When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from. So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry. Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.
In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.
This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents. There's also a few places where I found we did not have a tag
and have introduced one.
Signed-off-by: Tom Rini <trini@konsulko.com>
Without the volatile attribute, compilers are entitled to optimize out
the same asm(). In the case of __udelay() in syscounter.c, it calls
`get_ticks()` twice, one for the starting time and the second in the
loop to check the current time. When compilers inline `get_ticks()`
they see the same `mrrc` instructions and optimize out the second one.
This leads to infinite loop since we don't get updated value from the
system counter.
Here is a portion of the disassembly of __udelay:
88: 428b cmp r3, r1
8a: f8ce 20a4 str.w r2, [lr, #164] ; 0xa4
8e: bf08 it eq
90: 4282 cmpeq r2, r0
92: f8ce 30a0 str.w r3, [lr, #160] ; 0xa0
96: d3f7 bcc.n 88 <__udelay+0x88>
98: e8bd 8cf0 ldmia.w sp!, {r4, r5, r6, r7, sl, fp, pc}
Note that final jump / loop at 96 to 88, we don't have any `mrrc`.
With a volatile attribute, the above changes to this:
8a: ec53 2f0e mrrc 15, 0, r2, r3, cr14
8e: 42ab cmp r3, r5
90: f8c1 20a4 str.w r2, [r1, #164] ; 0xa4
94: bf08 it eq
96: 42a2 cmpeq r2, r4
98: f8c1 30a0 str.w r3, [r1, #160] ; 0xa0
9c: d3f5 bcc.n 8a <__udelay+0x8a>
9e: e8bd 8cf0 ldmia.w sp!, {r4, r5, r6, r7, sl, fp, pc}
a2: bf00 nop
I'm advised[1] to put volatile on all asm(), so this commit also adds it
to the asm() in timer_init().
[1]: https://lists.denx.de/pipermail/u-boot/2018-March/322062.html
Signed-off-by: Yasushi SHOJI <yasushi.shoji@gmail.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Change is consistent with other SOCs and it is in preparation
for adding SOMs. SOC's related files are moved from cpu/ to
mach-imx/<SOC>.
This change is also coherent with the structure in kernel.
Signed-off-by: Stefano Babic <sbabic@denx.de>
CC: Fabio Estevam <fabio.estevam@nxp.com>
CC: Akshay Bhat <akshaybhat@timesys.com>
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CC: Hans de Goede <hdegoede@redhat.com>
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CC: Stephen Warren <swarren@nvidia.com>
CC: Andre Przywara <andre.przywara@arm.com>
CC: "Álvaro Fernández Rojas" <noltari@gmail.com>
CC: York Sun <york.sun@nxp.com>
CC: Xiaoliang Yang <xiaoliang.yang@nxp.com>
CC: Chen-Yu Tsai <wens@csie.org>
CC: George McCollister <george.mccollister@gmail.com>
CC: Sven Ebenfeld <sven.ebenfeld@gmail.com>
CC: Filip Brozovic <fbrozovic@gmail.com>
CC: Petr Kulhavy <brain@jikos.cz>
CC: Eric Nelson <eric@nelint.com>
CC: Bai Ping <ping.bai@nxp.com>
CC: Anson Huang <Anson.Huang@nxp.com>
CC: Sanchayan Maity <maitysanchayan@gmail.com>
CC: Lokesh Vutla <lokeshvutla@ti.com>
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Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
