On 08/03/17 11:01, Magnus Damm wrote:
> From: Magnus Damm <damm+rene...@opensource.se>
>
> Add support for up to 8 contexts. Each context is mapped to one
> domain. One domain is assigned one or more slave devices. Contexts
> are allocated dynamically and slave devices are grouped together
> based on which IPMMU device they are connected to. This makes slave
> devices tied to the same IPMMU device share the same IOVA space.
>
> Signed-off-by: Magnus Damm <damm+rene...@opensource.se>
> ---
>
> Changes since V2:
> - Updated patch description to reflect code included in:
> [PATCH v7 00/07] iommu/ipmmu-vmsa: IPMMU multi-arch update V7
>
> Changes since V1:
> - Support up to 8 contexts instead of 4
> - Use feature flag and runtime handling
> - Default to single context
>
> drivers/iommu/ipmmu-vmsa.c | 38 ++++++++++++++++++++++++++++++--------
> 1 file changed, 30 insertions(+), 8 deletions(-)
>
> --- 0012/drivers/iommu/ipmmu-vmsa.c
> +++ work/drivers/iommu/ipmmu-vmsa.c 2017-03-08 17:59:19.900607110 +0900
> @@ -30,11 +30,12 @@
>
> #include "io-pgtable.h"
>
> -#define IPMMU_CTX_MAX 1
> +#define IPMMU_CTX_MAX 8
>
> struct ipmmu_features {
> bool use_ns_alias_offset;
> bool has_cache_leaf_nodes;
> + bool has_eight_ctx;
Wouldn't it be more sensible to just encode a number of contexts
directly, if it isn't reported by the hardware itself? I'm just
imagining future hardware generations... :P
bool also_has_another_eight_ctx_on_top_of_that;
bool wait_no_this_is_the_one_where_ctx_15_isnt_usable;
> };
>
> struct ipmmu_vmsa_device {
> @@ -44,6 +45,7 @@ struct ipmmu_vmsa_device {
> const struct ipmmu_features *features;
> bool is_leaf;
> unsigned int num_utlbs;
> + unsigned int num_ctx;
> spinlock_t lock; /* Protects ctx and domains[] */
> DECLARE_BITMAP(ctx, IPMMU_CTX_MAX);
> struct ipmmu_vmsa_domain *domains[IPMMU_CTX_MAX];
> @@ -376,11 +378,12 @@ static int ipmmu_domain_allocate_context
>
> spin_lock_irqsave(&mmu->lock, flags);
>
> - ret = find_first_zero_bit(mmu->ctx, IPMMU_CTX_MAX);
> - if (ret != IPMMU_CTX_MAX) {
> + ret = find_first_zero_bit(mmu->ctx, mmu->num_ctx);
> + if (ret != mmu->num_ctx) {
> mmu->domains[ret] = domain;
> set_bit(ret, mmu->ctx);
Using test_and_set_bit() in a loop would avoid having to take a lock here.
> - }
> + } else
> + ret = -EBUSY;
>
> spin_unlock_irqrestore(&mmu->lock, flags);
>
> @@ -425,9 +428,9 @@ static int ipmmu_domain_init_context(str
> * Find an unused context.
> */
> ret = ipmmu_domain_allocate_context(domain->root, domain);
> - if (ret == IPMMU_CTX_MAX) {
> + if (ret < 0) {
> free_io_pgtable_ops(domain->iop);
> - return -EBUSY;
> + return ret;
> }
>
> domain->context_id = ret;
> @@ -562,7 +565,7 @@ static irqreturn_t ipmmu_irq(int irq, vo
> /*
> * Check interrupts for all active contexts.
> */
> - for (i = 0; i < IPMMU_CTX_MAX; i++) {
> + for (i = 0; i < mmu->num_ctx; i++) {
> if (!mmu->domains[i])
> continue;
> if (ipmmu_domain_irq(mmu->domains[i]) == IRQ_HANDLED)
> @@ -632,6 +635,13 @@ static int ipmmu_attach_device(struct io
> domain->mmu = mmu;
> domain->root = root;
> ret = ipmmu_domain_init_context(domain);
> + if (ret < 0) {
> + dev_err(dev, "Unable to initialize IPMMU context\n");
> + domain->mmu = NULL;
> + } else {
> + dev_info(dev, "Using IPMMU context %u\n",
> + domain->context_id);
> + }
> } else if (domain->mmu != mmu) {
> /*
> * Something is wrong, we can't attach two devices using
> @@ -1047,13 +1057,14 @@ static void ipmmu_device_reset(struct ip
> unsigned int i;
>
> /* Disable all contexts. */
> - for (i = 0; i < 4; ++i)
> + for (i = 0; i < mmu->num_ctx; ++i)
> ipmmu_write(mmu, i * IM_CTX_SIZE + IMCTR, 0);
> }
>
> static const struct ipmmu_features ipmmu_features_default = {
> .use_ns_alias_offset = true,
> .has_cache_leaf_nodes = false,
> + .has_eight_ctx = false,
> };
>
> static const struct of_device_id ipmmu_of_ids[] = {
> @@ -1112,6 +1123,17 @@ static int ipmmu_probe(struct platform_d
> if (mmu->features->use_ns_alias_offset)
> mmu->base += IM_NS_ALIAS_OFFSET;
>
> + /*
> + * The number of contexts varies with generation and instance.
> + * Newer SoCs get a total of 8 contexts enabled, older ones just one.
> + */
> + if (mmu->features->has_eight_ctx)
> + mmu->num_ctx = 8;
> + else
> + mmu->num_ctx = 1;
> +
> + WARN_ON(mmu->num_ctx > IPMMU_CTX_MAX);
The likelihood of that happening doesn't appear to warrant a runtime
check. Especially one which probably isn't even generated because it's
trivially resolvable to "if (false)..." at compile time.
Robin.
> +
> irq = platform_get_irq(pdev, 0);
>
> /*
>
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