[PATCH v2 2/6] mtd: spi-nor: add erase die (chip) capability

[Fabio Estevam]

On 03/11/2023 09:30, Fabio Estevam wrote:

> The problem I see is that the erase operation was super slow.
> 
> Please see the timestamps to get an idea.
> 
> Is this slow-erase behavior expected? Please note that the
> SPI controller on the i.MX8MP does not have DMA support at the moment.

Measuring the time it takes to erase the whole flash:

root at mcde3000a:~# time flash_erase /dev/mtd0 0 0
Erasing 131072 Kibyte @ 0 --  0 [ 1502.857687] spi-nor spi0.0: ***** 
nor->reg_proto = 0x00010101
% complete [ 1502.866354] spi-nor spi0.0: *****
[ 1502.870631] spi-nor spi0.0: ***** op.cmd.nbytes = 0x01
[ 1502.875891] spi-nor spi0.0: ***** op.cmd.buswidth = 0x01
[ 1502.881311] spi-nor spi0.0: ***** op.cmd.opcode = 0xc4
[ 1502.886559] spi-nor spi0.0: *****
[ 1502.889888] spi-nor spi0.0: ***** op.addr.nbytes = 0x04
[ 1502.895220] spi-nor spi0.0: ***** op.addr.buswidth = 0x01
[ 1502.900724] spi-nor spi0.0: ***** op.addr.buswidth = 0x0
[ 1502.906141] spi-nor spi0.0: *****
[ 1502.909474] spi-nor spi0.0: ***** op.dummy.nbytes = 0x00
[ 1502.914899] spi-nor spi0.0: ***** op.dummy.buswidth = 0x00
[ 1502.920489] spi-nor spi0.0: *****
[ 1502.923823] spi-nor spi0.0: ***** op.data.buswidth = 0x00
[ 1502.929323] spi-nor spi0.0: ***** op.data.nbytes = 0
[ 1620.329673] spi-nor spi0.0: ***** nor->reg_proto = 0x00010101
[ 1620.335538] spi-nor spi0.0: *****
[ 1620.338869] spi-nor spi0.0: ***** op.cmd.nbytes = 0x01
[ 1620.344127] spi-nor spi0.0: ***** op.cmd.buswidth = 0x01
[ 1620.349543] spi-nor spi0.0: ***** op.cmd.opcode = 0xc4
[ 1620.354791] spi-nor spi0.0: *****
[ 1620.358123] spi-nor spi0.0: ***** op.addr.nbytes = 0x04
[ 1620.363452] spi-nor spi0.0: ***** op.addr.buswidth = 0x01
[ 1620.368953] spi-nor spi0.0: ***** op.addr.buswidth = 0x4000000
[ 1620.374890] spi-nor spi0.0: *****
[ 1620.378229] spi-nor spi0.0: ***** op.dummy.nbytes = 0x00
[ 1620.383646] spi-nor spi0.0: ***** op.dummy.buswidth = 0x00
[ 1620.389234] spi-nor spi0.0: *****
[ 1620.392566] spi-nor spi0.0: ***** op.data.buswidth = 0x00
[ 1620.398068] spi-nor spi0.0: ***** op.data.nbytes = 0
Erasing 131072 Kibyte @ 0 -- 100 % complete

real	3m56.795s
user	0m0.001s
sys	3m15.840s

Originally, I was also getting around 4 minutes to erase the whole 
flash,
so the erase-die performance is comparable to the erase one sector at 
time.