Re: [RESEND PATCH v4] iommu/mediatek: check 4GB mode by reading infracfg

2020-08-29 Thread Miles Chen 
On Thu, 2020-08-27 at 20:27 +0100, Robin Murphy wrote:
> On 2020-08-27 06:31, Yong Wu wrote:
> > On Wed, 2020-08-26 at 16:56 +0800, Miles Chen wrote:
> >> In previous discussion [1] and [2], we found that it is risky to
> >> use max_pfn or totalram_pages to tell if 4GB mode is enabled.
> >>
> >> Check 4GB mode by reading infracfg register, remove the usage
> >> of the un-exported symbol max_pfn.
> >>
> >> This is a step towards building mtk_iommu as a kernel module.
> >>
> >> [1] 
> >> https://lore.kernel.org/lkml/20200603161132.2441-1-miles.c...@mediatek.com/
> >> [2] 
> >> https://lore.kernel.org/lkml/20200604080120.2628-1-miles.c...@mediatek.com/
> >> [3] https://lore.kernel.org/lkml/20200715205120.GA778876@bogus/
> >>
> >> Cc: Mike Rapoport 
> >> Cc: David Hildenbrand 
> >> Cc: Yong Wu 
> >> Cc: Yingjoe Chen 
> >> Cc: Christoph Hellwig 
> >> Cc: Rob Herring 
> >> Cc: Matthias Brugger 
> >> Signed-off-by: Miles Chen 
> >>
> >> ---
> >>
> >> Change since v3
> >> - use lore.kernel.org links
> >> - move "change since..." after "---"
> >>
> >> Change since v2:
> >> - determine compatible string by m4u_plat
> >> - rebase to next-20200720
> >> - add "---"
> >>
> >> Change since v1:
> >> - remove the phandle usage, search for infracfg instead [3]
> >> - use infracfg instead of infracfg_regmap
> >> - move infracfg definitaions to linux/soc/mediatek/infracfg.h
> >> - update enable_4GB only when has_4gb_mode
> >> ---
> >>   drivers/iommu/mtk_iommu.c | 34 +++
> >>   include/linux/soc/mediatek/infracfg.h |  3 +++
> >>   2 files changed, 32 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> >> index 785b228d39a6..adc350150492 100644
> >> --- a/drivers/iommu/mtk_iommu.c
> >> +++ b/drivers/iommu/mtk_iommu.c
> >> @@ -3,7 +3,6 @@
> >>* Copyright (c) 2015-2016 MediaTek Inc.
> >>* Author: Yong Wu 
> >>*/
> >> -#include 
> >>   #include 
> >>   #include 
> >>   #include 
> >> @@ -15,13 +14,16 @@
> >>   #include 
> >>   #include 
> >>   #include 
> >> +#include 
> >>   #include 
> >>   #include 
> >>   #include 
> >>   #include 
> >>   #include 
> >> +#include 
> >>   #include 
> >>   #include 
> >> +#include 
> >>   #include 
> >>   #include 
> >>   
> >> @@ -640,8 +642,11 @@ static int mtk_iommu_probe(struct platform_device 
> >> *pdev)
> >>struct resource *res;
> >>resource_size_t ioaddr;
> >>struct component_match  *match = NULL;
> >> +  struct regmap   *infracfg;
> >>void*protect;
> >>int i, larb_nr, ret;
> >> +  u32 val;
> >> +  char*p;
> >>   
> >>data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> >>if (!data)
> >> @@ -655,10 +660,29 @@ static int mtk_iommu_probe(struct platform_device 
> >> *pdev)
> >>return -ENOMEM;
> >>data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN);
> >>   
> >> -  /* Whether the current dram is over 4GB */
> >> -  data->enable_4GB = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT));
> >> -  if (!MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE))
> >> -  data->enable_4GB = false;
> >> +  data->enable_4GB = false;
> 
> Nit: this isn't really necessary, since the structure is kzalloc()ed.

