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From:   Gustavo Pimentel <Gustavo.Pimentel@synopsys.com>
To:     Arnd Bergmann <arnd@arndb.de>,
        Gustavo Pimentel <Gustavo.Pimentel@synopsys.com>,
        Vinod Koul <vkoul@kernel.org>
CC:     Dan Williams <dan.j.williams@intel.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Russell King <rmk+kernel@armlinux.org.uk>,
        Joao Pinto <Joao.Pinto@synopsys.com>,
        "dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] dmaengine: dw-edma: fix __iomem type confusion
Thread-Topic: [PATCH] dmaengine: dw-edma: fix __iomem type confusion
Thread-Index: AQHVJQ9kwKPy1knRjkS259Lqkv5E76al0Lgw
Date:   Fri, 21 Jun 2019 08:53:51 +0000
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References: <20190617131918.2518727-1-arnd@arndb.de>
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On Mon, Jun 17, 2019 at 14:18:43, Arnd Bergmann <arnd@arndb.de> wrote:

> The new driver mixes up dma_addr_t and __iomem pointers, which results
> in warnings on some 32-bit architectures, like:
>=20
> 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 i=
nteger of different size [-Werror=3Dint-to-pointer-cast]
>   return (struct dw_edma_v0_regs __iomem *)dw->rg_region.vaddr;
>=20
> Make it use __iomem pointers consistently here, and avoid using dma_addr_=
t
> for __iomem tokens altogether.
>=20
> 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.
>=20
> Fixes: 7e4b8a4fbe2c ("dmaengine: Add Synopsys eDMA IP version 0 support")
> Signed-off-by: Arnd Bergmann <arnd@arndb.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(-)
>=20
> 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 {
> =20
>  struct dw_edma_region {
>  	phys_addr_t			paddr;
> -	dma_addr_t			vaddr;
> +	void __iomem *			vaddr;
>  	size_t				sz;
>  };
> =20
> 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 =3D pdev->devfn;
>  	chip->irq =3D pdev->irq;
> =20
> -	dw->rg_region.vaddr =3D (dma_addr_t)pcim_iomap_table(pdev)[pdata->rg_ba=
r];
> +	dw->rg_region.vaddr =3D pcim_iomap_table(pdev)[pdata->rg_bar];
>  	dw->rg_region.vaddr +=3D pdata->rg_off;
>  	dw->rg_region.paddr =3D pdev->resource[pdata->rg_bar].start;
>  	dw->rg_region.paddr +=3D pdata->rg_off;
>  	dw->rg_region.sz =3D pdata->rg_sz;
> =20
> -	dw->ll_region.vaddr =3D (dma_addr_t)pcim_iomap_table(pdev)[pdata->ll_ba=
r];
> +	dw->ll_region.vaddr =3D pcim_iomap_table(pdev)[pdata->ll_bar];
>  	dw->ll_region.vaddr +=3D pdata->ll_off;
>  	dw->ll_region.paddr =3D pdev->resource[pdata->ll_bar].start;
>  	dw->ll_region.paddr +=3D pdata->ll_off;
>  	dw->ll_region.sz =3D pdata->ll_sz;
> =20
> -	dw->dt_region.vaddr =3D (dma_addr_t)pcim_iomap_table(pdev)[pdata->dt_ba=
r];
> +	dw->dt_region.vaddr =3D pcim_iomap_table(pdev)[pdata->dt_bar];
>  	dw->dt_region.vaddr +=3D pdata->dt_off;
>  	dw->dt_region.paddr =3D pdev->resource[pdata->dt_bar].start;
>  	dw->dt_region.paddr +=3D 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 =3D=3D EDMA_MODE_LEGACY ? "Legacy" : "Unroll");
> =20
> -	pci_dbg(pdev, "Registers:\tBAR=3D%u, off=3D0x%.8lx, sz=3D0x%zx bytes, a=
ddr(v=3D%pa, p=3D%pa)\n",
> +	pci_dbg(pdev, "Registers:\tBAR=3D%u, off=3D0x%.8lx, sz=3D0x%zx bytes, a=
ddr(v=3D%p, p=3D%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);
> =20
> -	pci_dbg(pdev, "L. List:\tBAR=3D%u, off=3D0x%.8lx, sz=3D0x%zx bytes, add=
r(v=3D%pa, p=3D%pa)\n",
> +	pci_dbg(pdev, "L. List:\tBAR=3D%u, off=3D0x%.8lx, sz=3D0x%zx bytes, add=
r(v=3D%p, p=3D%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);
> =20
> -	pci_dbg(pdev, "Data:\tBAR=3D%u, off=3D0x%.8lx, sz=3D0x%zx bytes, addr(v=
=3D%pa, p=3D%pa)\n",
> +	pci_dbg(pdev, "Data:\tBAR=3D%u, off=3D0x%.8lx, sz=3D0x%zx bytes, addr(v=
=3D%p, p=3D%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);
> =20
>  	pci_dbg(pdev, "Nr. IRQs:\t%u\n", dw->nr_irqs);
> =20
> 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 {
> =20
>  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;
>  }
> =20
>  #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 =3D 0, i =3D 0;
>  	uintptr_t sar, dar, addr;
>  	int j;
> =20
> -	lli =3D (struct dw_edma_v0_lli *)chunk->ll_region.vaddr;
> +	lli =3D chunk->ll_region.vaddr;
> =20
>  	if (chunk->cb)
>  		control =3D DW_EDMA_V0_CB;
> @@ -224,7 +224,7 @@ static void dw_edma_v0_core_write_chunk(struct dw_edm=
a_chunk *chunk)
>  		i++;
>  	}
> =20
> -	llp =3D (struct dw_edma_v0_llp *)&lli[i];
> +	llp =3D (void __iomem *)&lli[i];
>  	control =3D DW_EDMA_V0_LLP | DW_EDMA_V0_TCB;
>  	if (!chunk->cb)
>  		control |=3D DW_EDMA_V0_CB;
> diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-ed=
ma/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"
> =20
>  #define REGS_ADDR(name) \
> -	((dma_addr_t *)&regs->name)
> +	((void __force *)&regs->name)
>  #define REGISTER(name) \
>  	{ #name, REGS_ADDR(name) }
> =20
> @@ -40,11 +40,11 @@
> =20
>  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=20
name? I saw other drivers putting the __iomem next to the variable type,=20
therefore I assume it's the typical coding style.

