diff mbox series

[5/6] mips: bmips: enable RAC on BMIPS4350

Message ID 20240503135455.966-6-ansuelsmth@gmail.com (mailing list archive)
State Superseded
Headers show
Series mips: bmips: improve handling of RAC and CBR addr | expand

Commit Message

Christian Marangi May 3, 2024, 1:54 p.m. UTC 
From: Daniel González Cabanelas <dgcbueu@gmail.com>

The data RAC is left disabled by the bootloader in some SoCs, at least in
the core it boots from.
Enabling this feature increases the performance up to +30% depending on the
task.

Signed-off-by: Daniel González Cabanelas <dgcbueu@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
[ rework code and reduce code duplication ]
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 arch/mips/kernel/smp-bmips.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

Comments

Florian Fainelli May 3, 2024, 6:56 p.m. UTC | #1 
On 5/3/24 06:54, Christian Marangi wrote:
> From: Daniel González Cabanelas <dgcbueu@gmail.com>
> 
> The data RAC is left disabled by the bootloader in some SoCs, at least in
> the core it boots from.
> Enabling this feature increases the performance up to +30% depending on the
> task.
> 
> Signed-off-by: Daniel González Cabanelas <dgcbueu@gmail.com>
> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> [ rework code and reduce code duplication ]
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> ---
>   arch/mips/kernel/smp-bmips.c | 12 ++++++++++++
>   1 file changed, 12 insertions(+)
> 
> diff --git a/arch/mips/kernel/smp-bmips.c b/arch/mips/kernel/smp-bmips.c
> index 6048c471b5ee..7bde6bbaa41f 100644
> --- a/arch/mips/kernel/smp-bmips.c
> +++ b/arch/mips/kernel/smp-bmips.c
> @@ -617,6 +617,18 @@ void bmips_cpu_setup(void)
>   		__raw_readl(bmips_cbr_addr + BMIPS_RAC_ADDRESS_RANGE);
>   		break;
>   
> +	case CPU_BMIPS4350:
> +		u32 rac_addr = BMIPS_RAC_CONFIG_1;
> +
> +		if (!(read_c0_brcm_cmt_local() & (1 << 31)))
> +			rac_addr = BMIPS_RAC_CONFIG;
> +
> +		/* Enable data RAC */
> +		cfg = __raw_readl(bmips_cbr_addr + rac_addr);
> +		__raw_writel(cfg | 0xa, bmips_cbr_addr + rac_addr);

This enables data pre-fetching (bit 3) and data-caching (bit 1), have 
you tried with 0xF to see if this provides any additional speed-up?

Looks correct to me otherwise, I wonder if a flush would be in order 
right after enabling, though I did not see any specific instructions 
towards that part in the programming notes.

> +		__raw_readl(bmips_cbr_addr + rac_addr);
> +		break;
> +
>   	case CPU_BMIPS4380:
>   		/* CBG workaround for early BMIPS4380 CPUs */
>   		switch (read_c0_prid()) {
Daniel González Cabanelas May 3, 2024, 9:11 p.m. UTC | #2 
Hi Florian.
Bits 0 and 1 are already enabled by the bootloader, so no need to
write 0xF. I checked it on some devices with BCM6328, 6358, 6368 SoCs.

Example, without the patch, reading the RAC Configuration Register 0 and 1:

- BCM6368 booting from TP0:
root@OpenWrt:/# devmem 0xff400000
0x02A07015
root@OpenWrt:/# devmem 0xff400008
0x0000000F

- BCM6368 booting from TP1:
root@OpenWrt:/# devmem 0xff400000
0x02A0701F
root@OpenWrt:/# devmem 0xff400008
0x00000005
root@OpenWrt:/#