Thanks for the comment, I will remove this this in v5.
> 
> >> +  if (MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE)) {
> >> +  switch (data->plat_data->m4u_plat) {
> >> +  case M4U_MT2712:
> >> +  p = "mediatek,mt2712-infracfg";
> >> +  break;
> >> +  case M4U_MT8173:
> >> +  p = "mediatek,mt8173-infracfg";
> >> +  break;
> >> +  default:
> >> +  p = NULL;
> >> +  }
> >> +
> > 
> > This can be simplified:
> > 
> >  if (data->plat_data->m4u_plat == M4U_MT2712)
> > p = "mediatek,mt2712-infracfg";
> > else if(data->plat_data->m4u_plat == M4U_MT8173)
> > p = "mediatek,mt8173-infracfg";
> > else
> > return -EINVAL;
> 
> Right, at this point the HAS_4GB_MODE flag is entirely redundant and 
> should be removed. FWIW I still think your suggestion of putting the 
> infracfg names into plat_data would be even better and cleaner - there's 
> plenty of precedent for that sort of thing (see "git grep '\.clk_name'" 
> for example).
> 
> Robin.

hmm, I have no strong opinion about this. We have discussed this
approach before and built this patch based on the discussion.
https://lore.kernel.org/patchwork/patch/1276801/



Miles
> 
> > 
> > Then,
> > Reviewed-by: Yong Wu 
> > 
> > 
> >> +  infracfg = syscon_regmap_lookup_by_compatible(p);
> >> +
> >> +  if (IS_ERR(infracfg))
> >> +  return PTR_ERR(infracfg);
> >> +
> >> +  ret = regmap_read(infracfg, REG_INFRA_MISC, );
> >> +  if (ret)
> >> +  return ret;
> >> +

Re: [RESEND PATCH v4] iommu/mediatek: check 4GB mode by reading infracfg

2020-08-27 Thread Robin Murphy 

On 2020-08-27 06:31, Yong Wu wrote:

On Wed, 2020-08-26 at 16:56 +0800, Miles Chen wrote:

In previous discussion [1] and [2], we found that it is risky to
use max_pfn or totalram_pages to tell if 4GB mode is enabled.

Check 4GB mode by reading infracfg register, remove the usage
of the un-exported symbol max_pfn.

This is a step towards building mtk_iommu as a kernel module.

[1] https://lore.kernel.org/lkml/20200603161132.2441-1-miles.c...@mediatek.com/
[2] https://lore.kernel.org/lkml/20200604080120.2628-1-miles.c...@mediatek.com/
[3] https://lore.kernel.org/lkml/20200715205120.GA778876@bogus/

Cc: Mike Rapoport 
Cc: David Hildenbrand 
Cc: Yong Wu 
Cc: Yingjoe Chen 
Cc: Christoph Hellwig 
Cc: Rob Herring 
Cc: Matthias Brugger 
Signed-off-by: Miles Chen 

---

Change since v3
- use lore.kernel.org links
- move "change since..." after "---"

Change since v2:
- determine compatible string by m4u_plat
- rebase to next-20200720
- add "---"

Change since v1:
- remove the phandle usage, search for infracfg instead [3]
- use infracfg instead of infracfg_regmap
- move infracfg definitaions to linux/soc/mediatek/infracfg.h
- update enable_4GB only when has_4gb_mode
---
  drivers/iommu/mtk_iommu.c | 34 +++
  include/linux/soc/mediatek/infracfg.h |  3 +++
  2 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 785b228d39a6..adc350150492 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -3,7 +3,6 @@
   * Copyright (c) 2015-2016 MediaTek Inc.
   * Author: Yong Wu 
   */
-#include 
  #include 
  #include 
  #include 
@@ -15,13 +14,16 @@
  #include 
  #include 
  #include 
+#include 
  #include 
  #include 
  #include 
  #include 
  #include 
+#include 
  #include 
  #include 
+#include 
  #include 
  #include 
  
@@ -640,8 +642,11 @@ static int mtk_iommu_probe(struct platform_device *pdev)

struct resource *res;
resource_size_t ioaddr;
struct component_match  *match = NULL;
+   struct regmap   *infracfg;
void*protect;
int i, larb_nr, ret;
+   u32 val;
+   char*p;
  
  	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);

if (!data)
@@ -655,10 +660,29 @@ static int mtk_iommu_probe(struct platform_device *pdev)
return -ENOMEM;
data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN);
  
-	/* Whether the current dram is over 4GB */

-   data->enable_4GB = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT));
-   if (!MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE))
-   data->enable_4GB = false;
+   data->enable_4GB = false;


Nit: this isn't really necessary, since the structure is kzalloc()ed.


