Re: [RFC PATCH 7/7 v2] ppc: add dynamic dma window support
On 26.10.2010 [20:35:17 -0700], Nishanth Aravamudan wrote:
> If firmware allows us to map all of a partition's memory for DMA on a
> particular bridge, create a 1:1 mapping of that memory. Add hooks for
> dealing with hotplug events. Dyanmic DMA windows can use larger than the
> default page size, and we use the largest one possible.
>
> Not-yet-signed-off-by: Nishanth Aravamudan
>
> ---
>
> I've tested this briefly on a machine with suitable firmware/hardware.
> Things seem to work well, but I want to do more exhaustive I/O testing
> before asking for upstream merging. I would really appreciate any
> feedback on the updated approach.
>
> Specific questions:
>
> Ben, did I hook into the dma_set_mask() platform callback as you
> expected? Anything I can do better or which perhaps might lead to
> gotchas later?
>
> I've added a disable_ddw option, but perhaps it would be better to
> just disable the feature if iommu=force?
So for the final version, I probably should document this option in
kernel-parameters.txt w/ the patch, right?
> +static int tce_clearrange_multi_pSeriesLP(unsigned long start_pfn,
> + unsigned long num_pfn, const void *arg)
> +{
> + const struct dynamic_dma_window_prop *maprange = arg;
> + int rc;
> + u64 tce_size, num_tce, dma_offset, next;
> + u32 tce_shift;
> + long limit;
> +
> + tce_shift = be32_to_cpu(maprange->tce_shift);
> + tce_size = 1ULL << tce_shift;
> + next = start_pfn << PAGE_SHIFT;
> + num_tce = num_pfn << PAGE_SHIFT;
> +
> + /* round back to the beginning of the tce page size */
> + num_tce += next & (tce_size - 1);
> + next &= ~(tce_size - 1);
> +
> + /* covert to number of tces */
> + num_tce |= tce_size - 1;
> + num_tce >>= tce_shift;
> +
> + do {
> + /*
> + * Set up the page with TCE data, looping through and setting
> + * the values.
> + */
> + limit = min_t(long, num_tce, 512);
> + dma_offset = next + be64_to_cpu(maprange->dma_base);
> +
> + rc = plpar_tce_stuff(be64_to_cpu(maprange->liobn),
> + (u64)dma_offset,
> + 0, limit);
> + num_tce -= limit;
> + } while (num_tce > 0 && !rc);
> +
> + return rc;
> +}
There is a bit of a typo here, the liobn is a 32-bit value. I've fixed
this is up locally and will update it when I send out the final version
of this patch.
I'm finding that on dlpar remove of adapters running in slots supporting
64-bit DMA, that the plpar_tce_stuff is failing. Can you think of a
reason why? It looks basically the same as the put_indirect below...
> +static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
> + unsigned long num_pfn, const void *arg)
> +{
> + const struct dynamic_dma_window_prop *maprange = arg;
> + u64 *tcep, tce_size, num_tce, dma_offset, next, proto_tce, liobn;
> + u32 tce_shift;
> + u64 rc = 0;
> + long l, limit;
> +
> + local_irq_disable();/* to protect tcep and the page behind it */
> + tcep = __get_cpu_var(tce_page);
> +
> + if (!tcep) {
> + tcep = (u64 *)__get_free_page(GFP_ATOMIC);
> + if (!tcep) {
> + local_irq_enable();
> + return -ENOMEM;
> + }
> + __get_cpu_var(tce_page) = tcep;
> + }
> +
> + proto_tce = TCE_PCI_READ | TCE_PCI_WRITE;
> +
> + liobn = (u64)be32_to_cpu(maprange->liobn);
> + tce_shift = be32_to_cpu(maprange->tce_shift);
> + tce_size = 1ULL << tce_shift;
> + next = start_pfn << PAGE_SHIFT;
> + num_tce = num_pfn << PAGE_SHIFT;
> +
> + /* round back to the beginning of the tce page size */
> + num_tce += next & (tce_size - 1);
> + next &= ~(tce_size - 1);
> +
> + /* covert to number of tces */
> + num_tce |= tce_size - 1;
> + num_tce >>= tce_shift;
> +
> + /* We can map max one pageful of TCEs at a time */
> + do {
> + /*
> + * Set up the page with TCE data, looping through and setting
> + * the values.
