Hi Marc,
On 06/04/2016 03:53 AM, Marc Zyngier wrote:
> On Mon, 9 May 2016 15:58:25 -0500
> Shanker Donthineni <shank...@codeaurora.org> wrote:
>
>> 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 <shank...@codeaurora.org>
>> ---
>> 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;
> I'm not overly fond of caching arbitrary device addresses, and I'd be
> happier if you had the GITS_BASERn index in there, together with a
> couple of helpers to perform the access:
>
> void its_write_baser(struct its_node *its, struct its_baser *baser,
> u64 val);
> u64 its_read_baser(struct its_node *its, struct its_baser *baser);
>
> and keep the offset computing out of sight.
Sure, I am happy to do this change and also helps the code readability.
>> 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)
> Please move the indirect support to the next patch. I'd like to see
> something that doesn't have any semantic change.
I'll move ITS-indirection related code logic to next patch.
>> +{
>> + 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 |
> See my comment on the next patch. This should be a bool, and used with
> something like:
> [...]
> indirect ? GITS_BASER_INDIRECT : 0 |
> [...]
>
> (and of course moved to the next patch, together with the rest of the
> indirect support.
I'll follow your suggestion and the corresponding changes will be moved to next
patch.
>> + 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;
> Patch #2
Sure.
>> +
>> + 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)
> Second patch as well.
Sure,
>> /*
>> * ITS commands
>> */
>
> Thanks,
>
> M.
--
Shanker Donthineni
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
