[pull] master from torvalds:master #1948
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The DMA memory for this driver is allocated using dma_alloc_coherent(), which ends up mapping the allocated memory as uncached. Performing the various dma_sync_*() operations on this memory causes issues during SPI flashing: [ 7.818017] pc : dcache_inval_poc+0x40/0x58 [ 7.822128] lr : arch_sync_dma_for_cpu+0x2c/0x4c [ 7.826854] sp : ffff80008193bcf0 [ 7.830267] x29: ffff80008193bcf0 x28: ffffa3fe5ff1e908 x27: ffffa3fe627bb130 [ 7.837528] x26: ffff000086952180 x25: ffff00008015c8ac x24: ffff000086c9b480 [ 7.844878] x23: ffff00008015c800 x22: 0000000000000002 x21: 0000000000010000 [ 7.852229] x20: 0000000106dae000 x19: ffff000080112410 x18: 0000000000000001 [ 7.859580] x17: ffff000080159400 x16: ffffa3fe607a9bd8 x15: ffff0000eac1b180 [ 7.866753] x14: 000000000000000c x13: 0000000000000001 x12: 000000000000025a [ 7.874104] x11: 0000000000000000 x10: 7f73e96357f6a07f x9 : db1fc8072a7f5e3a [ 7.881365] x8 : ffff000086c9c588 x7 : ffffa3fe607a9bd8 x6 : ffff80008193bc28 [ 7.888630] x5 : 000000000000ffff x4 : 0000000000000009 x3 : 000000000000003f [ 7.895892] x2 : 0000000000000040 x1 : ffff000086dbe000 x0 : ffff000086db0000 [ 7.903155] Call trace: [ 7.905606] dcache_inval_poc+0x40/0x58 (P) [ 7.909804] iommu_dma_sync_single_for_cpu+0xb4/0xb8 [ 7.914617] __dma_sync_single_for_cpu+0x158/0x194 [ 7.919428] __this_module+0x5b020/0x5baf8 [spi_tegra210_quad] [ 7.925291] irq_thread_fn+0x2c/0xc0 [ 7.928966] irq_thread+0x16c/0x318 [ 7.932467] kthread+0x12c/0x214 Fix this by removing all calls to the dma_sync_*() functions. This isn't ideal because DMA is used only for relatively large (> 64 words or 256 bytes) and using uncached memory for this might be slow. Reworking this to use cached memory for faster access and reintroducing the cache maintenance calls is probably worth a follow-up patch. Reported-by: Brad Griffis <[email protected]> Fixes: 017f1b0 ("spi: tegra210-quad: Add support for internal DMA") Signed-off-by: Thierry Reding <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Mark Brown <[email protected]>
The datasheets for all the fan53555 variants (and clones using the same interface) define so called soft start times, from enabling the regulator until at least some percentage of the output (i.e. 92% for the rk860x types) are available. The regulator framework supports this with the enable_time property but currently the fan53555 driver does not define enable_times for any variant. I ran into a problem with this while testing the new driver for the Rockchip NPUs (rocket), which does runtime-pm including disabling and enabling a rk8602 as needed. When reenabling the regulator while running a load, fatal hangs could be observed while enabling the associated power-domain, which the regulator supplies. Experimentally setting the regulator to always-on, made the issue disappear, leading to the missing delay to let power stabilize. And as expected, setting the enable-time to a non-zero value according to the datasheet also resolved the regulator-issue. The datasheets in nearly all cases only specify "typical" values, except for the fan53555 type 08. There both a typical and maximum value are listed - 40uS apart. For all typical values I've added 100uS to be on the safe side. Individual details for the relevant regulators below: - fan53526: The datasheet for all variants lists a typical value of 150uS, so make that 250uS with safety margin. - fan53555: types 08 and 18 (unsupported) are given a typical enable time of 135uS but also a maximum of 175uS so use that value. All the other types only have a typical time in the datasheet of 300uS, so give a bit margin by setting it to 400uS. - rk8600 + rk8602: Datasheet reports a typical value of 260us, so use 360uS to be safe. - syr82x + syr83x: All datasheets report typical soft-start values of 300uS for these regulators, so use 400uS. - tcs452x: Datasheet sadly does not report a soft-start time, so I've not set an enable-time Signed-off-by: Heiko Stuebner <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Mark Brown <[email protected]>
…inux/kernel/git/broonie/regulator Pull regulator fix from Mark Brown: "One patch here from Heiko which fixes stability issues on some Rockchip platforms by implementing soft start support and providing startup time information for their regulators" * tag 'regulator-fix-v6.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator: regulator: fan53555: add enable_time support and soft-start times
…ernel/git/broonie/spi Pull spi fix from Mark Brown: "One fix here from Thierry, fixing crashes caused by attempting to do cache sync operations on uncached memory on Tegra platforms" * tag 'spi-fix-v6.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: spi: tegra210-qspi: Remove cache operations
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