> + */
> + limit = min_t(long, num_tce, 4096/TCE_ENTRY_SIZE);
> + dma_offset = next + be64_to_cpu(maprange->dma_base);
> +
> + for (l = 0; l < limit; l++) {
> + tcep[l] = proto_tce | next;
> + next += tce_size;
> + }
> +
> + rc = plpar_tce_put_indirect(liobn,
> + (u64)dma_offset,
> + (u64)virt_to_abs(tcep),
> + limit);
> +
> + num_tce -= limit;
> + } while (num_tce > 0 && !rc);
> +printk("plpar_tce_put_indirect for offset 0x%llx and tcep[0]
> 0x%llx returned %llu\n",
> +
Re: [RFC PATCH 7/7 v2] ppc: add dynamic dma window support
On 09.12.2010 [15:17:06 +1100], Benjamin Herrenschmidt wrote:
> On Tue, 2010-10-26 at 20:35 -0700, Nishanth Aravamudan wrote:
>
> No much comments... I'm amazed how complex he firmware folks managed to
> make this ...
>
> > static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned
> > long action, void *node)
> > {
> > int err = NOTIFY_OK;
> > struct device_node *np = node;
> > struct pci_dn *pci = PCI_DN(np);
> > + struct direct_window *window;
> >
> > switch (action) {
> > case PSERIES_RECONFIG_REMOVE:
> > if (pci && pci->iommu_table)
> > iommu_free_table(pci->iommu_table, np->full_name);
> > +
> > + spin_lock(&direct_window_list_lock);
> > + list_for_each_entry(window, &direct_window_list, list) {
> > + if (window->device == np) {
> > + list_del(&window->list);
> > + break;
> > + }
> > + }
> > + spin_unlock(&direct_window_list_lock);
>
> Should you also kfree the window ?
Yeah, looks like I should. I have a few other questions due to testing,
but I'll reply to my original e-mail with those.
Thanks for the review!
Nish
--
Nishanth Aravamudan
IBM Linux Technology Center
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Re: [RFC PATCH 7/7 v2] ppc: add dynamic dma window support
On Tue, 2010-10-26 at 20:35 -0700, Nishanth Aravamudan wrote:
No much comments... I'm amazed how complex he firmware folks managed to
make this ...
> static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long
> action, void *node)
> {
> int err = NOTIFY_OK;
> struct device_node *np = node;
> struct pci_dn *pci = PCI_DN(np);
> + struct direct_window *window;
>
> switch (action) {
> case PSERIES_RECONFIG_REMOVE:
> if (pci && pci->iommu_table)
> iommu_free_table(pci->iommu_table, np->full_name);
> +
> + spin_lock(&direct_window_list_lock);
> + list_for_each_entry(window, &direct_window_list, list) {
> + if (window->device == np) {
> + list_del(&window->list);
> + break;
> + }
> + }
> + spin_unlock(&direct_window_list_lock);
Should you also kfree the window ?
Cheers,
Ben.
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[RFC PATCH 7/7 v2] ppc: add dynamic dma window support
If firmware allows us to map all of a partition's memory for DMA on a
particular bridge, create a 1:1 mapping of that memory. Add hooks for
dealing with hotplug events. Dyanmic DMA windows can use larger than the
default page size, and we use the largest one possible.
Not-yet-signed-off-by: Nishanth Aravamudan
---
I've tested this briefly on a machine with suitable firmware/hardware.
Things seem to work well, but I want to do more exhaustive I/O testing
before asking for upstream merging. I would really appreciate any
feedback on the updated approach.
Specific questions:
Ben, did I hook into the dma_set_mask() platform callback as you
expected? Anything I can do better or which perhaps might lead to
gotchas later?
I've added a disable_ddw option, but perhaps it would be better to
just disable the feature if iommu=force?
