@...nel.org>
CC:     Dan Williams <dan.j.williams@...el.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Russell King <rmk+kernel@...linux.org.uk>,
        Joao Pinto <Joao.Pinto@...opsys.com>,
        "dmaengine@...r.kernel.org" <dmaengine@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] dmaengine: dw-edma: fix __iomem type confusion

On Mon, Jun 17, 2019 at 14:18:43, Arnd Bergmann <arnd@...db.de> wrote:

> The new driver mixes up dma_addr_t and __iomem pointers, which results
> in warnings on some 32-bit architectures, like:
> 
> drivers/dma/dw-edma/dw-edma-v0-core.c: In function '__dw_regs':
> drivers/dma/dw-edma/dw-edma-v0-core.c:28:9: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>   return (struct dw_edma_v0_regs __iomem *)dw->rg_region.vaddr;
> 
> Make it use __iomem pointers consistently here, and avoid using dma_addr_t
> for __iomem tokens altogether.
> 
> A small complication here is the debugfs code, which passes an __iomem
> token as the private data for debugfs files, requiring the use of
> extra __force.
> 
> Fixes: 7e4b8a4fbe2c ("dmaengine: Add Synopsys eDMA IP version 0 support")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  drivers/dma/dw-edma/dw-edma-core.h       |  2 +-
>  drivers/dma/dw-edma/dw-edma-pcie.c       | 18 ++++++++--------
>  drivers/dma/dw-edma/dw-edma-v0-core.c    | 10 ++++-----
>  drivers/dma/dw-edma/dw-edma-v0-debugfs.c | 27 ++++++++++++------------
>  4 files changed, 29 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/dma/dw-edma/dw-edma-core.h b/drivers/dma/dw-edma/dw-edma-core.h
> index b6cc90cbc9dc..d03a6ad263bd 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.h
> +++ b/drivers/dma/dw-edma/dw-edma-core.h
> @@ -50,7 +50,7 @@ struct dw_edma_burst {
>  
>  struct dw_edma_region {
>  	phys_addr_t			paddr;
> -	dma_addr_t			vaddr;
> +	void __iomem *			vaddr;
>  	size_t				sz;
>  };
>  
> diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
> index 4c96e1c948f2..dc85f55e1bb8 100644
> --- a/drivers/dma/dw-edma/dw-edma-pcie.c
> +++ b/drivers/dma/dw-edma/dw-edma-pcie.c
> @@ -130,19 +130,19 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
>  	chip->id = pdev->devfn;
>  	chip->irq = pdev->irq;
>  
> -	dw->rg_region.vaddr = (dma_addr_t)pcim_iomap_table(pdev)[pdata->rg_bar];
> +	dw->rg_region.vaddr = pcim_iomap_table(pdev)[pdata->rg_bar];
>  	dw->rg_region.vaddr += pdata->rg_off;
>  	dw->rg_region.paddr = pdev->resource[pdata->rg_bar].start;
>  	dw->rg_region.paddr += pdata->rg_off;
>  	dw->rg_region.sz = pdata->rg_sz;
>  
> -	dw->ll_region.vaddr = (dma_addr_t)pcim_iomap_table(pdev)[pdata->ll_bar];
> +	dw->ll_region.vaddr = pcim_iomap_table(pdev)[pdata->ll_bar];
>  	dw->ll_region.vaddr += pdata->ll_off;
>  	dw->ll_region.paddr = pdev->resource[pdata->ll_bar].start;
>  	dw->ll_region.paddr += pdata->ll_off;
>  	dw->ll_region.sz = pdata->ll_sz;
>  
> -	dw->dt_region.vaddr = (dma_addr_t)pcim_iomap_table(pdev)[pdata->dt_bar];
> +	dw->dt_region.vaddr = pcim_iomap_table(pdev)[pdata->dt_bar];
>  	dw->dt_region.vaddr += pdata->dt_off;
>  	dw->dt_region.paddr = pdev->resource[pdata->dt_bar].start;
>  	dw->dt_region.paddr += pdata->dt_off;