+   if (MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE)) {
+   switch (data->plat_data->m4u_plat) {
+   case M4U_MT2712:
+   p = "mediatek,mt2712-infracfg";
+   break;
+   case M4U_MT8173:
+   p = "mediatek,mt8173-infracfg";
+   break;
+   default:
+   p = NULL;
+   }
+


This can be simplified:

 if (data->plat_data->m4u_plat == M4U_MT2712)
p = "mediatek,mt2712-infracfg";
else if(data->plat_data->m4u_plat == M4U_MT8173)
p = "mediatek,mt8173-infracfg";
else
return -EINVAL;


Right, at this point the HAS_4GB_MODE flag is entirely redundant and 
should be removed. FWIW I still think your suggestion of putting the 
infracfg names into plat_data would be even better and cleaner - there's 
plenty of precedent for that sort of thing (see "git grep '\.clk_name'" 
for example).


Robin.



Then,
Reviewed-by: Yong Wu 



+   infracfg = syscon_regmap_lookup_by_compatible(p);
+
+   if (IS_ERR(infracfg))
+   return PTR_ERR(infracfg);
+
+   ret = regmap_read(infracfg, REG_INFRA_MISC, );
+   if (ret)
+   return ret;
+   data->enable_4GB = !!(val & F_DDR_4GB_SUPPORT_EN);
+   }
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

data->base = devm_ioremap_resource(dev, res);
diff --git a/include/linux/soc/mediatek/infracfg.h 
b/include/linux/soc/mediatek/infracfg.h
index fd25f0148566..233463d789c6 100644
--- a/include/linux/soc/mediatek/infracfg.h
+++ b/include/linux/soc/mediatek/infracfg.h
@@ -32,6 +32,9 @@
  #define MT7622_TOP_AXI_PROT_EN_WB (BIT(2) | BIT(6) | \
 BIT(7) | BIT(8))
  
+#define REG_INFRA_MISC0xf00

+#define F_DDR_4GB_SUPPORT_EN   BIT(13)
+
  int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask,
bool reg_update);

Re: [RESEND PATCH v4] iommu/mediatek: check 4GB mode by reading infracfg

2020-08-27 Thread Matthias Brugger 




On 26/08/2020 10:56, Miles Chen wrote:

In previous discussion [1] and [2], we found that it is risky to
use max_pfn or totalram_pages to tell if 4GB mode is enabled.

Check 4GB mode by reading infracfg register, remove the usage
of the un-exported symbol max_pfn.

This is a step towards building mtk_iommu as a kernel module.

[1] https://lore.kernel.org/lkml/20200603161132.2441-1-miles.c...@mediatek.com/
[2] https://lore.kernel.org/lkml/20200604080120.2628-1-miles.c...@mediatek.com/
[3] https://lore.kernel.org/lkml/20200715205120.GA778876@bogus/

Cc: Mike Rapoport 
Cc: David Hildenbrand 
Cc: Yong Wu 
Cc: Yingjoe Chen 
Cc: Christoph Hellwig 
Cc: Rob Herring 
Cc: Matthias Brugger 
Signed-off-by: Miles Chen 


Reviewed-by: Matthias Brugger 



---

Change since v3
- use lore.kernel.org links
- move "change since..." after "---"

Change since v2:
- determine compatible string by m4u_plat
- rebase to next-20200720
- add "---"

