2013-07-26 11:28:54

by Cho KyongHo

Subject: [PATCH v8 08/12] iommu/exynos: remove prefetch buffer setting when enabling System MMU

Prefetch buffer must be handled accurately, exact range of a buffer,
frame by frame manually. Otherwise, it may causes page fault or
deadlock in System MMU.
Thus this patch removes prefetch buffer setting when System MMU is
initialized(enabled).

Signed-off-by: Cho KyongHo <[email protected]>
---
drivers/iommu/exynos-iommu.c | 32 +++++++++++++++++++++++++++-----
1 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index cfc02ed..87f6bb7 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -80,6 +80,8 @@
#define CTRL_BLOCK 0x7
#define CTRL_DISABLE 0x0

+#define CFG_FLPDCACHE (1 << 20) /* System MMU 3.2+ only */
+
#define REG_MMU_CTRL 0x000
#define REG_MMU_CFG 0x004
#define REG_MMU_STATUS 0x008
@@ -96,6 +98,9 @@

#define REG_MMU_VERSION 0x034

+#define MMU_MAJ_VER(reg) (reg >> 28)
+#define MMU_MIN_VER(reg) ((reg >> 21) & 0x7F)
+
#define REG_PB0_SADDR 0x04C
#define REG_PB0_EADDR 0x050
#define REG_PB1_SADDR 0x054
@@ -200,6 +205,22 @@ static bool is_sysmmu_active(struct sysmmu_drvdata *data)
return data->activations > 0;
}

+static unsigned int __sysmmu_version(struct sysmmu_drvdata *data,
+ int idx, unsigned int *minor)
+{
+ unsigned long major;
+
+ major = readl(data->sfrbases[idx] + REG_MMU_VERSION);
+
+ if (minor)
+ *minor = MMU_MIN_VER(major);
+
+ if (MMU_MAJ_VER(major) > 3)
+ return 1;
+
+ return MMU_MAJ_VER(major);
+}
+
static void sysmmu_unblock(void __iomem *sfrbase)
{
__raw_writel(CTRL_ENABLE, sfrbase + REG_MMU_CTRL);
@@ -460,14 +481,15 @@ static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
data->pgtable = pgtable;

for (i = 0; i < data->nsfrs; i++) {
+ unsigned int min;
+
__sysmmu_set_ptbase(data->sfrbases[i], pgtable);

- if ((readl(data->sfrbases[i] + REG_MMU_VERSION) >> 28) == 3) {
- /* System MMU version is 3.x */
- __raw_writel((1 << 12) | (2 << 28),
+ if ((__sysmmu_version(data, i, &min) == 3) && (min > 1)) {
+ unsigned long cfg;
+ cfg = __raw_readl(data->sfrbases[i] + REG_MMU_CFG);
+ __raw_writel(cfg | CFG_FLPDCACHE,
data->sfrbases[i] + REG_MMU_CFG);
- __sysmmu_set_prefbuf(data->sfrbases[i], 0, -1, 0);
- __sysmmu_set_prefbuf(data->sfrbases[i], 0, -1, 1);
}

__raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
--
1.7.2.5

2013-07-26 17:36:03

by Grant Grundler

Subject: Re: [PATCH v8 08/12] iommu/exynos: remove prefetch buffer setting when enabling System MMU

On Fri, Jul 26, 2013 at 4:28 AM, Cho KyongHo <[email protected]> wrote:
> Prefetch buffer must be handled accurately, exact range of a buffer,
> frame by frame manually. Otherwise, it may causes page fault or
> deadlock in System MMU.
> Thus this patch removes prefetch buffer setting when System MMU is
> initialized(enabled).
>
> Signed-off-by: Cho KyongHo <[email protected]>

Reviewed-by: Grant Grundler <[email protected]>

BTW, cscope doesn't find any callers of exynos_sysmmu_enable().
Want to submit another patch to remove it?

(Note I'm talking about exynos_sysmmu_enable() without "__" prefix).

cheers,
grant

> ---
> drivers/iommu/exynos-iommu.c | 32 +++++++++++++++++++++++++++-----
> 1 files changed, 27 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> index cfc02ed..87f6bb7 100644
> --- a/drivers/iommu/exynos-iommu.c
> +++ b/drivers/iommu/exynos-iommu.c
> @@ -80,6 +80,8 @@
> #define CTRL_BLOCK 0x7
> #define CTRL_DISABLE 0x0
>
> +#define CFG_FLPDCACHE (1 << 20) /* System MMU 3.2+ only */
> +
> #define REG_MMU_CTRL 0x000
> #define REG_MMU_CFG 0x004
> #define REG_MMU_STATUS 0x008
> @@ -96,6 +98,9 @@
>
> #define REG_MMU_VERSION 0x034
>
> +#define MMU_MAJ_VER(reg) (reg >> 28)
> +#define MMU_MIN_VER(reg) ((reg >> 21) & 0x7F)
> +
> #define REG_PB0_SADDR 0x04C
> #define REG_PB0_EADDR 0x050
> #define REG_PB1_SADDR 0x054
> @@ -200,6 +205,22 @@ static bool is_sysmmu_active(struct sysmmu_drvdata *data)
> return data->activations > 0;
> }
>
> +static unsigned int __sysmmu_version(struct sysmmu_drvdata *data,
> + int idx, unsigned int *minor)
> +{
> + unsigned long major;
> +
> + major = readl(data->sfrbases[idx] + REG_MMU_VERSION);
> +
> + if (minor)
> + *minor = MMU_MIN_VER(major);
> +
> + if (MMU_MAJ_VER(major) > 3)
> + return 1;
> +
> + return MMU_MAJ_VER(major);
> +}
> +
> static void sysmmu_unblock(void __iomem *sfrbase)
> {
> __raw_writel(CTRL_ENABLE, sfrbase + REG_MMU_CTRL);
> @@ -460,14 +481,15 @@ static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
> data->pgtable = pgtable;
>
> for (i = 0; i < data->nsfrs; i++) {
> + unsigned int min;
> +
> __sysmmu_set_ptbase(data->sfrbases[i], pgtable);
>
> - if ((readl(data->sfrbases[i] + REG_MMU_VERSION) >> 28) == 3) {
> - /* System MMU version is 3.x */
> - __raw_writel((1 << 12) | (2 << 28),
> + if ((__sysmmu_version(data, i, &min) == 3) && (min > 1)) {
> + unsigned long cfg;
> + cfg = __raw_readl(data->sfrbases[i] + REG_MMU_CFG);
> + __raw_writel(cfg | CFG_FLPDCACHE,
> data->sfrbases[i] + REG_MMU_CFG);
> - __sysmmu_set_prefbuf(data->sfrbases[i], 0, -1, 0);
> - __sysmmu_set_prefbuf(data->sfrbases[i], 0, -1, 1);
> }
>
> __raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
> --
> 1.7.2.5
>
>

