[PATCH v6 06/11] powerpc/pseries/iommu: Add ddw_property_create() and refactor enable_ddw()

Leonardo Bras
2021-08-17T06:40:40Z

Code used to create a ddw property that was previously scattered in
enable_ddw() is now gathered in ddw_property_create(), which deals with
allocation and filling the property, letting it ready for
of_property_add(), which now occurs in sequence.

This created an opportunity to reorganize the second part of enable_ddw():

Without this patch enable_ddw() does, in order:
kzalloc() property & members, create_ddw(), fill ddwprop inside property,
ddw_list_new_entry(), do tce_setrange_multi_pSeriesLP_walk in all memory,
of_add_property(), and list_add().

With this patch enable_ddw() does, in order:
create_ddw(), ddw_property_create(), of_add_property(),
ddw_list_new_entry(), do tce_setrange_multi_pSeriesLP_walk in all memory,
and list_add().

This change requires of_remove_property() in case anything fails after
of_add_property(), but we get to do tce_setrange_multi_pSeriesLP_walk
in all memory, which looks the most expensive operation, only if
everything else succeeds.

Also, the error path got remove_ddw() replaced by a new helper
__remove_dma_window(), which only removes the new DDW with an rtas-call.
For this, a new helper clean_dma_window() was needed to clean anything
that could left if walk_system_ram_range() fails.

Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
arch/powerpc/platforms/pseries/iommu.c | 129 ++++++++++++++++---------
1 file changed, 84 insertions(+), 45 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index b34b473bbdc1..00392582fe10 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -795,17 +795,10 @@ static int __init disable_ddw_setup(char *str)

early_param("disable_ddw", disable_ddw_setup);

-static void remove_dma_window(struct device_node *np, u32 *ddw_avail,
- struct property *win)
+static void clean_dma_window(struct device_node *np, struct dynamic_dma_window_prop *dwp)
{
- struct dynamic_dma_window_prop *dwp;
- u64 liobn;
int ret;

- dwp = win->value;
- liobn = (u64)be32_to_cpu(dwp->liobn);
-
- /* clear the whole window, note the arg is in kernel pages */
ret = tce_clearrange_multi_pSeriesLP(0,
1ULL << (be32_to_cpu(dwp->window_shift) - PAGE_SHIFT), dwp);
if (ret)
@@ -814,18 +807,39 @@ static void remove_dma_window(struct device_node *np, u32 *ddw_avail,
else
pr_debug("%pOF successfully cleared tces in window.\n",
np);
+}
+
+/*
+ * Call only if DMA window is clean.
+ */
+static void __remove_dma_window(struct device_node *np, u32 *ddw_avail, u64 liobn)
+{
+ int ret;

ret = rtas_call(ddw_avail[DDW_REMOVE_PE_DMA_WIN], 1, 1, NULL, liobn);
if (ret)
- pr_warn("%pOF: failed to remove direct window: rtas returned "
+ pr_warn("%pOF: failed to remove DMA window: rtas returned "
"%d to ibm,remove-pe-dma-window(%x) %llx\n",
np, ret, ddw_avail[DDW_REMOVE_PE_DMA_WIN], liobn);
else
- pr_debug("%pOF: successfully removed direct window: rtas returned "
+ pr_debug("%pOF: successfully removed DMA window: rtas returned "
"%d to ibm,remove-pe-dma-window(%x) %llx\n",
np, ret, ddw_avail[DDW_REMOVE_PE_DMA_WIN], liobn);
}

+static void remove_dma_window(struct device_node *np, u32 *ddw_avail,
+ struct property *win)
+{
+ struct dynamic_dma_window_prop *dwp;
+ u64 liobn;
+
+ dwp = win->value;
+ liobn = (u64)be32_to_cpu(dwp->liobn);
+
+ clean_dma_window(np, dwp);
+ __remove_dma_window(np, ddw_avail, liobn);
+}
+
static void remove_ddw(struct device_node *np, bool remove_prop)
{
struct property *win;
@@ -1153,6 +1167,35 @@ static int iommu_get_page_shift(u32 query_page_size)
return 0;
}