Change since v1:
- remove the phandle usage, search for infracfg instead [3]
- use infracfg instead of infracfg_regmap
- move infracfg definitaions to linux/soc/mediatek/infracfg.h
- update enable_4GB only when has_4gb_mode
---
  drivers/iommu/mtk_iommu.c | 34 +++
  include/linux/soc/mediatek/infracfg.h |  3 +++
  2 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 785b228d39a6..adc350150492 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -3,7 +3,6 @@
   * Copyright (c) 2015-2016 MediaTek Inc.
   * Author: Yong Wu 
   */
-#include 
  #include 
  #include 
  #include 
@@ -15,13 +14,16 @@
  #include 
  #include 
  #include 
+#include 
  #include 
  #include 
  #include 
  #include 
  #include 
+#include 
  #include 
  #include 
+#include 
  #include 
  #include 
  
@@ -640,8 +642,11 @@ static int mtk_iommu_probe(struct platform_device *pdev)

struct resource *res;
resource_size_t ioaddr;
struct component_match  *match = NULL;
+   struct regmap   *infracfg;
void*protect;
int i, larb_nr, ret;
+   u32 val;
+   char*p;
  
  	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);

if (!data)
@@ -655,10 +660,29 @@ static int mtk_iommu_probe(struct platform_device *pdev)
return -ENOMEM;
data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN);
  
-	/* Whether the current dram is over 4GB */

-   data->enable_4GB = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT));
-   if (!MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE))
-   data->enable_4GB = false;
+   data->enable_4GB = false;
+   if (MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE)) {
+   switch (data->plat_data->m4u_plat) {
+   case M4U_MT2712:
+   p = "mediatek,mt2712-infracfg";
+   break;
+   case M4U_MT8173:
+   p = "mediatek,mt8173-infracfg";
+   break;
+   default:
+   p = NULL;
+   }
+
+   infracfg = syscon_regmap_lookup_by_compatible(p);
+
+   if (IS_ERR(infracfg))
+   return PTR_ERR(infracfg);
+
+   ret = regmap_read(infracfg, REG_INFRA_MISC, );
+   if (ret)
+   return ret;
+   data->enable_4GB = !!(val & F_DDR_4GB_SUPPORT_EN);
+   }
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

data->base = devm_ioremap_resource(dev, res);
diff --git a/include/linux/soc/mediatek/infracfg.h 
b/include/linux/soc/mediatek/infracfg.h
index fd25f0148566..233463d789c6 100644
--- a/include/linux/soc/mediatek/infracfg.h
+++ b/include/linux/soc/mediatek/infracfg.h
@@ -32,6 +32,9 @@
  #define MT7622_TOP_AXI_PROT_EN_WB (BIT(2) | BIT(6) | \
 BIT(7) | BIT(8))
  
+#define REG_INFRA_MISC0xf00

+#define F_DDR_4GB_SUPPORT_EN   BIT(13)
+
  int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask,
bool reg_update);
  int mtk_infracfg_clear_bus_protection(struct regmap *infracfg, u32 mask,


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Re: [RESEND PATCH v4] iommu/mediatek: check 4GB mode by reading infracfg

