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[PATCH v3 02/09] iommu/ipmmu-vmsa: Add optional root device feature

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  [PATCH v3 02/09] iommu/ipmmu-vmsa: Add optional root device feature Magnus Damm <magnus.damm@gmail.com> - 2017-03-08 12:10 +0100
    Re: [PATCH v3 02/09] iommu/ipmmu-vmsa: Add optional root device feature Geert Uytterhoeven <geert@linux-m68k.org> - 2017-03-08 15:00 +0100
      Re: [PATCH v3 02/09] iommu/ipmmu-vmsa: Add optional root device feature Magnus Damm <magnus.damm@gmail.com> - 2017-03-09 05:40 +0100

#1595053 — [PATCH v3 02/09] iommu/ipmmu-vmsa: Add optional root device feature

From: Magnus Damm <damm+renesas@opensource.se>

Add root device handling to the IPMMU driver by allowing certain
DT compat strings to enable has_cache_leaf_nodes that in turn will
support both root devices with interrupts and leaf devices that
face the actual IPMMU consumer devices.

Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
---

 Changes since V2:
 - Fixed a bug in ipmmu_find_root() when only leaf devices are present
 - Broke out __ipmmu_find_root() to allow ->xlate() check for root devices

 Changes since V1:
 - Moved patch to earlier in the series
 - Updated code to work with recent changes in:
   [PATCH v3 00/06] iommu/ipmmu-vmsa: IPMMU multi-arch update V3

 drivers/iommu/ipmmu-vmsa.c |   95 ++++++++++++++++++++++++++++++++++++--------
 1 file changed, 78 insertions(+), 17 deletions(-)

--- 0011/drivers/iommu/ipmmu-vmsa.c
+++ work/drivers/iommu/ipmmu-vmsa.c	2017-03-08 17:56:51.770607110 +0900
@@ -34,6 +34,7 @@
 
 struct ipmmu_features {
 	bool use_ns_alias_offset;
+	bool has_cache_leaf_nodes;
 };
 
 struct ipmmu_vmsa_device {
@@ -41,6 +42,7 @@ struct ipmmu_vmsa_device {
 	void __iomem *base;
 	struct list_head list;
 	const struct ipmmu_features *features;
+	bool is_leaf;
 	unsigned int num_utlbs;
 	spinlock_t lock;			/* Protects ctx and domains[] */
 	DECLARE_BITMAP(ctx, IPMMU_CTX_MAX);
@@ -51,6 +53,7 @@ struct ipmmu_vmsa_device {
 
 struct ipmmu_vmsa_domain {
 	struct ipmmu_vmsa_device *mmu;
+	struct ipmmu_vmsa_device *root;
 	struct iommu_domain io_domain;
 
 	struct io_pgtable_cfg cfg;
@@ -216,6 +219,44 @@ static void set_archdata(struct device *
 #define IMUASID_ASID0_SHIFT		0
 
 /* -----------------------------------------------------------------------------
+ * Root device handling
+ */
+
+static bool ipmmu_is_root(struct ipmmu_vmsa_device *mmu)
+{
+	if (mmu->features->has_cache_leaf_nodes)
+		return mmu->is_leaf ? false : true;
+	else
+		return true; /* older IPMMU hardware treated as single root */
+}
+
+static struct ipmmu_vmsa_device *__ipmmu_find_root(void)
+{
+	struct ipmmu_vmsa_device *mmu;
+	bool found = false;
+
+	spin_lock(&ipmmu_devices_lock);
+
+	list_for_each_entry(mmu, &ipmmu_devices, list) {
+		if (ipmmu_is_root(mmu)) {
+			found = true;
+			break;
+		}
+	}
+
+	spin_unlock(&ipmmu_devices_lock);
+	return found ? mmu : NULL;
+}
+
+static struct ipmmu_vmsa_device *ipmmu_find_root(struct ipmmu_vmsa_device *leaf)
+{
+	if (ipmmu_is_root(leaf))
+		return leaf;
+	else
+		return __ipmmu_find_root();
+}
+
+/* -----------------------------------------------------------------------------
  * Read/Write Access
  */
 
@@ -232,13 +273,13 @@ static void ipmmu_write(struct ipmmu_vms
 
 static u32 ipmmu_ctx_read(struct ipmmu_vmsa_domain *domain, unsigned int reg)
 {
-	return ipmmu_read(domain->mmu, domain->context_id * IM_CTX_SIZE + reg);
+	return ipmmu_read(domain->root, domain->context_id * IM_CTX_SIZE + reg);
 }
 
 static void ipmmu_ctx_write(struct ipmmu_vmsa_domain *domain, unsigned int reg,
 			    u32 data)
 {
-	ipmmu_write(domain->mmu, domain->context_id * IM_CTX_SIZE + reg, data);
+	ipmmu_write(domain->root, domain->context_id * IM_CTX_SIZE + reg, data);
 }
 
