Re: [PATCH/RFC] iommu/ipmmu-vmsa: IPMMU SYS-DMAC iova mapping workaround

[Niklas Söderlund]

Hi Magnus,

On 2016-09-27 15:43:30 +0900, Magnus Damm wrote:
> Hi Niklas,
> 
> On Tue, Sep 27, 2016 at 3:20 PM, Niklas Söderlund
>  wrote:
> > Hi Magnus,
> >
> > On 2016-09-20 20:54:33 +0900, Magnus Damm wrote:
> >> From: Magnus Damm 
> >>
> >> Here's some prototype code that works around the lack of software
> >> support for mapping I/O devices to the SYS-DMAC hardware via the
> >> DMA Engine framework when using IOMMU.
> >>
> >> The code itself is one big layering violation that goes through
> >> the DT and unconditionally maps I/O devices using DMACs via the
> >> IPMMU device instance into iova space with a 1:1 mapping.
> >>
> >> This very short term prototype will for instance automatically make
> >> the SCIF serial port function with the IPMMU hardware in case the
> >> SYS-DMAC is hooked up to the IPMMU device.
> >>
> >> Not to be confused with the more long term solution to allow the
> >> DMA Engine framework to map I/O device memory dynamically.
> >
> > Good news, Vinod queued the dma_{map,unmap}_resource API and rcar-dmac
> > usage of it yesterday \o/.
> 
> Excellent. Are the DMA Engine slave devices supposed to work out of
> the box with the IPMMU then, or is some other component missing?

The DT and shmobile_defconfig patches are missing. If you enable 
CONFIG_IPMMU_VMSA and wire up DT (see bellow for Koelsch example) then 
all devices I have tried works (MMC, I2C and serial consoles).

diff --git a/arch/arm/boot/dts/r8a7791.dtsi b/arch/arm/boot/dts/r8a7791.dtsi
index 8f0086b..d19bffd 100644
--- a/arch/arm/boot/dts/r8a7791.dtsi
+++ b/arch/arm/boot/dts/r8a7791.dtsi
@@ -325,6 +325,21 @@
power-domains = < R8A7791_PD_ALWAYS_ON>;
#dma-cells = <1>;
dma-channels = <15>;
+   iommus = <_ds 0>,
+<_ds 1>,
+<_ds 2>,
+<_ds 3>,
+<_ds 4>,
+<_ds 5>,
+<_ds 6>,
+<_ds 7>,
+<_ds 8>,
+<_ds 9>,
+<_ds 10>,
+<_ds 11>,
+<_ds 12>,
+<_ds 13>,
+<_ds 14>;
};
 
dmac1: dma-controller@e672 {
@@ -356,6 +371,21 @@
power-domains = < R8A7791_PD_ALWAYS_ON>;
#dma-cells = <1>;
dma-channels = <15>;
+   iommus = <_ds 15>,
+<_ds 16>,
+<_ds 17>,
+<_ds 18>,
+<_ds 19>,
+<_ds 20>,
+<_ds 21>,
+<_ds 22>,
+<_ds 23>,
+<_ds 24>,
+<_ds 25>,
+<_ds 26>,
+<_ds 27>,
+<_ds 28>,
+<_ds 29>;
};
 
audma0: dma-controller@ec70 {
@@ -1693,7 +1723,7 @@
interrupts = ,
 ;
#iommu-cells = <1>;
-   status = "disabled";
+   status = "okay";
};
 
ipmmu_mp: mmu@ec68 {

Also please note that I'm having problems with the next branch of 
git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/slave-dma.git and 
the commit 761ed4a (tty: serial_core: convert uart_close to use 
tty_port_close) together with a systemd init system. I have to revert to 
commit in order for the system to boot, but I will comment on that in a 
separate e-mail.

-- 
Regards,
Niklas Söderlund

Re: [PATCH/RFC] iommu/ipmmu-vmsa: IPMMU SYS-DMAC iova mapping workaround

[Magnus Damm]

Hi Niklas,

On Tue, Sep 27, 2016 at 3:20 PM, Niklas Söderlund
 wrote:
> Hi Magnus,
>
> On 2016-09-20 20:54:33 +0900, Magnus Damm wrote:
>> From: Magnus Damm 
>>
>> Here's some prototype code that works around the lack of software
>> support for mapping I/O devices to the SYS-DMAC hardware via the
>> DMA Engine framework when using IOMMU.
>>
>> The code itself is one big layering violation that goes through
>> the DT and unconditionally maps I/O devices using DMACs via the
>> IPMMU device instance into iova space with a 1:1 mapping.
>>
>> This very short term prototype will for instance automatically make
>> the SCIF serial port function with the IPMMU hardware in case the
>> SYS-DMAC is hooked up to the IPMMU device.
>>
>> Not to be confused with the more long term solution to allow the
>> DMA Engine framework to map I/O device memory dynamically.
>
> Good news, Vinod queued the dma_{map,unmap}_resource API and rcar-dmac
> usage of it yesterday \o/.

