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Subject[PATCH V2 1/2] irqchip/gicv3-its: split its_alloc_tables() into two functions
Date
The function is getting out of control, it has too many goto
statements and would be too complicated for adding a feature
two-level device table. So, it is time for us to cleanup and
move some of the logic to a separate function without affecting
the existing functionality.

Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
---

This patch is based on Marc Zyngier's branch https://git.kernel.org/cgit/linux/kernel/git/maz/arm-platforms.git/log/?h=irq/irqchip-4.7

drivers/irqchip/irq-gic-v3-its.c | 256 ++++++++++++++++++++-----------------
include/linux/irqchip/arm-gic-v3.h | 3 +
2 files changed, 144 insertions(+), 115 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 6bd881b..b23e00c 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -55,13 +55,15 @@ struct its_collection {
};

/*
- * The ITS_BASER structure - contains memory information and cached
- * value of BASER register configuration.
+ * The ITS_BASER structure - contains memory information, cached value
+ * of BASER register configuration, ioremaped address and page size.
*/
struct its_baser {
+ void __iomem *hwreg;
void *base;
u64 val;
u32 order;
+ u32 psz;
};

/*
@@ -823,27 +825,135 @@ static void its_free_tables(struct its_node *its)
}
}

+static int its_baser_setup(struct its_node *its, struct its_baser *baser,
+ u32 order, u64 indirect)
+{
+ u64 val = readq_relaxed(baser->hwreg);
+ u64 type = GITS_BASER_TYPE(val);
+ u64 entry_size = GITS_BASER_ENTRY_SIZE(val);
+ int psz, alloc_pages;
+ u64 cache, shr, tmp;
+ void *base;
+
+ /* Do first attempt with the requested attributes */
+ cache = baser->val & GITS_BASER_CACHEABILITY_MASK;
+ shr = baser->val & GITS_BASER_SHAREABILITY_MASK;
+ psz = baser->psz;
+
+retry_alloc_baser:
+ alloc_pages = (PAGE_ORDER_TO_SIZE(order) / psz);
+ if (alloc_pages > GITS_BASER_PAGES_MAX) {
+ pr_warn("ITS@%lx: %s too large, reduce ITS pages %u->%u\n",
+ its->phys_base, its_base_type_string[type],
+ alloc_pages, GITS_BASER_PAGES_MAX);
+ alloc_pages = GITS_BASER_PAGES_MAX;
+ order = get_order(GITS_BASER_PAGES_MAX * psz);
+ }
+
+ base = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
+ if (!base)
+ return -ENOMEM;
+
+retry_baser:
+ val = (virt_to_phys(base) |
+ (type << GITS_BASER_TYPE_SHIFT) |
+ ((entry_size - 1) << GITS_BASER_ENTRY_SIZE_SHIFT) |
+ ((alloc_pages - 1) << GITS_BASER_PAGES_SHIFT) |
+ cache |
+ shr |
+ indirect |
+ GITS_BASER_VALID);
+
+ switch (psz) {
+ case SZ_4K:
+ val |= GITS_BASER_PAGE_SIZE_4K;
+ break;
+ case SZ_16K:
+ val |= GITS_BASER_PAGE_SIZE_16K;
+ break;
+ case SZ_64K:
+ val |= GITS_BASER_PAGE_SIZE_64K;
+ break;
+ }
+
+ writeq_relaxed(val, baser->hwreg);
+ tmp = readq_relaxed(baser->hwreg);
+
+ if ((val ^ tmp) & GITS_BASER_SHAREABILITY_MASK) {
+ /*
+ * Shareability didn't stick. Just use
+ * whatever the read reported, which is likely
+ * to be the only thing this redistributor
+ * supports. If that's zero, make it
+ * non-cacheable as well.
+ */
+ shr = tmp & GITS_BASER_SHAREABILITY_MASK;
+ if (!shr) {
+ cache = GITS_BASER_nC;
+ __flush_dcache_area(base, PAGE_ORDER_TO_SIZE(order));
+ }
+ goto retry_baser;
+ }
+
+ if ((val ^ tmp) & GITS_BASER_PAGE_SIZE_MASK) {
+ /*
+ * Page size didn't stick. Let's try a smaller
+ * size and retry. If we reach 4K, then
+ * something is horribly wrong...
+ */
+ free_pages((unsigned long)base, order);
+ baser->base = NULL;
+
+ switch (psz) {
+ case SZ_16K:
+ psz = SZ_4K;
+ goto retry_alloc_baser;
+ case SZ_64K:
+ psz = SZ_16K;
+ goto retry_alloc_baser;
+ }
+ }
+
+ if (val != tmp) {
+ pr_err("ITS@%lx: %s doesn't stick: %lx %lx\n",
+ its->phys_base, its_base_type_string[type],
+ (unsigned long) val, (unsigned long) tmp);
+ free_pages((unsigned long)base, order);
+ return -ENXIO;
+ }
+
+ baser->base = base;
+ baser->order = order;
+ baser->psz = psz;
+ baser->val = val;
+ tmp = indirect ? GITS_LVL1_ENTRY_SIZE : entry_size;
+
+ pr_info("ITS@%lx: allocated %d %s @%lx (%s, esz %d, psz %dK, shr %d)\n",
+ its->phys_base, (int)(PAGE_ORDER_TO_SIZE(order) / tmp),
+ its_base_type_string[type],
+ (unsigned long)virt_to_phys(base),
+ indirect ? "indirect" : "flat", (int)entry_size,
+ psz / SZ_1K, (int)shr >> GITS_BASER_SHAREABILITY_SHIFT);
+
+ return 0;
+}
+
static int its_alloc_tables(const char *node_name, struct its_node *its)
{
- int err;
- int i;
- int psz = SZ_64K;
+ u64 typer = readq_relaxed(its->base + GITS_TYPER);
+ u32 ids = GITS_TYPER_DEVBITS(typer);
u64 shr = GITS_BASER_InnerShareable;
- u64 cache;
- u64 typer;
- u32 ids;
+ u64 cache = GITS_BASER_WaWb;
+ int psz = SZ_64K;
+ int err, i;

