hw/dma: sifive_pdma: don't set Control.error if 0 bytes to transfer
Real PDMA doesn't set Control.error if there are 0 bytes to be
transferred. The DMA transfer is still success.
The following result is PDMA tested in U-Boot on Unmatched board:
=> mw.l 0x3000000 0x0 <= Disclaim channel 0
=> mw.l 0x3000000 0x1 <= Claim channel 0
=> mw.l 0x3000004 0x55000000 <= wsize = rsize = 5 (2^5 = 32 bytes)
=> mw.q 0x3000008 0x0 <= NextBytes = 0
=> mw.q 0x3000010 0x84000000 <= NextDestination = 0x84000000
=> mw.q 0x3000018 0x84001000 <= NextSource = 0x84001000
=> mw.l 0x84000000 0x87654321 <= Fill test data to dst
=> mw.l 0x84001000 0x12345678 <= Fill test data to src
=> md.l 0x84000000 1; md.l 0x84001000 1 <= Dump src/dst memory contents
84000000:
87654321 !Ce.
84001000:
12345678 xV4.
=> md.l 0x3000000 8 <= Dump PDMA status
03000000:
00000001 55000000 00000000 00000000 .......U........
03000010:
84000000 00000000 84001000 00000000 ................
=> mw.l 0x3000000 0x3 <= Set channel 0 run and claim bits
=> md.l 0x3000000 8 <= Dump PDMA status
03000000:
40000001 55000000 00000000 00000000 ...@...U........
03000010:
84000000 00000000 84001000 00000000 ................
=> md.l 0x84000000 1; md.l 0x84001000 1 <= Dump src/dst memory contents
84000000:
87654321 !Ce.
84001000:
12345678 xV4.
Signed-off-by: Frank Chang <frank.chang@sifive.com>
Tested-by: Max Hsu <max.hsu@sifive.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
Message-id:
20210912130553.179501-5-frank.chang@sifive.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>