Regards.
Daniel

El vie, 3 may 2024 a las 20:56, Florian Fainelli
(<florian.fainelli@broadcom.com>) escribió:
>
> On 5/3/24 06:54, Christian Marangi wrote:
> > From: Daniel González Cabanelas <dgcbueu@gmail.com>
> >
> > The data RAC is left disabled by the bootloader in some SoCs, at least in
> > the core it boots from.
> > Enabling this feature increases the performance up to +30% depending on the
> > task.
> >
> > Signed-off-by: Daniel González Cabanelas <dgcbueu@gmail.com>
> > Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> > [ rework code and reduce code duplication ]
> > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> > ---
> >   arch/mips/kernel/smp-bmips.c | 12 ++++++++++++
> >   1 file changed, 12 insertions(+)
> >
> > diff --git a/arch/mips/kernel/smp-bmips.c b/arch/mips/kernel/smp-bmips.c
> > index 6048c471b5ee..7bde6bbaa41f 100644
> > --- a/arch/mips/kernel/smp-bmips.c
> > +++ b/arch/mips/kernel/smp-bmips.c
> > @@ -617,6 +617,18 @@ void bmips_cpu_setup(void)
> >               __raw_readl(bmips_cbr_addr + BMIPS_RAC_ADDRESS_RANGE);
> >               break;
> >
> > +     case CPU_BMIPS4350:
> > +             u32 rac_addr = BMIPS_RAC_CONFIG_1;
> > +
> > +             if (!(read_c0_brcm_cmt_local() & (1 << 31)))
> > +                     rac_addr = BMIPS_RAC_CONFIG;
> > +
> > +             /* Enable data RAC */
> > +             cfg = __raw_readl(bmips_cbr_addr + rac_addr);
> > +             __raw_writel(cfg | 0xa, bmips_cbr_addr + rac_addr);
>
> This enables data pre-fetching (bit 3) and data-caching (bit 1), have
> you tried with 0xF to see if this provides any additional speed-up?
>
> Looks correct to me otherwise, I wonder if a flush would be in order
> right after enabling, though I did not see any specific instructions
> towards that part in the programming notes.
>
> > +             __raw_readl(bmips_cbr_addr + rac_addr);
> > +             break;
> > +
> >       case CPU_BMIPS4380:
> >               /* CBG workaround for early BMIPS4380 CPUs */
> >               switch (read_c0_prid()) {
>
> --
> Florian
>
Christian Marangi May 3, 2024, 9:15 p.m. UTC | #3 
On Fri, May 03, 2024 at 11:11:13PM +0200, Daniel González Cabanelas wrote:
> El vie, 3 may 2024 a las 20:56, Florian Fainelli
> (<florian.fainelli@broadcom.com>) escribió:
> >
> > On 5/3/24 06:54, Christian Marangi wrote:
> > > From: Daniel González Cabanelas <dgcbueu@gmail.com>
> > >
> > > The data RAC is left disabled by the bootloader in some SoCs, at least in
> > > the core it boots from.
> > > Enabling this feature increases the performance up to +30% depending on the
> > > task.
> > >
> > > Signed-off-by: Daniel González Cabanelas <dgcbueu@gmail.com>
> > > Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> > > [ rework code and reduce code duplication ]
> > > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> > > ---
> > >   arch/mips/kernel/smp-bmips.c | 12 ++++++++++++
> > >   1 file changed, 12 insertions(+)
> > >
> > > diff --git a/arch/mips/kernel/smp-bmips.c b/arch/mips/kernel/smp-bmips.c
> > > index 6048c471b5ee..7bde6bbaa41f 100644
> > > --- a/arch/mips/kernel/smp-bmips.c
> > > +++ b/arch/mips/kernel/smp-bmips.c
> > > @@ -617,6 +617,18 @@ void bmips_cpu_setup(void)
> > >               __raw_readl(bmips_cbr_addr + BMIPS_RAC_ADDRESS_RANGE);
> > >               break;
> > >
> > > +     case CPU_BMIPS4350:
> > > +             u32 rac_addr = BMIPS_RAC_CONFIG_1;
> > > +
> > > +             if (!(read_c0_brcm_cmt_local() & (1 << 31)))
> > > +                     rac_addr = BMIPS_RAC_CONFIG;
> > > +
> > > +             /* Enable data RAC */
> > > +             cfg = __raw_readl(bmips_cbr_addr + rac_addr);
> > > +             __raw_writel(cfg | 0xa, bmips_cbr_addr + rac_addr);
> >
> > This enables data pre-fetching (bit 3) and data-caching (bit 1), have
> > you tried with 0xF to see if this provides any additional speed-up?
> >
> > Looks correct to me otherwise, I wonder if a flush would be in order
> > right after enabling, though I did not see any specific instructions
> > towards that part in the programming notes.
> >
> > > +             __raw_readl(bmips_cbr_addr + rac_addr);
> > > +             break;
> > > +
> > >       case CPU_BMIPS4380:
> > >               /* CBG workaround for early BMIPS4380 CPUs */
> > >               switch (read_c0_prid()) {
> >
> Hi Florian.
> Bits 0 and 1 are already enabled by the bootloader, so no need to
> write 0xF. I checked it on some devices with BCM6328, 6358, 6368 SoCs.
>
> Example, without the patch, reading the RAC Configuration Register 0 and 1:
>
> - BCM6368 booting from TP0:
> root@OpenWrt:/# devmem 0xff400000
> 0x02A07015
> root@OpenWrt:/# devmem 0xff400008
> 0x0000000F
>
> - BCM6368 booting from TP1:
> root@OpenWrt:/# devmem 0xff400000
> 0x02A0701F
> root@OpenWrt:/# devmem 0xff400008
> 0x00000005
> root@OpenWrt:/#
>

[ fixed the top-post ]

