Re: [PATCH] Fixes: 1d7afc9 i2c: omap: ack IRQ in parts

[Alexander Kochetkov]

That's RESEND

Previous one patch was:
i2c: omap: fix NACK and Arbitration Lost irq handling
http://www.spinics.net/lists/linux-i2c/msg17490.html

I'll made more testing of current (linux/master) i2c driver (without my patch) and here I
send test results.

For traces I used custom patch attached to the e-mail.

For simulating I2C bus conditions, I used simple MCU connected to Beagleboard 
using I2C bus. MCU can act as slave and as master, and Beagleboard can instruct MCU
to setup special conditions on the bus.

I used oscilloscope to control signals on wire.

The results indicates what:
1. current i2c driver actually doesn't cause controller hang and client code segfaults.
   (my previous patch incorrectly blame that)

2. it looks, that current i2c, doesn't strictly follow TI specs (AM-DM37x Multimedia Device 
   Silicon Revision 1.x  - sprugn4r, Figure 17-31. HS I2C Master Transmitter Mode ... and
   Figure 17-32. HS I2C Master Receiver Mode ..., note 1)
   
3. current i2c driver keeps processing interrupts after it call omap_i2c_complete_cmd.
4. in NACK case current driver call omap_i2c_complete_cmd two times.

The patch fixes 2, 3, 4.

Here how spotted problems looks like.

i2c controller initiate master write transfer to slave device what doesn't exist on the i2c bus.
(isr thread keeps processing interrupts (ARDY) after it signaled transfer completion, and call complete second time)
=========================
[ 2481.152770] omap_i2c omap_i2c.2: addr: 0x0068, len: 4, flags: 0x0, stop: 1
[ 2481.152801] omap_i2c omap_i2c.2: Pre submit: STAT=0x0100; IE=0x601f; CON=0x8000 (omap_i2c_xfer_msg:584)
[ 2481.152832] omap_i2c omap_i2c.2: Hard ISR: STAT=0x1110; IE=0x601f; CON=0x8602 (omap_i2c_isr:911)
[ 2481.152862] omap_i2c omap_i2c.2: Post submit: STAT=0x1110; IE=0x601f; CON=0x8602 (omap_i2c_xfer_msg:586)
[ 2481.152893] omap_i2c omap_i2c.2: Wait comlete: STAT=0x1110; IE=0x601f; CON=0x8602 (omap_i2c_xfer_msg:615)
[ 2481.152923] omap_i2c omap_i2c.2: Thread ISR: STAT=0x1112; IE=0x601f; CON=0x8602 (omap_i2c_isr_thread:936)
[ 2481.152954] omap_i2c omap_i2c.2: IRQ (ISR = 0x0012)
[ 2481.152954] omap_i2c omap_i2c.2: Complete: STAT=0x0114; IE=0x601f; CON=0x8200 (omap_i2c_isr_thread:1055)
[ 2481.152984] omap_i2c omap_i2c.2: Hard ISR: STAT=0x0114; IE=0x601f; CON=0x8200 (omap_i2c_isr:911)
[ 2481.153015] omap_i2c omap_i2c.2: Thread ISR: STAT=0x0114; IE=0x601f; CON=0x8200 (omap_i2c_isr_thread:936)
[ 2481.153015] omap_i2c omap_i2c.2: IRQ (ISR = 0x0014)
[ 2481.153045] omap_i2c omap_i2c.2: Complete: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_isr_thread:1055)
[ 2481.153106] omap_i2c omap_i2c.2: Got comlete: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_xfer_msg:618)
[ 2481.153106] omap_i2c omap_i2c.2: Got NACK - send STP: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_xfer_msg:642)