2013-07-29 07:32:30

by Cho KyongHo

Subject: RE: [PATCH v8 08/12] iommu/exynos: remove prefetch buffer setting when enabling System MMU

> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of Grant Grundler
> Sent: Saturday, July 27, 2013 2:36 AM
>
> On Fri, Jul 26, 2013 at 4:28 AM, Cho KyongHo <[email protected]> wrote:
> > Prefetch buffer must be handled accurately, exact range of a buffer,
> > frame by frame manually. Otherwise, it may causes page fault or
> > deadlock in System MMU.
> > Thus this patch removes prefetch buffer setting when System MMU is
> > initialized(enabled).
> >
> > Signed-off-by: Cho KyongHo <[email protected]>
>
> Reviewed-by: Grant Grundler <[email protected]>
>
> BTW, cscope doesn't find any callers of exynos_sysmmu_enable().
> Want to submit another patch to remove it?
>
> (Note I'm talking about exynos_sysmmu_enable() without "__" prefix).

Oh, I missed removing that function.

Thank you.

>
> cheers,
> grant
>
> > ---
> > drivers/iommu/exynos-iommu.c | 32 +++++++++++++++++++++++++++-----
> > 1 files changed, 27 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> > index cfc02ed..87f6bb7 100644
> > --- a/drivers/iommu/exynos-iommu.c
> > +++ b/drivers/iommu/exynos-iommu.c
> > @@ -80,6 +80,8 @@
> > #define CTRL_BLOCK 0x7
> > #define CTRL_DISABLE 0x0
> >
> > +#define CFG_FLPDCACHE (1 << 20) /* System MMU 3.2+ only */
> > +
> > #define REG_MMU_CTRL 0x000
> > #define REG_MMU_CFG 0x004
> > #define REG_MMU_STATUS 0x008
> > @@ -96,6 +98,9 @@
> >
> > #define REG_MMU_VERSION 0x034
> >
> > +#define MMU_MAJ_VER(reg) (reg >> 28)
> > +#define MMU_MIN_VER(reg) ((reg >> 21) & 0x7F)
> > +
> > #define REG_PB0_SADDR 0x04C
> > #define REG_PB0_EADDR 0x050
> > #define REG_PB1_SADDR 0x054
> > @@ -200,6 +205,22 @@ static bool is_sysmmu_active(struct sysmmu_drvdata *data)
> > return data->activations > 0;
> > }
> >
> > +static unsigned int __sysmmu_version(struct sysmmu_drvdata *data,
> > + int idx, unsigned int *minor)
> > +{
> > + unsigned long major;
> > +
> > + major = readl(data->sfrbases[idx] + REG_MMU_VERSION);
> > +
> > + if (minor)
> > + *minor = MMU_MIN_VER(major);
> > +
> > + if (MMU_MAJ_VER(major) > 3)
> > + return 1;
> > +
> > + return MMU_MAJ_VER(major);
> > +}
> > +
> > static void sysmmu_unblock(void __iomem *sfrbase)
> > {
> > __raw_writel(CTRL_ENABLE, sfrbase + REG_MMU_CTRL);
> > @@ -460,14 +481,15 @@ static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
> > data->pgtable = pgtable;
> >
> > for (i = 0; i < data->nsfrs; i++) {
> > + unsigned int min;
> > +
> > __sysmmu_set_ptbase(data->sfrbases[i], pgtable);
> >
> > - if ((readl(data->sfrbases[i] + REG_MMU_VERSION) >> 28) == 3) {
> > - /* System MMU version is 3.x */
> > - __raw_writel((1 << 12) | (2 << 28),
> > + if ((__sysmmu_version(data, i, &min) == 3) && (min > 1)) {
> > + unsigned long cfg;
> > + cfg = __raw_readl(data->sfrbases[i] + REG_MMU_CFG);
> > + __raw_writel(cfg | CFG_FLPDCACHE,
> > data->sfrbases[i] + REG_MMU_CFG);
> > - __sysmmu_set_prefbuf(data->sfrbases[i], 0, -1, 0);
> > - __sysmmu_set_prefbuf(data->sfrbases[i], 0, -1, 1);
> > }
> >
> > __raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
> > --
> > 1.7.2.5
> >
> >