If that's the case then i'm setting 0xf since we verified it doesn't
cause problem and it's already set.
Daniel González Cabanelas May 3, 2024, 9:34 p.m. UTC | #4 
El vie, 3 may 2024 a las 23:15, Christian Marangi
(<ansuelsmth@gmail.com>) escribió:
>
> On Fri, May 03, 2024 at 11:11:13PM +0200, Daniel González Cabanelas wrote:
> > El vie, 3 may 2024 a las 20:56, Florian Fainelli
> > (<florian.fainelli@broadcom.com>) escribió:
> > >
> > > On 5/3/24 06:54, Christian Marangi wrote:
> > > > From: Daniel González Cabanelas <dgcbueu@gmail.com>
> > > >
> > > > The data RAC is left disabled by the bootloader in some SoCs, at least in
> > > > the core it boots from.
> > > > Enabling this feature increases the performance up to +30% depending on the
> > > > task.
> > > >
> > > > Signed-off-by: Daniel González Cabanelas <dgcbueu@gmail.com>
> > > > Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> > > > [ rework code and reduce code duplication ]
> > > > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> > > > ---
> > > >   arch/mips/kernel/smp-bmips.c | 12 ++++++++++++
> > > >   1 file changed, 12 insertions(+)
> > > >
> > > > diff --git a/arch/mips/kernel/smp-bmips.c b/arch/mips/kernel/smp-bmips.c
> > > > index 6048c471b5ee..7bde6bbaa41f 100644
> > > > --- a/arch/mips/kernel/smp-bmips.c
> > > > +++ b/arch/mips/kernel/smp-bmips.c
> > > > @@ -617,6 +617,18 @@ void bmips_cpu_setup(void)
> > > >               __raw_readl(bmips_cbr_addr + BMIPS_RAC_ADDRESS_RANGE);
> > > >               break;
> > > >
> > > > +     case CPU_BMIPS4350:
> > > > +             u32 rac_addr = BMIPS_RAC_CONFIG_1;
> > > > +
> > > > +             if (!(read_c0_brcm_cmt_local() & (1 << 31)))
> > > > +                     rac_addr = BMIPS_RAC_CONFIG;
> > > > +
> > > > +             /* Enable data RAC */
> > > > +             cfg = __raw_readl(bmips_cbr_addr + rac_addr);
> > > > +             __raw_writel(cfg | 0xa, bmips_cbr_addr + rac_addr);
> > >
> > > This enables data pre-fetching (bit 3) and data-caching (bit 1), have
> > > you tried with 0xF to see if this provides any additional speed-up?
> > >
> > > Looks correct to me otherwise, I wonder if a flush would be in order
> > > right after enabling, though I did not see any specific instructions
> > > towards that part in the programming notes.
> > >
> > > > +             __raw_readl(bmips_cbr_addr + rac_addr);
> > > > +             break;
> > > > +
> > > >       case CPU_BMIPS4380:
> > > >               /* CBG workaround for early BMIPS4380 CPUs */
> > > >               switch (read_c0_prid()) {
> > >
> > Hi Florian.
> > Bits 0 and 1 are already enabled by the bootloader, so no need to

I meant bits 0 and 2. These are the RAC bits:
#define RAC_FLH         (1 << 8)
#define RAC_DPF         (1 << 6)
#define RAC_NCH         (1 << 5)
#define RAC_C_INV       (1 << 4)
#define RAC_PF_D        (1 << 3)
#define RAC_PF_I        (1 << 2)
#define RAC_D           (1 << 1)
#define RAC_I           (1 << 0)

> > write 0xF. I checked it on some devices with BCM6328, 6358, 6368 SoCs.
> >
> > Example, without the patch, reading the RAC Configuration Register 0 and 1:
> >
> > - BCM6368 booting from TP0:
> > root@OpenWrt:/# devmem 0xff400000
> > 0x02A07015
> > root@OpenWrt:/# devmem 0xff400008
> > 0x0000000F
> >
> > - BCM6368 booting from TP1:
> > root@OpenWrt:/# devmem 0xff400000
> > 0x02A0701F
> > root@OpenWrt:/# devmem 0xff400008
> > 0x00000005
> > root@OpenWrt:/#
> >
>
> [ fixed the top-post ]
>
> If that's the case then i'm setting 0xf since we verified it doesn't
> cause problem and it's already set.

It's harmless to re-enable the instruction bits. BTW the log commit
refers only to data RAC, 0xF is enabling both the data and instruction
RAC.

Daniel
>
> --
>         Ansuel
diff mbox series

Patch

diff --git a/arch/mips/kernel/smp-bmips.c b/arch/mips/kernel/smp-bmips.c
index 6048c471b5ee..7bde6bbaa41f 100644
--- a/arch/mips/kernel/smp-bmips.c
+++ b/arch/mips/kernel/smp-bmips.c
@@ -617,6 +617,18 @@  void bmips_cpu_setup(void)
 		__raw_readl(bmips_cbr_addr + BMIPS_RAC_ADDRESS_RANGE);
 		break;
 
+	case CPU_BMIPS4350:
+		u32 rac_addr = BMIPS_RAC_CONFIG_1;
+
+		if (!(read_c0_brcm_cmt_local() & (1 << 31)))
+			rac_addr = BMIPS_RAC_CONFIG;
+
+		/* Enable data RAC */
+		cfg = __raw_readl(bmips_cbr_addr + rac_addr);
+		__raw_writel(cfg | 0xa, bmips_cbr_addr + rac_addr);
+		__raw_readl(bmips_cbr_addr + rac_addr);
+		break;
+
 	case CPU_BMIPS4380:
 		/* CBG workaround for early BMIPS4380 CPUs */
 		switch (read_c0_prid()) {