> =20
>  static struct {
> -	void					*start;
> -	void					*end;
> +	void					__iomem *start;
> +	void					__iomem *end;

Ditto.

>  } lim[2][EDMA_V0_MAX_NR_CH];
> =20
>  struct debugfs_entries {
> @@ -54,22 +54,23 @@ struct debugfs_entries {
> =20
>  static int dw_edma_debugfs_u32_get(void *data, u64 *val)
>  {
> +	void __iomem *reg =3D (void __force __iomem *)data;
>  	if (dw->mode =3D=3D EDMA_MODE_LEGACY &&
> -	    data >=3D (void *)&regs->type.legacy.ch) {
> -		void *ptr =3D (void *)&regs->type.legacy.ch;
> +	    reg >=3D (void __iomem *)&regs->type.legacy.ch) {
> +		void __iomem *ptr =3D &regs->type.legacy.ch;
>  		u32 viewport_sel =3D 0;
>  		unsigned long flags;
>  		u16 ch;
> =20
>  		for (ch =3D 0; ch < dw->wr_ch_cnt; ch++)
> -			if (lim[0][ch].start >=3D data && data < lim[0][ch].end) {
> -				ptr +=3D (data - lim[0][ch].start);
> +			if (lim[0][ch].start >=3D reg && reg < lim[0][ch].end) {
> +				ptr +=3D (reg - lim[0][ch].start);
>  				goto legacy_sel_wr;
>  			}
> =20
>  		for (ch =3D 0; ch < dw->rd_ch_cnt; ch++)
> -			if (lim[1][ch].start >=3D data && data < lim[1][ch].end) {
> -				ptr +=3D (data - lim[1][ch].start);
> +			if (lim[1][ch].start >=3D reg && reg < lim[1][ch].end) {
> +				ptr +=3D (reg - lim[1][ch].start);
>  				goto legacy_sel_rd;
>  			}
> =20
> @@ -86,7 +87,7 @@ static int dw_edma_debugfs_u32_get(void *data, u64 *val=
)
> =20
>  		raw_spin_unlock_irqrestore(&dw->lock, flags);
>  	} else {
> -		*val =3D readl(data);
> +		*val =3D readl(reg);
>  	}
> =20
>  	return 0;
> @@ -105,7 +106,7 @@ static void dw_edma_debugfs_create_x32(const struct d=
ebugfs_entries entries[],
>  	}
>  }
> =20
> -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 *r=
egs,
>  				    struct dentry *dir)
>  {
>  	int nr_entries;
> @@ -288,7 +289,7 @@ void dw_edma_v0_debugfs_on(struct dw_edma_chip *chip)
>  	if (!dw)
>  		return;
> =20
> -	regs =3D (struct dw_edma_v0_regs *)dw->rg_region.vaddr;
> +	regs =3D dw->rg_region.vaddr;
>  	if (!regs)
>  		return;
> =20
> --=20
> 2.20.0