i2c controller initiate master read transfer to slave device what doesn't exist on the i2c bus.
(isr thread keeps processing interrupts (ARDY) after it signaled transfer completion, and call complete second time)
=========================
[ 3201.693603] omap_i2c omap_i2c.2: addr: 0x0068, len: 4, flags: 0x1, stop: 1
[ 3201.693603] omap_i2c omap_i2c.2: Pre submit: STAT=0x0100; IE=0x601f; CON=0x8000 (omap_i2c_xfer_msg:584)
[ 3201.693634] omap_i2c omap_i2c.2: Post submit: STAT=0x0100; IE=0x601f; CON=0x8403 (omap_i2c_xfer_msg:586)
[ 3201.693634] omap_i2c omap_i2c.2: Wait comlete: STAT=0x1100; IE=0x601f; CON=0x8402 (omap_i2c_xfer_msg:615)
[ 3201.693756] omap_i2c omap_i2c.2: Hard ISR: STAT=0x0106; IE=0x601f; CON=0x8000 (omap_i2c_isr:911)
[ 3201.693847] omap_i2c omap_i2c.2: Thread ISR: STAT=0x0106; IE=0x601f; CON=0x8000 (omap_i2c_isr_thread:936)
[ 3201.693847] omap_i2c omap_i2c.2: IRQ (ISR = 0x0006)
[ 3201.693878] omap_i2c omap_i2c.2: Complete: STAT=0x0104; IE=0x601f; CON=0x8000 (omap_i2c_isr_thread:1055)
[ 3201.693908] omap_i2c omap_i2c.2: Hard ISR: STAT=0x0104; IE=0x601f; CON=0x8000 (omap_i2c_isr:911)
[ 3201.693908] omap_i2c omap_i2c.2: Thread ISR: STAT=0x0104; IE=0x601f; CON=0x8000 (omap_i2c_isr_thread:936)
[ 3201.693939] omap_i2c omap_i2c.2: IRQ (ISR = 0x0004)
[ 3201.693939] omap_i2c omap_i2c.2: Complete: STAT=0x0100; IE=0x601f; CON=0x8000 (omap_i2c_isr_thread:1055)
[ 3201.693969] omap_i2c omap_i2c.2: Got comlete: STAT=0x0100; IE=0x601f; CON=0x8000 (omap_i2c_xfer_msg:618)
[ 3201.694000] omap_i2c omap_i2c.2: Got NACK - send STP: STAT=0x0100; IE=0x601f; CON=0x8000 (omap_i2c_xfer_msg:642)

i2c controller initiate master write transfer to slave device and get NACK on the second data byte (address and first data bytes
transmit successfully).
(isr thread keeps processing interrupts (ARDY) after it signaled transfer completion, and call complete second time)
=========================
[ 3457.679901] omap_i2c omap_i2c.2: addr: 0x0058, len: 4, flags: 0x0, stop: 1
[ 3457.679931] omap_i2c omap_i2c.2: Pre submit: STAT=0x0100; IE=0x601f; CON=0x8000 (omap_i2c_xfer_msg:584)
[ 3457.679962] omap_i2c omap_i2c.2: Hard ISR: STAT=0x0110; IE=0x601f; CON=0x8602 (omap_i2c_isr:911)
[ 3457.679992] omap_i2c omap_i2c.2: Post submit: STAT=0x1110; IE=0x601f; CON=0x8602 (omap_i2c_xfer_msg:586)
[ 3457.680175] omap_i2c omap_i2c.2: Wait comlete: STAT=0x1510; IE=0x601f; CON=0x8602 (omap_i2c_xfer_msg:615)
[ 3457.680236] omap_i2c omap_i2c.2: Thread ISR: STAT=0x1510; IE=0x601f; CON=0x8602 (omap_i2c_isr_thread:936)
[ 3457.680267] omap_i2c omap_i2c.2: IRQ (ISR = 0x0010)
[ 3457.680267] omap_i2c omap_i2c.2: Thread ISR: STAT=0x1100; IE=0x601f; CON=0x8602 (omap_i2c_isr_thread:936)
[ 3457.680480] omap_i2c omap_i2c.2: Hard ISR: STAT=0x1102; IE=0x601f; CON=0x8602 (omap_i2c_isr:911)
[ 3457.680603] omap_i2c omap_i2c.2: Thread ISR: STAT=0x0106; IE=0x601f; CON=0x8200 (omap_i2c_isr_thread:936)
[ 3457.680603] omap_i2c omap_i2c.2: IRQ (ISR = 0x0006)
[ 3457.680633] omap_i2c omap_i2c.2: Complete: STAT=0x0104; IE=0x601f; CON=0x8200 (omap_i2c_isr_thread:1055)
[ 3457.680664] omap_i2c omap_i2c.2: Hard ISR: STAT=0x0104; IE=0x601f; CON=0x8200 (omap_i2c_isr:911)
[ 3457.680694] omap_i2c omap_i2c.2: Thread ISR: STAT=0x0104; IE=0x601f; CON=0x8200 (omap_i2c_isr_thread:936)
[ 3457.680694] omap_i2c omap_i2c.2: IRQ (ISR = 0x0004)
[ 3457.680694] omap_i2c omap_i2c.2: Complete: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_isr_thread:1055)
[ 3457.683288] omap_i2c omap_i2c.2: Got comlete: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_xfer_msg:618)
[ 3457.683319] omap_i2c omap_i2c.2: Got NACK - send STP: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_xfer_msg:642)