if (its->flags & ITS_FLAGS_WORKAROUND_CAVIUM_22375) {
/*
* erratum 22375: only alloc 8MB table size
* erratum 24313: ignore memory access type
*/
- cache = 0;
+ cache = GITS_BASER_nCnB;
ids = 0x14; /* 20 bits, 8MB */
- } else {
- cache = GITS_BASER_WaWb;
- typer = readq_relaxed(its->base + GITS_TYPER);
- ids = GITS_TYPER_DEVBITS(typer);
}

its->device_ids = ids;
@@ -853,13 +963,16 @@ static int its_alloc_tables(const char *node_name, struct its_node *its)
u64 type = GITS_BASER_TYPE(val);
u64 entry_size = GITS_BASER_ENTRY_SIZE(val);
int order = get_order(psz);
- int alloc_pages;
- u64 tmp;
- void *base;
+ struct its_baser *baser = its->tables + i;

if (type == GITS_BASER_TYPE_NONE)
continue;

+ /* Set preferred settings for this BASERn */
+ baser->hwreg = its->base + GITS_BASER + i * 8;
+ baser->val = cache | shr;
+ baser->psz = psz;
+
/*
* Allocate as many entries as required to fit the
* range of device IDs that the ITS can grok... The ID
@@ -875,115 +988,28 @@ static int its_alloc_tables(const char *node_name, struct its_node *its)
* smaller than that. If the requested allocation
* is smaller, round up to the default page granule.
*/
- order = max(get_order((1UL << ids) * entry_size),
- order);
+ order = max(get_order(entry_size << ids), order);
if (order >= MAX_ORDER) {
order = MAX_ORDER - 1;
- pr_warn("%s: Device Table too large, reduce its page order to %u\n",
- node_name, order);
- }
- }
-
-retry_alloc_baser:
- alloc_pages = (PAGE_ORDER_TO_SIZE(order) / psz);
- if (alloc_pages > GITS_BASER_PAGES_MAX) {
- alloc_pages = GITS_BASER_PAGES_MAX;
- order = get_order(GITS_BASER_PAGES_MAX * psz);
- pr_warn("%s: Device Table too large, reduce its page order to %u (%u pages)\n",
- node_name, order, alloc_pages);
- }
-
- base = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
- if (!base) {
- err = -ENOMEM;
- goto out_free;
- }
-
- its->tables[i].base = base;
- its->tables[i].order = order;
-
-retry_baser:
- val = (virt_to_phys(base) |
- (type << GITS_BASER_TYPE_SHIFT) |
- ((entry_size - 1) << GITS_BASER_ENTRY_SIZE_SHIFT) |
- cache |
- shr |
- GITS_BASER_VALID);
-
- switch (psz) {
- case SZ_4K:
- val |= GITS_BASER_PAGE_SIZE_4K;
- break;
- case SZ_16K:
- val |= GITS_BASER_PAGE_SIZE_16K;
- break;
- case SZ_64K:
- val |= GITS_BASER_PAGE_SIZE_64K;
- break;
- }
-
- val |= alloc_pages - 1;
- its->tables[i].val = val;
-
- writeq_relaxed(val, its->base + GITS_BASER + i * 8);
- tmp = readq_relaxed(its->base + GITS_BASER + i * 8);
-
- if ((val ^ tmp) & GITS_BASER_SHAREABILITY_MASK) {
- /*
- * Shareability didn't stick. Just use
- * whatever the read reported, which is likely
- * to be the only thing this redistributor
- * supports. If that's zero, make it
- * non-cacheable as well.
- */
- shr = tmp & GITS_BASER_SHAREABILITY_MASK;
- if (!shr) {
- cache = GITS_BASER_nC;
- __flush_dcache_area(base, PAGE_ORDER_TO_SIZE(order));
+ ids = ilog2(PAGE_ORDER_TO_SIZE(order) / entry_size);
+ pr_warn("ITS@%lx:: Device Table too large, reduce ids %u->%u\n",
+ its->phys_base, its->device_ids, ids);
}
- goto retry_baser;
}

