Messages in this thread | | | Subject | Re: [PATCH 06/17] coresight: tmc: Make ETR SG table circular | From | Suzuki K Poulose <> | Date | Thu, 2 Nov 2017 12:00:51 +0000 |
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On 01/11/17 23:47, Mathieu Poirier wrote: > On Thu, Oct 19, 2017 at 06:15:42PM +0100, Suzuki K Poulose wrote: >> Make the ETR SG table Circular buffer so that we could start >> at any of the SG pages and use the entire buffer for tracing. >> This can be achieved by : >> >> 1) Keeping an additional LINK pointer at the very end of the >> SG table, i.e, after the LAST buffer entry, to point back to >> the beginning of the first table. This will allow us to use >> the buffer normally when we start the trace at offset 0 of >> the buffer, as the LAST buffer entry hints the TMC-ETR and >> it automatically wraps to the offset 0. >> >> 2) If we want to start at any other ETR SG page aligned offset, >> we could : >> a) Make the preceding page entry as LAST entry. >> b) Make the original LAST entry a normal entry. >> c) Use the table pointer to the "new" start offset as the >> base of the table address. >> This works as the TMC doesn't mandate that the page table >> base address should be 4K page aligned. >> >> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> >> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> >> ---
>> +static int __maybe_unused >> +tmc_etr_sg_table_rotate(struct etr_sg_table *etr_table, u64 base_offset) >> +{ >> + u32 last_entry, first_entry; >> + u64 last_offset; >> + struct tmc_sg_table *sg_table = etr_table->sg_table; >> + sgte_t *table_ptr = sg_table->table_vaddr; >> + ssize_t buf_size = tmc_sg_table_buf_size(sg_table); >> + >> + /* Offset should always be SG PAGE_SIZE aligned */ >> + if (base_offset & (ETR_SG_PAGE_SIZE - 1)) { >> + pr_debug("unaligned base offset %llx\n", base_offset); >> + return -EINVAL; >> + } >> + /* Make sure the offset is within the range */ >> + if (base_offset < 0 || base_offset > buf_size) { >> + base_offset = (base_offset + buf_size) % buf_size; >> + pr_debug("Resetting offset to %llx\n", base_offset); >> + } >> + first_entry = tmc_etr_sg_offset_to_table_index(base_offset); >> + if (first_entry == etr_table->first_entry) { >> + pr_debug("Head is already at %llx, skipping\n", base_offset); >> + return 0; >> + } >> + >> + /* Last entry should be the previous one to the new "base" */ >> + last_offset = ((base_offset - ETR_SG_PAGE_SIZE) + buf_size) % buf_size; >> + last_entry = tmc_etr_sg_offset_to_table_index(last_offset); >> + >> + /* Reset the current Last page to Normal and new Last page to NORMAL */ >> + tmc_etr_sg_update_type(&table_ptr[etr_table->last_entry], >> + ETR_SG_ET_NORMAL); >> + tmc_etr_sg_update_type(&table_ptr[last_entry], ETR_SG_ET_LAST); >> + etr_table->hwaddr = tmc_etr_sg_table_index_to_daddr(sg_table, >> + first_entry); >> + etr_table->first_entry = first_entry; >> + etr_table->last_entry = last_entry; >> + pr_debug("table rotated to offset %llx-%llx, entries (%d - %d), dba: %llx\n", >> + base_offset, last_offset, first_entry, last_entry, >> + etr_table->hwaddr); > > The above line generates a warning when compiling for ARMv7.
Where you running with LPAE off ? That could probably be the case, where hwaddr could be 32bit or 64bit depending on whether LPAE is enabled. I will fix it.
I have fixed some other warnings with ARMv7 with LPAE.
Suzuki
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