On 7/30/24 10:39, Krzysztof Kozlowski wrote: > On 30/07/2024 10:23, Krzysztof Kozlowski wrote: >> On 29/07/2024 16:25, Pierre-Louis Bossart wrote: >>> >>> >>> On 7/29/24 16:01, Krzysztof Kozlowski wrote: >>>> Two bitmasks in 'struct sdw_slave_prop' - 'source_ports' and >>>> 'sink_ports' - define which ports to program in >>>> sdw_program_slave_port_params(). The masks are used to get the >>>> appropriate data port properties ('struct sdw_get_slave_dpn_prop') from >>>> an array. >>>> >>>> Bitmasks can be non-continuous or can start from index different than 0, >>>> thus when looking for matching port property for given port, we must >>>> iterate over mask bits, not from 0 up to number of ports. >>>> >>>> This fixes allocation and programming slave ports, when a source or sink >>>> masks start from further index. >>>> >>>> Fixes: f8101c74aa54 ("soundwire: Add Master and Slave port programming") >>>> Cc: <stable@xxxxxxxxxxxxxxx> >>>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> >>> >>> This is a valid change to optimize how the port are accessed. >>> >>> But the commit message is not completely clear, the allocation in >>> mipi_disco.c is not modified and I don't think there's anything that >>> would crash. If there are non-contiguous ports, we will still allocate >>> space that will not be initialized/used. >>> >>> /* Allocate memory for set bits in port lists */ >>> nval = hweight32(prop->source_ports); >>> prop->src_dpn_prop = devm_kcalloc(&slave->dev, nval, >>> sizeof(*prop->src_dpn_prop), >>> GFP_KERNEL); >>> if (!prop->src_dpn_prop) >>> return -ENOMEM; >>> >>> /* Read dpn properties for source port(s) */ >>> sdw_slave_read_dpn(slave, prop->src_dpn_prop, nval, >>> prop->source_ports, "source"); >>> >>> IOW, this is a valid change, but it's an optimization, not a fix in the >>> usual sense of 'kernel oops otherwise'. >>> >>> Am I missing something? >>> >>> BTW, the notion of DPn is that n > 0. DP0 is a special case with >>> different properties, BIT(0) cannot be set for either of the sink/source >>> port bitmask. >> >> I think we speak about two different things. port num > 1, that's >> correct. But index for src_dpn_prop array is something different. Look >> at mipi-disco sdw_slave_read_dpn(): >> >> 173 u32 bit, i = 0; >> ... >> 178 addr = ports; >> 179 /* valid ports are 1 to 14 so apply mask */ >> 180 addr &= GENMASK(14, 1); >> 181 >> 182 for_each_set_bit(bit, &addr, 32) { >> ... >> 186 dpn[i].num = bit; >> >> >> so dpn[0..i] = 1..n >> where i is also the bit in the mask. yes, agreed on the indexing. But are we in agreement that the case of non-contiguous ports would not create any issues? the existing code is not efficient but it wouldn't crash, would it? There are multiple cases of non-contiguous ports, I am not aware of any issues... rt700-sdw.c: prop->source_ports = 0x14; /* BITMAP: 00010100 */ rt711-sdca-sdw.c: prop->source_ports = 0x14; /* BITMAP: 00010100 rt712-sdca-sdw.c: prop->source_ports = BIT(8) | BIT(4); rt715-sdca-sdw.c: prop->source_ports = 0x50;/* BITMAP: 01010000 */ rt722-sdca-sdw.c: prop->source_ports = BIT(6) | BIT(2); /* BITMAP: 01000100 */ same for sinks: rt712-sdca-sdw.c: prop->sink_ports = BIT(3) | BIT(1); /* BITMAP: 00001010 */ rt722-sdca-sdw.c: prop->sink_ports = BIT(3) | BIT(1); /* BITMAP: 00001010 */ >> Similar implementation was done in Qualcomm wsa and wcd codecs like: >> array indexed from 0: >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/soc/codecs/wcd938x-sdw.c?h=v6.11-rc1#n51 >> >> genmask from 0, with a mistake: >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/soc/codecs/wcd938x-sdw.c?h=v6.11-rc1#n1255 >> >> The mistake I corrected here: >> https://lore.kernel.org/all/20240726-asoc-wcd-wsa-swr-ports-genmask-v1-0-d4d7a8b56f05@xxxxxxxxxx/ >> >> To summarize, the mask does not denote port numbers (1...14) but indices >> of the dpn array which are from 0..whatever (usually -1 from port number). >> > > Let me also complete this with a real life example of my work in > progress. I want to use same dpn_prop array for sink and source ports > and use different masks. The code in progress is: > > https://git.codelinaro.org/krzysztof.kozlowski/linux/-/commit/ef709a0e8ab2498751305367e945df18d7a05c78#6f965d7b74e712a5cfcbc1cca407b85443a66bac_2147_2157 > > Without this patch, I get -EINVAL from sdw_get_slave_dpn_prop(): > soundwire sdw-master-1-0: Program transport params failed: -2 Not following, sorry. The sink and source masks are separate on purpose, to allow for bi-directional ports. The SoundWire spec allows a port to be configured at run-time either as source or sink. In practice I've never seen this happen, all existing hardware relies on ports where the direction is hard-coded/fixed, but still we want to follow the spec. So if ports can be either source or sink, I am not sure how the properties could be shared with a single array? Those two lines aren't clear to me at all: pdev->prop.sink_dpn_prop = wsa884x_sink_dpn_prop; pdev->prop.src_dpn_prop = wsa884x_sink_dpn_prop;