 /* -----------------------------------------------------------------------------
@@ -373,7 +414,7 @@ static int ipmmu_domain_init_context(str
 	 * TODO: Add support for coherent walk through CCI with DVM and remove
 	 * cache handling. For now, delegate it to the io-pgtable code.
 	 */
-	domain->cfg.iommu_dev = domain->mmu->dev;
+	domain->cfg.iommu_dev = domain->root->dev;
 
 	domain->iop = alloc_io_pgtable_ops(ARM_32_LPAE_S1, &domain->cfg,
 					   domain);
@@ -383,7 +424,7 @@ static int ipmmu_domain_init_context(str
 	/*
 	 * Find an unused context.
 	 */
-	ret = ipmmu_domain_allocate_context(domain->mmu, domain);
+	ret = ipmmu_domain_allocate_context(domain->root, domain);
 	if (ret == IPMMU_CTX_MAX) {
 		free_io_pgtable_ops(domain->iop);
 		return -EBUSY;
@@ -454,7 +495,7 @@ static void ipmmu_domain_destroy_context
 	 */
 	ipmmu_ctx_write(domain, IMCTR, IMCTR_FLUSH);
 	ipmmu_tlb_sync(domain);
-	ipmmu_domain_free_context(domain->mmu, domain->context_id);
+	ipmmu_domain_free_context(domain->root, domain->context_id);
 }
 
 /* -----------------------------------------------------------------------------
@@ -567,7 +608,7 @@ static int ipmmu_attach_device(struct io
 			       struct device *dev)
 {
 	struct ipmmu_vmsa_archdata *archdata = to_archdata(dev);
-	struct ipmmu_vmsa_device *mmu = archdata->mmu;
+	struct ipmmu_vmsa_device *root, *mmu = archdata->mmu;
 	struct ipmmu_vmsa_domain *domain = to_vmsa_domain(io_domain);
 	unsigned long flags;
 	unsigned int i;
@@ -578,11 +619,18 @@ static int ipmmu_attach_device(struct io
 		return -ENXIO;
 	}
 
+	root = ipmmu_find_root(archdata->mmu);
+	if (!root) {
+		dev_err(dev, "Unable to locate root IPMMU\n");
+		return -EAGAIN;
+	}
+
 	spin_lock_irqsave(&domain->lock, flags);
 
 	if (!domain->mmu) {
 		/* The domain hasn't been used yet, initialize it. */
 		domain->mmu = mmu;
+		domain->root = root;
 		ret = ipmmu_domain_init_context(domain);
 	} else if (domain->mmu != mmu) {
 		/*
@@ -1005,6 +1053,7 @@ static void ipmmu_device_reset(struct ip
 
 static const struct ipmmu_features ipmmu_features_default = {
 	.use_ns_alias_offset = true,
+	.has_cache_leaf_nodes = false,
 };
 
 static const struct of_device_id ipmmu_of_ids[] = {
@@ -1064,19 +1113,31 @@ static int ipmmu_probe(struct platform_d
 		mmu->base += IM_NS_ALIAS_OFFSET;
 
 	irq = platform_get_irq(pdev, 0);
-	if (irq < 0) {
-		dev_err(&pdev->dev, "no IRQ found\n");
-		return irq;
-	}
 
-	ret = devm_request_irq(&pdev->dev, irq, ipmmu_irq, 0,
-			       dev_name(&pdev->dev), mmu);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "failed to request IRQ %d\n", irq);
-		return ret;
-	}
+	/*
+	 * Determine if this IPMMU instance is a leaf device by checking
+	 * if the renesas,ipmmu-main property exists or not.
+	 */
+	if (mmu->features->has_cache_leaf_nodes &&
+	    of_find_property(pdev->dev.of_node, "renesas,ipmmu-main", NULL))
+		mmu->is_leaf = true;
+
+	/* Root devices have mandatory IRQs */
+	if (ipmmu_is_root(mmu)) {
+		if (irq < 0) {
+			dev_err(&pdev->dev, "no IRQ found\n");
+			return irq;
+		}
 
-	ipmmu_device_reset(mmu);
+		ret = devm_request_irq(&pdev->dev, irq, ipmmu_irq, 0,
+				       dev_name(&pdev->dev), mmu);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "failed to request IRQ %d\n", irq);
+			return ret;
+		}
+
+		ipmmu_device_reset(mmu);
+	}
 