> @@ -158,17 +158,17 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
>  	pci_dbg(pdev, "Mode:\t%s\n",
>  		dw->mode == EDMA_MODE_LEGACY ? "Legacy" : "Unroll");
>  
> -	pci_dbg(pdev, "Registers:\tBAR=%u, off=0x%.8lx, sz=0x%zx bytes, addr(v=%pa, p=%pa)\n",
> +	pci_dbg(pdev, "Registers:\tBAR=%u, off=0x%.8lx, sz=0x%zx bytes, addr(v=%p, p=%pa)\n",
>  		pdata->rg_bar, pdata->rg_off, pdata->rg_sz,
> -		&dw->rg_region.vaddr, &dw->rg_region.paddr);
> +		dw->rg_region.vaddr, &dw->rg_region.paddr);
>  
> -	pci_dbg(pdev, "L. List:\tBAR=%u, off=0x%.8lx, sz=0x%zx bytes, addr(v=%pa, p=%pa)\n",
> +	pci_dbg(pdev, "L. List:\tBAR=%u, off=0x%.8lx, sz=0x%zx bytes, addr(v=%p, p=%pa)\n",
>  		pdata->ll_bar, pdata->ll_off, pdata->ll_sz,
> -		&dw->ll_region.vaddr, &dw->ll_region.paddr);
> +		dw->ll_region.vaddr, &dw->ll_region.paddr);
>  
> -	pci_dbg(pdev, "Data:\tBAR=%u, off=0x%.8lx, sz=0x%zx bytes, addr(v=%pa, p=%pa)\n",
> +	pci_dbg(pdev, "Data:\tBAR=%u, off=0x%.8lx, sz=0x%zx bytes, addr(v=%p, p=%pa)\n",
>  		pdata->dt_bar, pdata->dt_off, pdata->dt_sz,
> -		&dw->dt_region.vaddr, &dw->dt_region.paddr);
> +		dw->dt_region.vaddr, &dw->dt_region.paddr);
>  
>  	pci_dbg(pdev, "Nr. IRQs:\t%u\n", dw->nr_irqs);
>  
> diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
> index 8cafd51ff9ec..d670ebcc37b3 100644
> --- a/drivers/dma/dw-edma/dw-edma-v0-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
> @@ -25,7 +25,7 @@ enum dw_edma_control {
>  
>  static inline struct dw_edma_v0_regs __iomem *__dw_regs(struct dw_edma *dw)
>  {
> -	return (struct dw_edma_v0_regs __iomem *)dw->rg_region.vaddr;
> +	return dw->rg_region.vaddr;
>  }
>  
>  #define SET(dw, name, value)				\
> @@ -192,13 +192,13 @@ u32 dw_edma_v0_core_status_abort_int(struct dw_edma *dw, enum dw_edma_dir dir)
>  static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
>  {
>  	struct dw_edma_burst *child;
> -	struct dw_edma_v0_lli *lli;
> -	struct dw_edma_v0_llp *llp;
> +	struct dw_edma_v0_lli __iomem *lli;
> +	struct dw_edma_v0_llp __iomem *llp;
>  	u32 control = 0, i = 0;
>  	uintptr_t sar, dar, addr;
>  	int j;
>  
> -	lli = (struct dw_edma_v0_lli *)chunk->ll_region.vaddr;
> +	lli = chunk->ll_region.vaddr;
>  
>  	if (chunk->cb)
>  		control = DW_EDMA_V0_CB;
> @@ -224,7 +224,7 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
>  		i++;
>  	}
>  
> -	llp = (struct dw_edma_v0_llp *)&lli[i];
> +	llp = (void __iomem *)&lli[i];
>  	control = DW_EDMA_V0_LLP | DW_EDMA_V0_TCB;
>  	if (!chunk->cb)
>  		control |= DW_EDMA_V0_CB;
> diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
> index 5728b6fe938c..42739508c0d8 100644
> --- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
> +++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
> @@ -14,7 +14,7 @@
>  #include "dw-edma-core.h"
>  
>  #define REGS_ADDR(name) \
> -	((dma_addr_t *)&regs->name)
> +	((void __force *)&regs->name)
>  #define REGISTER(name) \
>  	{ #name, REGS_ADDR(name) }
>  
> @@ -40,11 +40,11 @@
>  
>  static struct dentry				*base_dir;
>  static struct dw_edma				*dw;
> -static struct dw_edma_v0_regs			*regs;
> +static struct dw_edma_v0_regs			__iomem *regs;

