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[PATCH v2 8/9] PCI: rockchip: Use u32 variable to access 32-bit registers

Rick Wertenbroek posted 9 patches 2 years, 11 months ago
There is a newer version of this series
[PATCH v2 8/9] PCI: rockchip: Use u32 variable to access 32-bit registers
Posted by Rick Wertenbroek 2 years, 11 months ago 
Previously u16 variables were used to access 32-bit registers, this
resulted in not all of the data being read from the registers. Also
the left shift of more than 16-bits would result in moving data out
of the variable. Use u32 variables to access 32-bit registers

Fixes: cf590b078391 ("PCI: rockchip: Add EP driver for Rockchip PCIe controller")
Cc: stable@vger.kernel.org
Signed-off-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
---
 drivers/pci/controller/pcie-rockchip-ep.c | 10 +++++-----
 drivers/pci/controller/pcie-rockchip.h    |  1 +
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index ca5b363ba..b7865a94e 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -292,15 +292,15 @@ static int rockchip_pcie_ep_set_msi(struct pci_epc *epc, u8 fn, u8 vfn,
 {
 	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
 	struct rockchip_pcie *rockchip = &ep->rockchip;
-	u16 flags;
+	u32 flags;
 
 	flags = rockchip_pcie_read(rockchip,
 				   ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
 				   ROCKCHIP_PCIE_EP_MSI_CTRL_REG);
 	flags &= ~ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_MASK;
 	flags |=
-	   ((multi_msg_cap << 1) <<  ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) |
-	   PCI_MSI_FLAGS_64BIT;
+	   (multi_msg_cap << ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) |
+	   (PCI_MSI_FLAGS_64BIT << ROCKCHIP_PCIE_EP_MSI_FLAGS_OFFSET);
 	flags &= ~ROCKCHIP_PCIE_EP_MSI_CTRL_MASK_MSI_CAP;
 	rockchip_pcie_write(rockchip, flags,
 			    ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
@@ -312,7 +312,7 @@ static int rockchip_pcie_ep_get_msi(struct pci_epc *epc, u8 fn, u8 vfn)
 {
 	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
 	struct rockchip_pcie *rockchip = &ep->rockchip;
-	u16 flags;
+	u32 flags;
 
 	flags = rockchip_pcie_read(rockchip,
 				   ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
@@ -374,7 +374,7 @@ static int rockchip_pcie_ep_send_msi_irq(struct rockchip_pcie_ep *ep, u8 fn,
 					 u8 interrupt_num)
 {
 	struct rockchip_pcie *rockchip = &ep->rockchip;
-	u16 flags, mme, data, data_mask;
+	u32 flags, mme, data, data_mask;
 	u8 msi_count;
 	u64 pci_addr, pci_addr_mask = 0xff;
 	u32 r;
diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h
index e90c2a2b8..11dbf53cd 100644
--- a/drivers/pci/controller/pcie-rockchip.h
+++ b/drivers/pci/controller/pcie-rockchip.h
@@ -227,6 +227,7 @@
 #define ROCKCHIP_PCIE_EP_CMD_STATUS			0x4
 #define   ROCKCHIP_PCIE_EP_CMD_STATUS_IS		BIT(19)
 #define ROCKCHIP_PCIE_EP_MSI_CTRL_REG			0x90
+#define   ROCKCHIP_PCIE_EP_MSI_FLAGS_OFFSET			16
 #define   ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET		17
 #define   ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_MASK		GENMASK(19, 17)
 #define   ROCKCHIP_PCIE_EP_MSI_CTRL_MME_OFFSET		20
-- 
2.25.1
Re: [PATCH v2 8/9] PCI: rockchip: Use u32 variable to access 32-bit registers
Posted by Damien Le Moal 2 years, 11 months ago 
On 2/14/23 23:08, Rick Wertenbroek wrote:
> Previously u16 variables were used to access 32-bit registers, this
> resulted in not all of the data being read from the registers. Also
> the left shift of more than 16-bits would result in moving data out
> of the variable. Use u32 variables to access 32-bit registers
> 
> Fixes: cf590b078391 ("PCI: rockchip: Add EP driver for Rockchip PCIe controller")
> Cc: stable@vger.kernel.org
> Signed-off-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
> ---
>  drivers/pci/controller/pcie-rockchip-ep.c | 10 +++++-----
>  drivers/pci/controller/pcie-rockchip.h    |  1 +
>  2 files changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
> index ca5b363ba..b7865a94e 100644
> --- a/drivers/pci/controller/pcie-rockchip-ep.c
> +++ b/drivers/pci/controller/pcie-rockchip-ep.c
> @@ -292,15 +292,15 @@ static int rockchip_pcie_ep_set_msi(struct pci_epc *epc, u8 fn, u8 vfn,
>  {
>  	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
>  	struct rockchip_pcie *rockchip = &ep->rockchip;
> -	u16 flags;
> +	u32 flags;
>  
>  	flags = rockchip_pcie_read(rockchip,
>  				   ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
>  				   ROCKCHIP_PCIE_EP_MSI_CTRL_REG);
>  	flags &= ~ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_MASK;
>  	flags |=
> -	   ((multi_msg_cap << 1) <<  ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) |
> -	   PCI_MSI_FLAGS_64BIT;
> +	   (multi_msg_cap << ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) |

ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET is 17 and multi_msg_cap is a u8...
Not nice.

Locally, I added the local variable:

u32 mmc = multi_msg_cap;

And use mmc instead of multi_msg_cap to avoid issues. Also,

> +	   (PCI_MSI_FLAGS_64BIT << ROCKCHIP_PCIE_EP_MSI_FLAGS_OFFSET);
>  	flags &= ~ROCKCHIP_PCIE_EP_MSI_CTRL_MASK_MSI_CAP;
>  	rockchip_pcie_write(rockchip, flags,
>  			    ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
> @@ -312,7 +312,7 @@ static int rockchip_pcie_ep_get_msi(struct pci_epc *epc, u8 fn, u8 vfn)
>  {
>  	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
>  	struct rockchip_pcie *rockchip = &ep->rockchip;
> -	u16 flags;
> +	u32 flags;
>  
>  	flags = rockchip_pcie_read(rockchip,
>  				   ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
> @@ -374,7 +374,7 @@ static int rockchip_pcie_ep_send_msi_irq(struct rockchip_pcie_ep *ep, u8 fn,
>  					 u8 interrupt_num)
>  {
>  	struct rockchip_pcie *rockchip = &ep->rockchip;
> -	u16 flags, mme, data, data_mask;
> +	u32 flags, mme, data, data_mask;
>  	u8 msi_count;
>  	u64 pci_addr, pci_addr_mask = 0xff;
>  	u32 r;
> diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h
> index e90c2a2b8..11dbf53cd 100644
> --- a/drivers/pci/controller/pcie-rockchip.h
> +++ b/drivers/pci/controller/pcie-rockchip.h
> @@ -227,6 +227,7 @@
>  #define ROCKCHIP_PCIE_EP_CMD_STATUS			0x4
>  #define   ROCKCHIP_PCIE_EP_CMD_STATUS_IS		BIT(19)
>  #define ROCKCHIP_PCIE_EP_MSI_CTRL_REG			0x90
> +#define   ROCKCHIP_PCIE_EP_MSI_FLAGS_OFFSET			16

You are not using this macro anywhere. The name is also not very
descriptive. Better have it as:

#define   ROCKCHIP_PCIE_EP_MSI_CTRL_ME		BIT(16)

to match the TRM name and be clear that the bit indicates if MSI is
enabled or not.

>  #define   ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET		17
>  #define   ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_MASK		GENMASK(19, 17)
>  #define   ROCKCHIP_PCIE_EP_MSI_CTRL_MME_OFFSET		20

