Messages in this thread | | | From | Mathieu Poirier <> | Date | Tue, 8 May 2018 10:13:54 -0600 | Subject | Re: [PATCH v2 18/27] coresight: catu: Add support for scatter gather tables |
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On 8 May 2018 at 09:56, Suzuki K Poulose <Suzuki.Poulose@arm.com> wrote: > On 07/05/18 21:25, Mathieu Poirier wrote: >> >> On Tue, May 01, 2018 at 10:10:48AM +0100, Suzuki K Poulose wrote: >>> >>> This patch adds the support for setting up a SG table for use >>> by the CATU. We reuse the tmc_sg_table to represent the table/data >>> pages, even though the table format is different. >>> > > ... > >>> >>> diff --git a/drivers/hwtracing/coresight/coresight-catu.c >>> b/drivers/hwtracing/coresight/coresight-catu.c >>> index 2cd69a6..4cc2928 100644 >>> --- a/drivers/hwtracing/coresight/coresight-catu.c >>> +++ b/drivers/hwtracing/coresight/coresight-catu.c >>> @@ -16,10 +16,419 @@ > > > ... > >>> + >>> +/* >>> + * Update the valid bit for a given range of indices [start, end) >>> + * in the given table @table. >>> + */ >>> +static inline void catu_update_state_range(cate_t *table, int start, >>> + int end, int valid) >> >> >> Indentation >> > > ... > >>> +#ifdef CATU_DEBUG >>> +static void catu_dump_table(struct tmc_sg_table *catu_table) >>> +{ >>> + int i; >>> + cate_t *table; >>> + unsigned long table_end, buf_size, offset = 0; >>> + >>> + buf_size = tmc_sg_table_buf_size(catu_table); >>> + dev_dbg(catu_table->dev, >>> + "Dump table %p, tdaddr: %llx\n", >>> + catu_table, catu_table->table_daddr); >>> + >>> + while (offset < buf_size) { >>> + table_end = offset + SZ_1M < buf_size ? >>> + offset + SZ_1M : buf_size; >>> + table = catu_get_table(catu_table, offset, NULL); >>> + for (i = 0; offset < table_end; i++, offset += >>> CATU_PAGE_SIZE) >>> + dev_dbg(catu_table->dev, "%d: %llx\n", i, >>> table[i]); >>> + dev_dbg(catu_table->dev, "Prev : %llx, Next: %llx\n", >>> + table[CATU_LINK_PREV], table[CATU_LINK_NEXT]); >>> + dev_dbg(catu_table->dev, "== End of sub-table ==="); >>> + } >>> + dev_dbg(catu_table->dev, "== End of Table ==="); >>> +} >>> + >>> +#else >>> +static inline void catu_dump_table(struct tmc_sg_table *catu_table) >>> +{ >>> +} >>> +#endif >> >> >> I think this approach is better than peppering the code with #ifdefs as it >> was >> done for ETR. Please fix that to replicate what you've done here. >> > > OK > >>> + >>> +/* >>> + * catu_populate_table : Populate the given CATU table. >>> + * The table is always populated as a circular table. >>> + * i.e, the "prev" link of the "first" table points to the "last" >>> + * table and the "next" link of the "last" table points to the >>> + * "first" table. The buffer should be made linear by calling >>> + * catu_set_table(). >>> + */ >>> +static void >>> +catu_populate_table(struct tmc_sg_table *catu_table) >>> +{ > > > ... > >>> + while (offset < buf_size) { >>> + /* >>> + * The @offset is always 1M aligned here and we have an >>> + * empty table @table_ptr to fill. Each table can address >>> + * upto 1MB data buffer. The last table may have fewer >>> + * entries if the buffer size is not aligned. >>> + */ >>> + last_offset = (offset + SZ_1M) < buf_size ? >>> + (offset + SZ_1M) : buf_size; >>> + for (i = 0; offset < last_offset; i++) { >>> + >>> + data_daddr = catu_table->data_pages.daddrs[dpidx] >>> + >>> + s_dpidx * CATU_PAGE_SIZE; >>> +#ifdef CATU_DEBUG >>> + dev_dbg(catu_table->dev, >>> + "[table %5d:%03d] 0x%llx\n", >>> + (offset >> 20), i, data_daddr); >>> +#endif >> >> >> I'm not a fan of adding #ifdefs in the code like this. I think it is >> better to >> have a wrapper (that resolves to nothing if CATU_DEBUG is not defined) and >> handle the output in there. >> > > >>> + >>> + catu_populate_table(catu_table); >>> + /* Make the buf linear from offset 0 */ >>> + (void)catu_set_table(catu_table, 0, size); >>> + >>> + dev_dbg(catu_dev, >>> + "Setup table %p, size %ldKB, %d table pages\n", >>> + catu_table, (unsigned long)size >> 10, nr_tpages); >> >> >> I think this should also be wrapped in a special output debug function. >> > > I could do something like : > > #ifdef CATU_DEBUG > #define catu_dbg(fmt, ...) dev_dbg(fmt, __VA_ARGS__) > #else > #define catu_dbg(fmt, ...) do { } while (0) > #endif > > And use catu_dbg() for the sprinkled prints.
Yes, that is exactly what I had in mind.
> > Cheers > Suzuki
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