2020-08-26 Thread Yong Wu 
On Wed, 2020-08-26 at 16:56 +0800, Miles Chen wrote:
> In previous discussion [1] and [2], we found that it is risky to
> use max_pfn or totalram_pages to tell if 4GB mode is enabled.
> 
> Check 4GB mode by reading infracfg register, remove the usage
> of the un-exported symbol max_pfn.
> 
> This is a step towards building mtk_iommu as a kernel module.
> 
> [1] 
> https://lore.kernel.org/lkml/20200603161132.2441-1-miles.c...@mediatek.com/
> [2] 
> https://lore.kernel.org/lkml/20200604080120.2628-1-miles.c...@mediatek.com/
> [3] https://lore.kernel.org/lkml/20200715205120.GA778876@bogus/
> 
> Cc: Mike Rapoport 
> Cc: David Hildenbrand 
> Cc: Yong Wu 
> Cc: Yingjoe Chen 
> Cc: Christoph Hellwig 
> Cc: Rob Herring 
> Cc: Matthias Brugger 
> Signed-off-by: Miles Chen 
> 
> ---
> 
> Change since v3
> - use lore.kernel.org links
> - move "change since..." after "---"
> 
> Change since v2:
> - determine compatible string by m4u_plat
> - rebase to next-20200720
> - add "---"
> 
> Change since v1:
> - remove the phandle usage, search for infracfg instead [3]
> - use infracfg instead of infracfg_regmap
> - move infracfg definitaions to linux/soc/mediatek/infracfg.h
> - update enable_4GB only when has_4gb_mode
> ---
>  drivers/iommu/mtk_iommu.c | 34 +++
>  include/linux/soc/mediatek/infracfg.h |  3 +++
>  2 files changed, 32 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 785b228d39a6..adc350150492 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -3,7 +3,6 @@
>   * Copyright (c) 2015-2016 MediaTek Inc.
>   * Author: Yong Wu 
>   */
> -#include 
>  #include 
>  #include 
>  #include 
> @@ -15,13 +14,16 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  #include 
>  #include 
>  #include 
>  #include 
>  #include 
> +#include 
>  #include 
>  #include 
> +#include 
>  #include 
>  #include 
>  
> @@ -640,8 +642,11 @@ static int mtk_iommu_probe(struct platform_device *pdev)
>   struct resource *res;
>   resource_size_t ioaddr;
>   struct component_match  *match = NULL;
> + struct regmap   *infracfg;
>   void*protect;
>   int i, larb_nr, ret;
> + u32 val;
> + char*p;
>  
>   data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
>   if (!data)
> @@ -655,10 +660,29 @@ static int mtk_iommu_probe(struct platform_device *pdev)
>   return -ENOMEM;
>   data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN);
>  
> - /* Whether the current dram is over 4GB */
> - data->enable_4GB = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT));
> - if (!MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE))
> - data->enable_4GB = false;
> + data->enable_4GB = false;
> + if (MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE)) {
> + switch (data->plat_data->m4u_plat) {
> + case M4U_MT2712:
> + p = "mediatek,mt2712-infracfg";
> + break;
> + case M4U_MT8173:
> + p = "mediatek,mt8173-infracfg";
> + break;
> + default:
> + p = NULL;
> + }
> +

This can be simplified:

if (data->plat_data->m4u_plat == M4U_MT2712)
p = "mediatek,mt2712-infracfg";
else if(data->plat_data->m4u_plat == M4U_MT8173)
p = "mediatek,mt8173-infracfg";
else
return -EINVAL;

Then,
Reviewed-by: Yong Wu 


> + infracfg = syscon_regmap_lookup_by_compatible(p);
> +
> + if (IS_ERR(infracfg))
> + return PTR_ERR(infracfg);
> +
> + ret = regmap_read(infracfg, REG_INFRA_MISC, );
> + if (ret)
> + return ret;
> + data->enable_4GB = !!(val & F_DDR_4GB_SUPPORT_EN);
> + }
>  
>   res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>   data->base = devm_ioremap_resource(dev, res);
> diff --git a/include/linux/soc/mediatek/infracfg.h 
> b/include/linux/soc/mediatek/infracfg.h
> index fd25f0148566..233463d789c6 100644
> --- a/include/linux/soc/mediatek/infracfg.h
> +++ b/include/linux/soc/mediatek/infracfg.h
> @@ -32,6 +32,9 @@
>  #define MT7622_TOP_AXI_PROT_EN_WB(BIT(2) | BIT(6) | \
>BIT(7) | BIT(8))
>  
> +#define REG_INFRA_MISC   0xf00
> +#define F_DDR_4GB_SUPPORT_EN BIT(13)
> +
>  int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask,
>   bool reg_update);
>  int mtk_infracfg_clear_bus_protection(struct regmap *infracfg, u32 mask,

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[RESEND PATCH v4] iommu/mediatek: check 4GB mode by reading infracfg

2020-08-26 Thread Miles Chen 
In previous discussion [1] and [2], we found that it is risky to
use max_pfn or totalram_pages to tell if 4GB mode is enabled.