 	/*
 	 * We can't create the ARM mapping here as it requires the bus to have

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#1595192

Hi Magnus,

On Wed, Mar 8, 2017 at 12:01 PM, Magnus Damm <magnus.damm@gmail.com> wrote:
> From: Magnus Damm <damm+renesas@opensource.se>
>
> Add root device handling to the IPMMU driver by allowing certain
> DT compat strings to enable has_cache_leaf_nodes that in turn will
> support both root devices with interrupts and leaf devices that
> face the actual IPMMU consumer devices.
>
> Signed-off-by: Magnus Damm <damm+renesas@opensource.se>

> --- 0011/drivers/iommu/ipmmu-vmsa.c
> +++ work/drivers/iommu/ipmmu-vmsa.c     2017-03-08 17:56:51.770607110 +0900

> @@ -216,6 +219,44 @@ static void set_archdata(struct device *
>  #define IMUASID_ASID0_SHIFT            0
>
>  /* -----------------------------------------------------------------------------
> + * Root device handling
> + */
> +
> +static bool ipmmu_is_root(struct ipmmu_vmsa_device *mmu)
> +{
> +       if (mmu->features->has_cache_leaf_nodes)
> +               return mmu->is_leaf ? false : true;

Expressions using the ternary operator are sometimes hard to read.
In this case, you want negation, so why not use that?

return !mmu->is_leaf;

> +       else

I'd drop the else.

> +               return true; /* older IPMMU hardware treated as single root */
> +}
> +
> +static struct ipmmu_vmsa_device *__ipmmu_find_root(void)
> +{
> +       struct ipmmu_vmsa_device *mmu;
> +       bool found = false;

struct ipmmu_vmsa_device *root = NULL;

> +
> +       spin_lock(&ipmmu_devices_lock);
> +
> +       list_for_each_entry(mmu, &ipmmu_devices, list) {
> +               if (ipmmu_is_root(mmu)) {
> +                       found = true;

root = mmu;

> +                       break;
> +               }
> +       }
> +
> +       spin_unlock(&ipmmu_devices_lock);
> +       return found ? mmu : NULL;

return root;

> +}

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

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#1595672

Hi Geert,

On Wed, Mar 8, 2017 at 10:47 PM, Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
> Hi Magnus,
>
> On Wed, Mar 8, 2017 at 12:01 PM, Magnus Damm <magnus.damm@gmail.com> wrote:
>> From: Magnus Damm <damm+renesas@opensource.se>
>>
>> Add root device handling to the IPMMU driver by allowing certain
>> DT compat strings to enable has_cache_leaf_nodes that in turn will
>> support both root devices with interrupts and leaf devices that
>> face the actual IPMMU consumer devices.
>>
>> Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
>
>> --- 0011/drivers/iommu/ipmmu-vmsa.c
>> +++ work/drivers/iommu/ipmmu-vmsa.c     2017-03-08 17:56:51.770607110 +0900
>
>> @@ -216,6 +219,44 @@ static void set_archdata(struct device *
>>  #define IMUASID_ASID0_SHIFT            0
>>
>>  /* -----------------------------------------------------------------------------
>> + * Root device handling
>> + */
>> +
>> +static bool ipmmu_is_root(struct ipmmu_vmsa_device *mmu)
>> +{
>> +       if (mmu->features->has_cache_leaf_nodes)
>> +               return mmu->is_leaf ? false : true;
>
> Expressions using the ternary operator are sometimes hard to read.
> In this case, you want negation, so why not use that?
>
> return !mmu->is_leaf;
>
>> +       else
>
> I'd drop the else.

Yeah, your suggestion makes the code easier to read. Will fix.

>> +               return true; /* older IPMMU hardware treated as single root */
>> +}
>> +
>> +static struct ipmmu_vmsa_device *__ipmmu_find_root(void)
>> +{
>> +       struct ipmmu_vmsa_device *mmu;
>> +       bool found = false;
>
> struct ipmmu_vmsa_device *root = NULL;

I used to have it initialized to NULL and not use any found variable
and only return the variable. But then I ran into the error case when
devices exist on the ipmmu_devices list however none of them are root.
I returned the last one on the list regardless if they were root or
not. So I updated the code to use the found variable, and because of
that I thought I could simply drop the NULL assignment.

>> +
>> +       spin_lock(&ipmmu_devices_lock);
>> +
>> +       list_for_each_entry(mmu, &ipmmu_devices, list) {
>> +               if (ipmmu_is_root(mmu)) {
>> +                       found = true;
>
> root = mmu;
>
>> +                       break;
>> +               }
>> +       }
>> +
>> +       spin_unlock(&ipmmu_devices_lock);
>> +       return found ? mmu : NULL;
>
> return root;

I agree it makes sense to use root as variable name, will fix. Not
sure about the NULL assignment though, can you enlighten me?

Cheers,

/ magnus

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