-- 
Damien Le Moal
Western Digital Research
Re: [PATCH v2 8/9] PCI: rockchip: Use u32 variable to access 32-bit registers
Posted by Rick Wertenbroek 2 years, 11 months ago 
On Wed, Feb 15, 2023 at 2:34 AM Damien Le Moal
<damien.lemoal@opensource.wdc.com> wrote:
>
> On 2/14/23 23:08, Rick Wertenbroek wrote:
> > Previously u16 variables were used to access 32-bit registers, this
> > resulted in not all of the data being read from the registers. Also
> > the left shift of more than 16-bits would result in moving data out
> > of the variable. Use u32 variables to access 32-bit registers
> >
> > Fixes: cf590b078391 ("PCI: rockchip: Add EP driver for Rockchip PCIe controller")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
> > ---
> >  drivers/pci/controller/pcie-rockchip-ep.c | 10 +++++-----
> >  drivers/pci/controller/pcie-rockchip.h    |  1 +
> >  2 files changed, 6 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
> > index ca5b363ba..b7865a94e 100644
> > --- a/drivers/pci/controller/pcie-rockchip-ep.c
> > +++ b/drivers/pci/controller/pcie-rockchip-ep.c
> > @@ -292,15 +292,15 @@ static int rockchip_pcie_ep_set_msi(struct pci_epc *epc, u8 fn, u8 vfn,
> >  {
> >       struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
> >       struct rockchip_pcie *rockchip = &ep->rockchip;
> > -     u16 flags;
> > +     u32 flags;
> >
> >       flags = rockchip_pcie_read(rockchip,
> >                                  ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
> >                                  ROCKCHIP_PCIE_EP_MSI_CTRL_REG);
> >       flags &= ~ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_MASK;
> >       flags |=
> > -        ((multi_msg_cap << 1) <<  ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) |
> > -        PCI_MSI_FLAGS_64BIT;
> > +        (multi_msg_cap << ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) |
>
> ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET is 17 and multi_msg_cap is a u8...
> Not nice.
>
> Locally, I added the local variable:
>
> u32 mmc = multi_msg_cap;
>
> And use mmc instead of multi_msg_cap to avoid issues. Also,
>
> > +        (PCI_MSI_FLAGS_64BIT << ROCKCHIP_PCIE_EP_MSI_FLAGS_OFFSET);
> >       flags &= ~ROCKCHIP_PCIE_EP_MSI_CTRL_MASK_MSI_CAP;
> >       rockchip_pcie_write(rockchip, flags,
> >                           ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
> > @@ -312,7 +312,7 @@ static int rockchip_pcie_ep_get_msi(struct pci_epc *epc, u8 fn, u8 vfn)
> >  {
> >       struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
> >       struct rockchip_pcie *rockchip = &ep->rockchip;
> > -     u16 flags;
> > +     u32 flags;
> >
> >       flags = rockchip_pcie_read(rockchip,
> >                                  ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
> > @@ -374,7 +374,7 @@ static int rockchip_pcie_ep_send_msi_irq(struct rockchip_pcie_ep *ep, u8 fn,
> >                                        u8 interrupt_num)
> >  {
> >       struct rockchip_pcie *rockchip = &ep->rockchip;
> > -     u16 flags, mme, data, data_mask;
> > +     u32 flags, mme, data, data_mask;
> >       u8 msi_count;
> >       u64 pci_addr, pci_addr_mask = 0xff;
> >       u32 r;
> > diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h
> > index e90c2a2b8..11dbf53cd 100644
> > --- a/drivers/pci/controller/pcie-rockchip.h
> > +++ b/drivers/pci/controller/pcie-rockchip.h
> > @@ -227,6 +227,7 @@
> >  #define ROCKCHIP_PCIE_EP_CMD_STATUS                  0x4
> >  #define   ROCKCHIP_PCIE_EP_CMD_STATUS_IS             BIT(19)
> >  #define ROCKCHIP_PCIE_EP_MSI_CTRL_REG                        0x90
> > +#define   ROCKCHIP_PCIE_EP_MSI_FLAGS_OFFSET                  16
>
> You are not using this macro anywhere. The name is also not very
> descriptive. Better have it as:
>
> #define   ROCKCHIP_PCIE_EP_MSI_CTRL_ME          BIT(16)
>
> to match the TRM name and be clear that the bit indicates if MSI is
> enabled or not.
>

This is already the case, the #define is already there.
#define ROCKCHIP_PCIE_EP_MSI_CTRL_ME BIT(16)
The other offset is for all the MSI flags together, this offset is used
when the flags are retrieved altogether, see rockchip_pcie_ep_set_msi()
The ME bit is also used when we need to check the bit specifically, see
rockchip_pcie_ep_get_msi().