Check 4GB mode by reading infracfg register, remove the usage
of the un-exported symbol max_pfn.

This is a step towards building mtk_iommu as a kernel module.

[1] https://lore.kernel.org/lkml/20200603161132.2441-1-miles.c...@mediatek.com/
[2] https://lore.kernel.org/lkml/20200604080120.2628-1-miles.c...@mediatek.com/
[3] https://lore.kernel.org/lkml/20200715205120.GA778876@bogus/

Cc: Mike Rapoport 
Cc: David Hildenbrand 
Cc: Yong Wu 
Cc: Yingjoe Chen 
Cc: Christoph Hellwig 
Cc: Rob Herring 
Cc: Matthias Brugger 
Signed-off-by: Miles Chen 

---

Change since v3
- use lore.kernel.org links
- move "change since..." after "---"

Change since v2:
- determine compatible string by m4u_plat
- rebase to next-20200720
- add "---"

Change since v1:
- remove the phandle usage, search for infracfg instead [3]
- use infracfg instead of infracfg_regmap
- move infracfg definitaions to linux/soc/mediatek/infracfg.h
- update enable_4GB only when has_4gb_mode
---
 drivers/iommu/mtk_iommu.c | 34 +++
 include/linux/soc/mediatek/infracfg.h |  3 +++
 2 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 785b228d39a6..adc350150492 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -3,7 +3,6 @@
  * Copyright (c) 2015-2016 MediaTek Inc.
  * Author: Yong Wu 
  */
-#include 
 #include 
 #include 
 #include 
@@ -15,13 +14,16 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
+#include 
 #include 
 #include 
 
@@ -640,8 +642,11 @@ static int mtk_iommu_probe(struct platform_device *pdev)
struct resource *res;
resource_size_t ioaddr;
struct component_match  *match = NULL;
+   struct regmap   *infracfg;
void*protect;
int i, larb_nr, ret;
+   u32 val;
+   char*p;
 
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
@@ -655,10 +660,29 @@ static int mtk_iommu_probe(struct platform_device *pdev)
return -ENOMEM;
data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN);
 
-   /* Whether the current dram is over 4GB */
-   data->enable_4GB = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT));
-   if (!MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE))
-   data->enable_4GB = false;
+   data->enable_4GB = false;
+   if (MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE)) {
+   switch (data->plat_data->m4u_plat) {
+   case M4U_MT2712:
+   p = "mediatek,mt2712-infracfg";
+   break;
+   case M4U_MT8173:
+   p = "mediatek,mt8173-infracfg";
+   break;
+   default:
+   p = NULL;
+   }
+
+   infracfg = syscon_regmap_lookup_by_compatible(p);
+
+   if (IS_ERR(infracfg))
+   return PTR_ERR(infracfg);
+
+   ret = regmap_read(infracfg, REG_INFRA_MISC, );
+   if (ret)
+   return ret;
+   data->enable_4GB = !!(val & F_DDR_4GB_SUPPORT_EN);
+   }
 
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
data->base = devm_ioremap_resource(dev, res);
diff --git a/include/linux/soc/mediatek/infracfg.h 
b/include/linux/soc/mediatek/infracfg.h
index fd25f0148566..233463d789c6 100644
--- a/include/linux/soc/mediatek/infracfg.h
+++ b/include/linux/soc/mediatek/infracfg.h
@@ -32,6 +32,9 @@
 #define MT7622_TOP_AXI_PROT_EN_WB  (BIT(2) | BIT(6) | \
 BIT(7) | BIT(8))
 
+#define REG_INFRA_MISC 0xf00
+#define F_DDR_4GB_SUPPORT_EN   BIT(13)
+
 int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask,
bool reg_update);
 int mtk_infracfg_clear_bus_protection(struct regmap *infracfg, u32 mask,
-- 
2.18.0
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[PATCH v4] iommu/mediatek: check 4GB mode by reading infracfg

2020-07-22 Thread Miles Chen 
In previous discussion [1] and [2], we found that it is risky to
use max_pfn or totalram_pages to tell if 4GB mode is enabled.