i2c controller initiate master write transfer to slave device and get AL during address phase
(isr thread keeps processing interrupts (XRDY) after it signaled transfer completion)
=========================
[ 3969.863067] omap_i2c omap_i2c.2: addr: 0x0058, len: 4, flags: 0x0, stop: 1
[ 3969.863067] omap_i2c omap_i2c.2: Pre submit: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_xfer_msg:584)
[ 3969.863098] omap_i2c omap_i2c.2: Hard ISR: STAT=0x0110; IE=0x601f; CON=0x8602 (omap_i2c_isr:911)
[ 3969.863128] omap_i2c omap_i2c.2: Post submit: STAT=0x1111; IE=0x601f; CON=0x8200 (omap_i2c_xfer_msg:586)
[ 3969.863128] omap_i2c omap_i2c.2: Wait comlete: STAT=0x1111; IE=0x601f; CON=0x8200 (omap_i2c_xfer_msg:615)
[ 3969.863159] omap_i2c omap_i2c.2: Thread ISR: STAT=0x1111; IE=0x601f; CON=0x8200 (omap_i2c_isr_thread:936)
[ 3969.863189] omap_i2c omap_i2c.2: IRQ (ISR = 0x0011)
[ 3969.863189] omap_i2c omap_i2c.2: Arbitration lost
[ 3969.868103] omap_i2c omap_i2c.2: Complete: STAT=0x0110; IE=0x601f; CON=0x8200 (omap_i2c_isr_thread:1055)
[ 3969.868316] omap_i2c omap_i2c.2: Hard ISR: STAT=0x0110; IE=0x601f; CON=0x8200 (omap_i2c_isr:911)
[ 3969.868347] omap_i2c omap_i2c.2: Thread ISR: STAT=0x0110; IE=0x601f; CON=0x8200 (omap_i2c_isr_thread:936)
[ 3969.868347] omap_i2c omap_i2c.2: IRQ (ISR = 0x0010)
[ 3969.868377] omap_i2c omap_i2c.2: Thread ISR: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_isr_thread:936)
[ 3969.875518] omap_i2c omap_i2c.2: Got comlete: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_xfer_msg:618)
[ 3969.875549] omap_i2c omap_i2c.2: Got AL - i2c reset: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_xfer_msg:632)