Shouldn't the __iomem be next to dw_edma_v0_regs instead of the variable 
name? I saw other drivers putting the __iomem next to the variable type, 
therefore I assume it's the typical coding style.

>  
>  static struct {
> -	void					*start;
> -	void					*end;
> +	void					__iomem *start;
> +	void					__iomem *end;

Ditto.

>  } lim[2][EDMA_V0_MAX_NR_CH];
>  
>  struct debugfs_entries {
> @@ -54,22 +54,23 @@ struct debugfs_entries {
>  
>  static int dw_edma_debugfs_u32_get(void *data, u64 *val)
>  {
> +	void __iomem *reg = (void __force __iomem *)data;
>  	if (dw->mode == EDMA_MODE_LEGACY &&
> -	    data >= (void *)&regs->type.legacy.ch) {
> -		void *ptr = (void *)&regs->type.legacy.ch;
> +	    reg >= (void __iomem *)&regs->type.legacy.ch) {
> +		void __iomem *ptr = &regs->type.legacy.ch;
>  		u32 viewport_sel = 0;
>  		unsigned long flags;
>  		u16 ch;
>  
>  		for (ch = 0; ch < dw->wr_ch_cnt; ch++)
> -			if (lim[0][ch].start >= data && data < lim[0][ch].end) {
> -				ptr += (data - lim[0][ch].start);
> +			if (lim[0][ch].start >= reg && reg < lim[0][ch].end) {
> +				ptr += (reg - lim[0][ch].start);
>  				goto legacy_sel_wr;
>  			}
>  
>  		for (ch = 0; ch < dw->rd_ch_cnt; ch++)
> -			if (lim[1][ch].start >= data && data < lim[1][ch].end) {
> -				ptr += (data - lim[1][ch].start);
> +			if (lim[1][ch].start >= reg && reg < lim[1][ch].end) {
> +				ptr += (reg - lim[1][ch].start);
>  				goto legacy_sel_rd;
>  			}
>  
> @@ -86,7 +87,7 @@ static int dw_edma_debugfs_u32_get(void *data, u64 *val)
>  
>  		raw_spin_unlock_irqrestore(&dw->lock, flags);
>  	} else {
> -		*val = readl(data);
> +		*val = readl(reg);
>  	}
>  
>  	return 0;
> @@ -105,7 +106,7 @@ static void dw_edma_debugfs_create_x32(const struct debugfs_entries entries[],
>  	}
>  }
>  
> -static void dw_edma_debugfs_regs_ch(struct dw_edma_v0_ch_regs *regs,
> +static void dw_edma_debugfs_regs_ch(struct dw_edma_v0_ch_regs __iomem *regs,
>  				    struct dentry *dir)
>  {
>  	int nr_entries;
> @@ -288,7 +289,7 @@ void dw_edma_v0_debugfs_on(struct dw_edma_chip *chip)
>  	if (!dw)
>  		return;
>  
> -	regs = (struct dw_edma_v0_regs *)dw->rg_region.vaddr;
> +	regs = dw->rg_region.vaddr;
>  	if (!regs)
>  		return;
>  
> -- 
> 2.20.0