Check 4GB mode by reading infracfg register, remove the usage
of the un-exported symbol max_pfn.

This is a step towards building mtk_iommu as a kernel module.

[1] https://lore.kernel.org/lkml/20200603161132.2441-1-miles.c...@mediatek.com/
[2] https://lore.kernel.org/lkml/20200604080120.2628-1-miles.c...@mediatek.com/
[3] https://lore.kernel.org/lkml/20200715205120.GA778876@bogus/

Cc: Mike Rapoport 
Cc: David Hildenbrand 
Cc: Yong Wu 
Cc: Yingjoe Chen 
Cc: Christoph Hellwig 
Cc: Rob Herring 
Cc: Matthias Brugger 
Signed-off-by: Miles Chen 

---

Change since v3
- use lore.kernel.org links
- move "change since..." after "---"

Change since v2:
- determine compatible string by m4u_plat
- rebase to next-20200720
- add "---"

Change since v1:
- remove the phandle usage, search for infracfg instead [3]
- use infracfg instead of infracfg_regmap
- move infracfg definitaions to linux/soc/mediatek/infracfg.h
- update enable_4GB only when has_4gb_mode
---
 drivers/iommu/mtk_iommu.c | 34 +++
 include/linux/soc/mediatek/infracfg.h |  3 +++
 2 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 59e5a62a34db..9ec666168822 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -3,7 +3,6 @@
  * Copyright (c) 2015-2016 MediaTek Inc.
  * Author: Yong Wu 
  */
-#include 
 #include 
 #include 
 #include 
@@ -15,13 +14,16 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
+#include 
 #include 
 #include 
 
@@ -640,8 +642,11 @@ static int mtk_iommu_probe(struct platform_device *pdev)
struct resource *res;
resource_size_t ioaddr;
struct component_match  *match = NULL;
+   struct regmap   *infracfg;
void*protect;
int i, larb_nr, ret;
+   u32 val;
+   char*p;
 
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
@@ -655,10 +660,29 @@ static int mtk_iommu_probe(struct platform_device *pdev)
return -ENOMEM;
data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN);
 
-   /* Whether the current dram is over 4GB */
-   data->enable_4GB = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT));
-   if (!MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE))
-   data->enable_4GB = false;
+   data->enable_4GB = false;
+   if (MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE)) {
+   switch (data->plat_data->m4u_plat) {
+   case M4U_MT2712:
+   p = "mediatek,mt2712-infracfg";
+   break;
+   case M4U_MT8173:
+   p = "mediatek,mt8173-infracfg";
+   break;
+   default:
+   p = NULL;
+   }
+
+   infracfg = syscon_regmap_lookup_by_compatible(p);
+
+   if (IS_ERR(infracfg))
+   return PTR_ERR(infracfg);
+
+   ret = regmap_read(infracfg, REG_INFRA_MISC, );
+   if (ret)
+   return ret;
+   data->enable_4GB = !!(val & F_DDR_4GB_SUPPORT_EN);
+   }
 
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
data->base = devm_ioremap_resource(dev, res);
diff --git a/include/linux/soc/mediatek/infracfg.h 
b/include/linux/soc/mediatek/infracfg.h
index fd25f0148566..233463d789c6 100644
--- a/include/linux/soc/mediatek/infracfg.h
+++ b/include/linux/soc/mediatek/infracfg.h
@@ -32,6 +32,9 @@
 #define MT7622_TOP_AXI_PROT_EN_WB  (BIT(2) | BIT(6) | \
 BIT(7) | BIT(8))
 
+#define REG_INFRA_MISC 0xf00
+#define F_DDR_4GB_SUPPORT_EN   BIT(13)
+
 int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask,
bool reg_update);
 int mtk_infracfg_clear_bus_protection(struct regmap *infracfg, u32 mask,
-- 
2.18.0
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