+static struct property *ddw_property_create(const char *propname, u32 liobn, u64 dma_addr,
+ u32 page_shift, u32 window_shift)
+{
+ struct dynamic_dma_window_prop *ddwprop;
+ struct property *win64;
+
+ win64 = kzalloc(sizeof(*win64), GFP_KERNEL);
+ if (!win64)
+ return NULL;
+
+ win64->name = kstrdup(propname, GFP_KERNEL);
+ ddwprop = kzalloc(sizeof(*ddwprop), GFP_KERNEL);
+ win64->value = ddwprop;
+ win64->length = sizeof(*ddwprop);
+ if (!win64->name || !win64->value) {
+ kfree(win64->name);
+ kfree(win64->value);
+ kfree(win64);
+ return NULL;
+ }
+
+ ddwprop->liobn = cpu_to_be32(liobn);
+ ddwprop->dma_base = cpu_to_be64(dma_addr);
+ ddwprop->tce_shift = cpu_to_be32(page_shift);
+ ddwprop->window_shift = cpu_to_be32(window_shift);
+
+ return win64;
+}
+
/*
* If the PE supports dynamic dma windows, and there is space for a table
* that can map all pages in a linear offset, then setup such a table,
@@ -1171,12 +1214,12 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
struct ddw_query_response query;
struct ddw_create_response create;
int page_shift;
+ u64 win_addr;
struct device_node *dn;
u32 ddw_avail[DDW_APPLICABLE_SIZE];
struct direct_window *window;
struct property *win64;
bool ddw_enabled = false;
- struct dynamic_dma_window_prop *ddwprop;
struct failed_ddw_pdn *fpdn;
bool default_win_removed = false;
bool pmem_present;
@@ -1293,72 +1336,68 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
1ULL << page_shift);
goto out_failed;
}
- win64 = kzalloc(sizeof(struct property), GFP_KERNEL);
- if (!win64) {
- dev_info(&dev->dev,
- "couldn't allocate property for 64bit dma window\n");
- goto out_failed;
- }
- win64->name = kstrdup(DIRECT64_PROPNAME, GFP_KERNEL);
- win64->value = ddwprop = kmalloc(sizeof(*ddwprop), GFP_KERNEL);
- win64->length = sizeof(*ddwprop);
- if (!win64->name || !win64->value) {
- dev_info(&dev->dev,
- "couldn't allocate property name and value\n");
- goto out_free_prop;
- }

ret = create_ddw(dev, ddw_avail, &create, page_shift, len);
if (ret != 0)
- goto out_free_prop;
-
- ddwprop->liobn = cpu_to_be32(create.liobn);
- ddwprop->dma_base = cpu_to_be64(((u64)create.addr_hi << 32) |
- create.addr_lo);
- ddwprop->tce_shift = cpu_to_be32(page_shift);
- ddwprop->window_shift = cpu_to_be32(len);
+ goto out_failed;

dev_dbg(&dev->dev, "created tce table LIOBN 0x%x for %pOF\n",
create.liobn, dn);

- window = ddw_list_new_entry(pdn, ddwprop);
+ win_addr = ((u64)create.addr_hi << 32) | create.addr_lo;
+ win64 = ddw_property_create(DIRECT64_PROPNAME, create.liobn, win_addr,
+ page_shift, len);
+ if (!win64) {
+ dev_info(&dev->dev,
+ "couldn't allocate property, property name, or value\n");
+ goto out_remove_win;
+ }
+
+ ret = of_add_property(pdn, win64);
+ if (ret) {
+ dev_err(&dev->dev, "unable to add dma window property for %pOF: %d",
+ pdn, ret);
+ goto out_free_prop;
+ }
+
+ window = ddw_list_new_entry(pdn, win64->value);
if (!window)
- goto out_clear_window;
+ goto out_del_prop;

ret = walk_system_ram_range(0, memblock_end_of_DRAM() >> PAGE_SHIFT,
win64->value, tce_setrange_multi_pSeriesLP_walk);
if (ret) {
dev_info(&dev->dev, "failed to map direct window for %pOF: %d\n",
dn, ret);
- goto out_free_window;
- }

- ret = of_add_property(pdn, win64);
- if (ret) {
- dev_err(&dev->dev, "unable to add dma window property for %pOF: %d",
- pdn, ret);
- goto out_free_window;
+ /* Make sure to clean DDW if any TCE was set*/
+ clean_dma_window(pdn, win64->value);
+ goto out_del_list;
}

spin_lock(&direct_window_list_lock);
list_add(&window->list, &direct_window_list);
spin_unlock(&direct_window_list_lock);

- dev->dev.archdata.dma_offset = be64_to_cpu(ddwprop->dma_base);
+ dev->dev.archdata.dma_offset = win_addr;
ddw_enabled = true;
goto out_unlock;

-out_free_window:
+out_del_list:
kfree(window);

-out_clear_window:
- remove_ddw(pdn, true);
+out_del_prop:
+ of_remove_property(pdn, win64);

out_free_prop:
kfree(win64->name);
kfree(win64->value);
kfree(win64);

+out_remove_win:
+ /* DDW is clean, so it's ok to call this directly. */
+ __remove_dma_window(pdn, ddw_avail, create.liobn);
+
out_failed:
if (default_win_removed)
reset_dma_window(dev, pdn);
--
2.32.0