> >  #define   ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET               17
> >  #define   ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_MASK         GENMASK(19, 17)
> >  #define   ROCKCHIP_PCIE_EP_MSI_CTRL_MME_OFFSET               20
>
> --
> Damien Le Moal
> Western Digital Research
>
RE: [PATCH v2 8/9] PCI: rockchip: Use u32 variable to access 32-bit registers
Posted by David Laight 2 years, 11 months ago 
From: Damien Le Moal
> Sent: 15 February 2023 01:34
> 
> On 2/14/23 23:08, Rick Wertenbroek wrote:
> > Previously u16 variables were used to access 32-bit registers, this
> > resulted in not all of the data being read from the registers. Also
> > the left shift of more than 16-bits would result in moving data out
> > of the variable. Use u32 variables to access 32-bit registers
> >
> > Fixes: cf590b078391 ("PCI: rockchip: Add EP driver for Rockchip PCIe controller")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
> > ---
> >  drivers/pci/controller/pcie-rockchip-ep.c | 10 +++++-----
> >  drivers/pci/controller/pcie-rockchip.h    |  1 +
> >  2 files changed, 6 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
> > index ca5b363ba..b7865a94e 100644
> > --- a/drivers/pci/controller/pcie-rockchip-ep.c
> > +++ b/drivers/pci/controller/pcie-rockchip-ep.c
> > @@ -292,15 +292,15 @@ static int rockchip_pcie_ep_set_msi(struct pci_epc *epc, u8 fn, u8 vfn,
> >  {
> >  	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
> >  	struct rockchip_pcie *rockchip = &ep->rockchip;
> > -	u16 flags;
> > +	u32 flags;
> >
> >  	flags = rockchip_pcie_read(rockchip,
> >  				   ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
> >  				   ROCKCHIP_PCIE_EP_MSI_CTRL_REG);
> >  	flags &= ~ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_MASK;
> >  	flags |=
> > -	   ((multi_msg_cap << 1) <<  ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) |
> > -	   PCI_MSI_FLAGS_64BIT;
> > +	   (multi_msg_cap << ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) |
> 
> ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET is 17 and multi_msg_cap is a u8...
> Not nice.

It really doesn't matter.
As soon as you do any arithmetic char and short are promoted to int.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
Re: [PATCH v2 8/9] PCI: rockchip: Use u32 variable to access 32-bit registers
Posted by Damien Le Moal 2 years, 11 months ago 
On 2/15/23 19:46, David Laight wrote:
> From: Damien Le Moal
>> Sent: 15 February 2023 01:34
>>
>> On 2/14/23 23:08, Rick Wertenbroek wrote:
>>> Previously u16 variables were used to access 32-bit registers, this
>>> resulted in not all of the data being read from the registers. Also
>>> the left shift of more than 16-bits would result in moving data out
>>> of the variable. Use u32 variables to access 32-bit registers
>>>
>>> Fixes: cf590b078391 ("PCI: rockchip: Add EP driver for Rockchip PCIe controller")
>>> Cc: stable@vger.kernel.org
>>> Signed-off-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
>>> ---
>>>  drivers/pci/controller/pcie-rockchip-ep.c | 10 +++++-----
>>>  drivers/pci/controller/pcie-rockchip.h    |  1 +
>>>  2 files changed, 6 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
>>> index ca5b363ba..b7865a94e 100644
>>> --- a/drivers/pci/controller/pcie-rockchip-ep.c
>>> +++ b/drivers/pci/controller/pcie-rockchip-ep.c
>>> @@ -292,15 +292,15 @@ static int rockchip_pcie_ep_set_msi(struct pci_epc *epc, u8 fn, u8 vfn,
>>>  {
>>>  	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
>>>  	struct rockchip_pcie *rockchip = &ep->rockchip;
>>> -	u16 flags;
>>> +	u32 flags;
>>>
>>>  	flags = rockchip_pcie_read(rockchip,
>>>  				   ROCKCHIP_PCIE_EP_FUNC_BASE(fn) +
>>>  				   ROCKCHIP_PCIE_EP_MSI_CTRL_REG);
>>>  	flags &= ~ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_MASK;
>>>  	flags |=
>>> -	   ((multi_msg_cap << 1) <<  ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) |
>>> -	   PCI_MSI_FLAGS_64BIT;
>>> +	   (multi_msg_cap << ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) |
>>
>> ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET is 17 and multi_msg_cap is a u8...
>> Not nice.
> 
> It really doesn't matter.
> As soon as you do any arithmetic char and short are promoted to int.

OK. Thanks.


-- 
Damien Le Moal
Western Digital Research

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