Excellent. Are the DMA Engine slave devices supposed to work out of
the box with the IPMMU then, or is some other component missing?

Cheers,

/ magnus

Re: [PATCH/RFC] iommu/ipmmu-vmsa: IPMMU SYS-DMAC iova mapping workaround

[Niklas Söderlund]

Hi Magnus,

On 2016-09-20 20:54:33 +0900, Magnus Damm wrote:
> From: Magnus Damm 
> 
> Here's some prototype code that works around the lack of software
> support for mapping I/O devices to the SYS-DMAC hardware via the
> DMA Engine framework when using IOMMU.
> 
> The code itself is one big layering violation that goes through
> the DT and unconditionally maps I/O devices using DMACs via the
> IPMMU device instance into iova space with a 1:1 mapping.
> 
> This very short term prototype will for instance automatically make
> the SCIF serial port function with the IPMMU hardware in case the
> SYS-DMAC is hooked up to the IPMMU device.
> 
> Not to be confused with the more long term solution to allow the
> DMA Engine framework to map I/O device memory dynamically.

Good news, Vinod queued the dma_{map,unmap}_resource API and rcar-dmac 
usage of it yesterday \o/.

> 
> Not-Yet-Signed-off-by: Magnus Damm 
> ---
> 
>  Applies on top of: renesas-drivers-2016-09-13-v4.8-rc6
> 
>  drivers/iommu/ipmmu-vmsa.c |   75 
> 
>  1 file changed, 75 insertions(+)
> 
> --- 0001/drivers/iommu/ipmmu-vmsa.c
> +++ work/drivers/iommu/ipmmu-vmsa.c   2016-09-20 20:03:37.620607110 +0900
> @@ -19,6 +19,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  #include 
>  #include 
>  #include 
> @@ -625,6 +626,78 @@ static void ipmmu_domain_free(struct iom
>   kfree(domain);
>  }
>  
> +static void ipmmu_workaround_map(struct iommu_domain *io_domain,
> +  struct device *dma_dev, struct resource *res)
> +{
> + phys_addr_t phys_addr;
> +
> + dev_info(dma_dev, "map %pr\n", res);
> +
> + phys_addr = iommu_iova_to_phys(io_domain, res->start);
> + if (phys_addr)
> + return;
> +
> + iommu_map(io_domain, res->start, res->start,
> +   ALIGN(resource_size(res), SZ_4K),
> +   IOMMU_READ | IOMMU_WRITE);
> +}
> +
> +static void ipmmu_workaround_dt(struct iommu_domain *io_domain,
> + struct device *dev,
> + void (*match)(struct iommu_domain *io_domain,
> +   struct device *dma_dev,
> +   struct resource *res))
> +{
> + struct device_node *np = NULL;
> + struct of_phandle_args dma_spec;
> + struct resource r;
> + int i, cnt;
> + bool found;
> +
> + /* Locate I/O devices using the DMAC and map their registers */
> + while ((np = of_find_all_nodes(np))) {
> + if (!of_find_property(np, "dmas", NULL))
> + continue;
> +
> + cnt = of_property_count_strings(np, "dma-names");
> + if (cnt < 0)
> + continue;
> +
> + found = false;
> + for (i = 0; i < cnt; i++) {
> + if (of_parse_phandle_with_args(np, "dmas",
> +"#dma-cells", i,
> +_spec))
> + continue;
> +
> + if (dma_spec.np == dev->of_node)
> + found = true;
> +
> + of_node_put(dma_spec.np);
> + }
> +
> + if (!found)
> + continue;
> +
> + i = 0;
> + while (!of_address_to_resource(np, i, )) {
> + match(io_domain, dev, );
> + i++;
> + }
> + }
> +}
> +
> +static void ipmmu_workaround(struct iommu_domain *io_domain,
> +  struct device *dev)
> +{
> + /* only apply workaround for DMA controllers */
> + if (!strstr(dev_name(dev), "dma-controller"))
> + return;
> +
> + dev_info(dev, "Adding iommu workaround to map I/O devices for DMACs\n");
> + ipmmu_workaround_dt(io_domain, dev, ipmmu_workaround_map);
> +}
> +
>  static int ipmmu_attach_device(struct iommu_domain *io_domain,
>  struct device *dev)
>  {
> @@ -678,6 +751,8 @@ static int ipmmu_attach_device(struct io
>   if (ret < 0)
>   return ret;
>  
> + ipmmu_workaround(io_domain, dev);
> +
>   for (i = 0; i < archdata->num_utlbs; ++i)
>   ipmmu_utlb_enable(domain, archdata->utlbs[i]);
>  