i2c controller initiate master read transfer to slave device and get AL during address phase.
(that case works as expected)
=========================
[ 4136.002380] omap_i2c omap_i2c.2: addr: 0x0058, len: 4, flags: 0x1, stop: 1
[ 4136.002380] omap_i2c omap_i2c.2: Pre submit: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_xfer_msg:584)
[ 4136.002410] omap_i2c omap_i2c.2: Post submit: STAT=0x0100; IE=0x601f; CON=0x8403 (omap_i2c_xfer_msg:586)
[ 4136.002410] omap_i2c omap_i2c.2: Wait comlete: STAT=0x1100; IE=0x601f; CON=0x8402 (omap_i2c_xfer_msg:615)
[ 4136.002593] omap_i2c omap_i2c.2: Hard ISR: STAT=0x1101; IE=0x601f; CON=0x8000 (omap_i2c_isr:911)
[ 4136.002655] omap_i2c omap_i2c.2: Thread ISR: STAT=0x0101; IE=0x601f; CON=0x8000 (omap_i2c_isr_thread:936)
[ 4136.002655] omap_i2c omap_i2c.2: IRQ (ISR = 0x0001)
[ 4136.002655] omap_i2c omap_i2c.2: Arbitration lost
[ 4136.007598] omap_i2c omap_i2c.2: Complete: STAT=0x0100; IE=0x601f; CON=0x8000 (omap_i2c_isr_thread:1055)
[ 4136.009674] omap_i2c omap_i2c.2: Got comlete: STAT=0x0100; IE=0x601f; CON=0x8000 (omap_i2c_xfer_msg:618)
[ 4136.009704] omap_i2c omap_i2c.2: Got AL - i2c reset: STAT=0x0100; IE=0x601f; CON=0x8000 (omap_i2c_xfer_msg:632)

i2c controller initiate master write transfer to slave device and get AL on the second data byte (address and first data bytes
transmit successfully).
(that case works as expected)
=========================
[ 4303.387481] omap_i2c omap_i2c.2: addr: 0x0058, len: 4, flags: 0x0, stop: 1
[ 4303.387512] omap_i2c omap_i2c.2: Pre submit: STAT=0x0000; IE=0x601f; CON=0x8000 (omap_i2c_xfer_msg:584)
[ 4303.387542] omap_i2c omap_i2c.2: Hard ISR: STAT=0x1010; IE=0x601f; CON=0x8602 (omap_i2c_isr:911)
[ 4303.387573] omap_i2c omap_i2c.2: Post submit: STAT=0x1010; IE=0x601f; CON=0x8602 (omap_i2c_xfer_msg:586)
[ 4303.387603] omap_i2c omap_i2c.2: Wait comlete: STAT=0x1010; IE=0x601f; CON=0x8602 (omap_i2c_xfer_msg:615)
[ 4303.387664] omap_i2c omap_i2c.2: Thread ISR: STAT=0x1410; IE=0x601f; CON=0x8602 (omap_i2c_isr_thread:936)
[ 4303.387664] omap_i2c omap_i2c.2: IRQ (ISR = 0x0010)
[ 4303.387695] omap_i2c omap_i2c.2: Thread ISR: STAT=0x1400; IE=0x601f; CON=0x8602 (omap_i2c_isr_thread:936)
[ 4303.388031] omap_i2c omap_i2c.2: Hard ISR: STAT=0x1001; IE=0x601f; CON=0x8200 (omap_i2c_isr:911)
[ 4303.388122] omap_i2c omap_i2c.2: Thread ISR: STAT=0x1001; IE=0x601f; CON=0x8200 (omap_i2c_isr_thread:936)
[ 4303.388122] omap_i2c omap_i2c.2: IRQ (ISR = 0x0001)
[ 4303.388153] omap_i2c omap_i2c.2: Arbitration lost
[ 4303.393066] omap_i2c omap_i2c.2: Complete: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_isr_thread:1055)
[ 4303.395141] omap_i2c omap_i2c.2: Got comlete: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_xfer_msg:618)
[ 4303.395172] omap_i2c omap_i2c.2: Got AL - i2c reset: STAT=0x0100; IE=0x601f; CON=0x8200 (omap_i2c_xfer_msg:632)

The patch for tracing.
=========================