ot_i2c: Implement Target Mode Address Masking
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hw/opentitan/ot_i2c.c
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| s->address_mask = mask; | ||
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| if (mask != 0u && address != 0u) { | ||
| ARRAY_FIELD_DP32(s->regs, TARGET_ID, ADDRESS0, address); |
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Aside: is the existing code correct here? Should we only be updating the address field and the I2C address on the bus if non-zero? We shouldn't match the address if the mask is non-zero (even though that should probably be handled in match_and_add instead), but we should probably still reflect the write in the register at least. Is there a way to de-register the device instead of just setting its address?
Also, sorry I missed this in previous PRs, but do we need to also i2c_slave_set_address(s->target, 0u) on reset to match the resetval? Or is this behaviour already implemented by resetting the I2C bus?
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Is there a way to de-register the device instead of just setting its address?
I do not think so.addressis a property ofI2CSlaveClass.
There is some weirdness around address 0 as QEMU uses it as a "broadcast" address (hw/i2c/core.c) - it uses that to make the default i2c_slave_match add each I2C device.
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ot_i2c: Implement Target Mode Address Masking
This implements target mode address masking as described in the documentation - OT I2C target mode will accept a transaction if the bitwise AND of an address and the device's address mask matches the device's address. This is implemented by overriding the default `I2CSlaveClass` `match_and_add` method. See `i2c_slave_match` in `hw/i2c/core.c`. Signed-off-by: Alice Ziuziakowska <a.ziuziakowska@lowrisc.org>
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This implements target mode address masking as described in the documentation - OT I2C target mode will accept a transaction if the bitwise AND of an address and the device's address mask matches the device's address.
This is implemented by overriding the default
I2CSlaveClassmatch_and_addmethod. Seei2c_slave_matchinhw/i2c/core.c.