- if ((val ^ tmp) & GITS_BASER_PAGE_SIZE_MASK) {
- /*
- * Page size didn't stick. Let's try a smaller
- * size and retry. If we reach 4K, then
- * something is horribly wrong...
- */
- free_pages((unsigned long)base, order);
- its->tables[i].base = NULL;
-
- switch (psz) {
- case SZ_16K:
- psz = SZ_4K;
- goto retry_alloc_baser;
- case SZ_64K:
- psz = SZ_16K;
- goto retry_alloc_baser;
- }
- }
-
- if (val != tmp) {
- pr_err("ITS: %s: GITS_BASER%d doesn't stick: %lx %lx\n",
- node_name, i,
- (unsigned long) val, (unsigned long) tmp);
- err = -ENXIO;
- goto out_free;
+ err = its_baser_setup(its, baser, order, 0);
+ if (err < 0) {
+ its_free_tables(its);
+ return err;
}

- pr_info("ITS: allocated %d %s @%lx (psz %dK, shr %d)\n",
- (int)(PAGE_ORDER_TO_SIZE(order) / entry_size),
- its_base_type_string[type],
- (unsigned long)virt_to_phys(base),
- psz / SZ_1K, (int)shr >> GITS_BASER_SHAREABILITY_SHIFT);
+ /* Update settings which will be used for next BASERn */
+ psz = baser->psz;
+ cache = baser->val & GITS_BASER_CACHEABILITY_MASK;
+ shr = baser->val & GITS_BASER_SHAREABILITY_MASK;
}

return 0;
-
-out_free:
- its_free_tables(its);
-
- return err;
}

static int its_alloc_collections(struct its_node *its)
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index 9e6fdd3..7f917b9 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -204,6 +204,7 @@
#define GITS_BASER_NR_REGS 8

#define GITS_BASER_VALID (1UL << 63)
+#define GITS_BASER_INDIRECT (1UL << 62)
#define GITS_BASER_nCnB (0UL << 59)
#define GITS_BASER_nC (1UL << 59)
#define GITS_BASER_RaWt (2UL << 59)
@@ -228,6 +229,7 @@
#define GITS_BASER_PAGE_SIZE_64K (2UL << GITS_BASER_PAGE_SIZE_SHIFT)
#define GITS_BASER_PAGE_SIZE_MASK (3UL << GITS_BASER_PAGE_SIZE_SHIFT)
#define GITS_BASER_PAGES_MAX 256
+#define GITS_BASER_PAGES_SHIFT (0)

#define GITS_BASER_TYPE_NONE 0
#define GITS_BASER_TYPE_DEVICE 1
@@ -238,6 +240,7 @@
#define GITS_BASER_TYPE_RESERVED6 6
#define GITS_BASER_TYPE_RESERVED7 7

+#define GITS_LVL1_ENTRY_SIZE (8UL)
/*
* ITS commands
*/
--
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
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