---
arch/powerpc/platforms/pseries/iommu.c | 577 +++-
1 files changed, 575 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/iommu.c
b/arch/powerpc/platforms/pseries/iommu.c
index 45c6865..8090b6b 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -33,6 +33,7 @@
#include
#include
#include
+#include
#include
#include
#include
@@ -45,6 +46,7 @@
#include
#include
#include
+#include
#include "plpar_wrappers.h"
@@ -270,6 +272,139 @@ static unsigned long tce_get_pSeriesLP(struct iommu_table
*tbl, long tcenum)
return tce_ret;
}
+/* this is compatable with cells for the device tree property */
+struct dynamic_dma_window_prop {
+ __be32 liobn; /* tce table number */
+ __be64 dma_base; /* address hi,lo */
+ __be32 tce_shift; /* ilog2(tce_page_size) */
+ __be32 window_shift; /* ilog2(tce_window_size) */
+};
+
+struct direct_window {
+ struct device_node *device;
+ const struct dynamic_dma_window_prop *prop;
+ struct list_head list;
+};
+static LIST_HEAD(direct_window_list);
+/* prevents races between memory on/offline and window creation */
+static DEFINE_SPINLOCK(direct_window_list_lock);
+/* protects initializing window twice for same device */
+static DEFINE_MUTEX(direct_window_init_mutex);
+#define DIRECT64_PROPNAME "linux,direct64-ddr-window-info"
+
+static int tce_clearrange_multi_pSeriesLP(unsigned long start_pfn,
+ unsigned long num_pfn, const void *arg)
+{
+ const struct dynamic_dma_window_prop *maprange = arg;
+ int rc;
+ u64 tce_size, num_tce, dma_offset, next;
+ u32 tce_shift;
+ long limit;
+
+ tce_shift = be32_to_cpu(maprange->tce_shift);
+ tce_size = 1ULL << tce_shift;
+ next = start_pfn << PAGE_SHIFT;
+ num_tce = num_pfn << PAGE_SHIFT;
+
+ /* round back to the beginning of the tce page size */
+ num_tce += next & (tce_size - 1);
+ next &= ~(tce_size - 1);
+
+ /* covert to number of tces */
+ num_tce |= tce_size - 1;
+ num_tce >>= tce_shift;
+
+ do {
+ /*
+* Set up the page with TCE data, looping through and setting
+* the values.
+*/
+ limit = min_t(long, num_tce, 512);
+ dma_offset = next + be64_to_cpu(maprange->dma_base);
+
+ rc = plpar_tce_stuff(be64_to_cpu(maprange->liobn),
+ (u64)dma_offset,
+0, limit);
+ num_tce -= limit;
+ } while (num_tce > 0 && !rc);
+
+ return rc;
+}
+
+static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
+ unsigned long num_pfn, const void *arg)
+{
+ const struct dynamic_dma_window_prop *maprange = arg;
+ u64 *tcep, tce_size, num_tce, dma_offset, next, proto_tce, liobn;
+ u32 tce_shift;
+ u64 rc = 0;
+ long l, limit;
+
+ local_irq_disable();/* to protect tcep and the page behind it */
+ tcep = __get_cpu_var(tce_page);
+
+ if (!tcep) {
+ tcep = (u64 *)__get_free_page(GFP_ATOMIC);
+ if (!tcep) {
+ local_irq_enable();
+ return -ENOMEM;
+ }
+ __get_cpu_var(tce_page) = tcep;
+ }
+
+ proto_tce = TCE_PCI_READ | TCE_PCI_WRITE;
+
+ liobn = (u64)be32_to_cpu(maprange->liobn);
+ tce_shift = be32_to_cpu(maprange->tce_shift);
+ tce_size = 1ULL << tce_shift;
+ next = start_pfn << PAGE_SHIFT;
+ num_tce = num_pfn << PAGE_SHIFT;
+
+ /* round back to the beginning of the tce page size */
+ num_tce += next & (tce_size - 1);
+ next &= ~(tce_size - 1);
+
+ /* covert to number of tces */
+ num_tce |= tce_size - 1;
+ num_tce >>= tce_shift;
+
+ /* We can map max one pageful of TCEs at a time */
+ do {
+ /*
+*