-- 
Regards,
Niklas Söderlund

[PATCH/RFC] iommu/ipmmu-vmsa: IPMMU SYS-DMAC iova mapping workaround

[Magnus Damm]

From: Magnus Damm 

Here's some prototype code that works around the lack of software
support for mapping I/O devices to the SYS-DMAC hardware via the
DMA Engine framework when using IOMMU.

The code itself is one big layering violation that goes through
the DT and unconditionally maps I/O devices using DMACs via the
IPMMU device instance into iova space with a 1:1 mapping.

This very short term prototype will for instance automatically make
the SCIF serial port function with the IPMMU hardware in case the
SYS-DMAC is hooked up to the IPMMU device.

Not to be confused with the more long term solution to allow the
DMA Engine framework to map I/O device memory dynamically.

Not-Yet-Signed-off-by: Magnus Damm 
---

 Applies on top of: renesas-drivers-2016-09-13-v4.8-rc6

 drivers/iommu/ipmmu-vmsa.c |   75 
 1 file changed, 75 insertions(+)

--- 0001/drivers/iommu/ipmmu-vmsa.c
+++ work/drivers/iommu/ipmmu-vmsa.c 2016-09-20 20:03:37.620607110 +0900
@@ -19,6 +19,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -625,6 +626,78 @@ static void ipmmu_domain_free(struct iom
kfree(domain);
 }
 
+static void ipmmu_workaround_map(struct iommu_domain *io_domain,
+struct device *dma_dev, struct resource *res)
+{
+   phys_addr_t phys_addr;
+
+   dev_info(dma_dev, "map %pr\n", res);
+
+   phys_addr = iommu_iova_to_phys(io_domain, res->start);
+   if (phys_addr)
+   return;
+
+   iommu_map(io_domain, res->start, res->start,
+ ALIGN(resource_size(res), SZ_4K),
+ IOMMU_READ | IOMMU_WRITE);
+}
+
+static void ipmmu_workaround_dt(struct iommu_domain *io_domain,
+   struct device *dev,
+   void (*match)(struct iommu_domain *io_domain,
+ struct device *dma_dev,
+ struct resource *res))
+{
+   struct device_node *np = NULL;
+   struct of_phandle_args dma_spec;
+   struct resource r;
+   int i, cnt;
+   bool found;
+
+   /* Locate I/O devices using the DMAC and map their registers */
+   while ((np = of_find_all_nodes(np))) {
+   if (!of_find_property(np, "dmas", NULL))
+   continue;
+
+   cnt = of_property_count_strings(np, "dma-names");
+   if (cnt < 0)
+   continue;
+
+   found = false;
+   for (i = 0; i < cnt; i++) {
+   if (of_parse_phandle_with_args(np, "dmas",
+  "#dma-cells", i,
+  _spec))
+   continue;
+
+   if (dma_spec.np == dev->of_node)
+   found = true;
+
+   of_node_put(dma_spec.np);
+   }
+
+   if (!found)
+   continue;
+
+   i = 0;
+   while (!of_address_to_resource(np, i, )) {
+   match(io_domain, dev, );
+   i++;
+   }
+   }
+}
+
+static void ipmmu_workaround(struct iommu_domain *io_domain,
+struct device *dev)
+{
+   /* only apply workaround for DMA controllers */
+   if (!strstr(dev_name(dev), "dma-controller"))
+   return;
+
+   dev_info(dev, "Adding iommu workaround to map I/O devices for DMACs\n");
+   ipmmu_workaround_dt(io_domain, dev, ipmmu_workaround_map);
+}
+
 static int ipmmu_attach_device(struct iommu_domain *io_domain,
   struct device *dev)
 {
@@ -678,6 +751,8 @@ static int ipmmu_attach_device(struct io
if (ret < 0)
return ret;
 
+   ipmmu_workaround(io_domain, dev);
+
for (i = 0; i < archdata->num_utlbs; ++i)
ipmmu_utlb_enable(domain, archdata->utlbs[i]);