On 11/30/2017 02:53 PM, James Hogan wrote:
> On Tue, Nov 28, 2017 at 04:55:35PM -0800, David Daney wrote:
>> From: Carlos Munoz <[email protected]>
>>
>> Add a global resource manager to manage tagged pointers within
>> bootmem allocated memory. This is used by various functional
>> blocks in the Octeon core like the FPA, Ethernet nexus, etc.
>>
>> Signed-off-by: Carlos Munoz <[email protected]>
>> Signed-off-by: Steven J. Hill <[email protected]>
>> Signed-off-by: David Daney <[email protected]>
>> ---
>> arch/mips/cavium-octeon/Makefile | 3 +-
>> arch/mips/cavium-octeon/resource-mgr.c | 371 +++++++++++++++++++++++++++++++++
>> arch/mips/include/asm/octeon/octeon.h | 18 ++
>> 3 files changed, 391 insertions(+), 1 deletion(-)
>> create mode 100644 arch/mips/cavium-octeon/resource-mgr.c
>>
>> diff --git a/arch/mips/cavium-octeon/Makefile b/arch/mips/cavium-octeon/Makefile
>> index 7c02e542959a..0a299ab8719f 100644
>> --- a/arch/mips/cavium-octeon/Makefile
>> +++ b/arch/mips/cavium-octeon/Makefile
>> @@ -9,7 +9,8 @@
>> # Copyright (C) 2005-2009 Cavium Networks
>> #
>>
>> -obj-y := cpu.o setup.o octeon-platform.o octeon-irq.o csrc-octeon.o
>> +obj-y := cpu.o setup.o octeon-platform.o octeon-irq.o csrc-octeon.o \
>> + resource-mgr.o
>
> Maybe put that on a separate line like below.
OK
>
>> obj-y += dma-octeon.o
>> obj-y += octeon-memcpy.o
>> obj-y += executive/
>> diff --git a/arch/mips/cavium-octeon/resource-mgr.c b/arch/mips/cavium-octeon/resource-mgr.c
>> new file mode 100644
>> index 000000000000..ca25fa953402
>> --- /dev/null
>> +++ b/arch/mips/cavium-octeon/resource-mgr.c
>> @@ -0,0 +1,371 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Resource manager for Octeon.
>> + *
>> + * This file is subject to the terms and conditions of the GNU General Public
>> + * License. See the file "COPYING" in the main directory of this archive
>> + * for more details.
>> + *
>> + * Copyright (C) 2017 Cavium, Inc.
>> + */
>> +#include <linux/module.h>
>> +
>> +#include <asm/octeon/octeon.h>
>> +#include <asm/octeon/cvmx-bootmem.h>
>> +
>> +#define RESOURCE_MGR_BLOCK_NAME "cvmx-global-resources"
>> +#define MAX_RESOURCES 128
>> +#define INST_AVAILABLE -88
>> +#define OWNER 0xbadc0de
>> +
>> +struct global_resource_entry {
>> + struct global_resource_tag tag;
>> + u64 phys_addr;
>> + u64 size;
>> +};
>> +
>> +struct global_resources {
>> +#ifdef __LITTLE_ENDIAN_BITFIELD
>> + u32 rlock;
>> + u32 pad;
>> +#else
>> + u32 pad;
>> + u32 rlock;
>> +#endif
>> + u64 entry_cnt;
>> + struct global_resource_entry resource_entry[];
>> +};
>> +
>> +static struct global_resources *res_mgr_info;
>> +
>> +
>> +/*
>> + * The resource manager interacts with software running outside of the
>> + * Linux kernel, which necessitates locking to maintain data structure
>> + * consistency. These custom locking functions implement the locking
>> + * protocol, and cannot be replaced by kernel locking functions that
>> + * may use different in-memory structures.
>> + */
>> +
>> +static void res_mgr_lock(void)
>> +{
>> + unsigned int tmp;
>> + u64 lock = (u64)&res_mgr_info->rlock;
>
> presumably this could be a u32 *, avoid the cast to u64, and still work
> just fine below.
I will rewrite to just use cmpxchg()
>
>> +
>> + __asm__ __volatile__(
>> + ".set noreorder\n"
>> + "1: ll %[tmp], 0(%[addr])\n"
>> + " bnez %[tmp], 1b\n"
>> + " li %[tmp], 1\n"
>
> I believe the convention for .S files is for instructions in branch
> delay slots to be indented an additional space for readability. Maybe
> that would be worthwhile here.
>
>> + " sc %[tmp], 0(%[addr])\n"
>> + " beqz %[tmp], 1b\n"
>> + " nop\n"
>
> and here also.
>
>> + ".set reorder\n" :
>
> nit: strictly speaking there's no need for \n on the last line.
>
>> + [tmp] "=&r"(tmp) :
>> + [addr] "r"(lock) :
>> + "memory");
>
> minor style thing: its far more common to have : at the beginning of the
> line rather than the end.
>
>> +}
>> +
>> +static void res_mgr_unlock(void)
>> +{
>> + u64 lock = (u64)&res_mgr_info->rlock;
>
> same again
>
Will rewrite to use WRITE_ONCE().
>> +
>> + /* Wait until all resource operations finish before unlocking. */
>> + mb();
>> + __asm__ __volatile__(
>> + "sw $0, 0(%[addr])\n" : :
>> + [addr] "r"(lock) :
>> + "memory");
>> +
>> + /* Force a write buffer flush. */
>> + mb();
>> +}
>> +
>> +static int res_mgr_find_resource(struct global_resource_tag tag)
>> +{
>> + struct global_resource_entry *res_entry;
>> + int i;
>> +
>> + for (i = 0; i < res_mgr_info->entry_cnt; i++) {
>> + res_entry = &res_mgr_info->resource_entry[i];
>> + if (res_entry->tag.lo == tag.lo && res_entry->tag.hi == tag.hi)
>> + return i;
>> + }
>> + return -1;
>> +}
>> +
>> +/**
>> + * res_mgr_create_resource - Create a resource.
>> + * @tag: Identifies the resource.
>> + * @inst_cnt: Number of resource instances to create.
>> + *
>> + * Returns 0 if the source was created successfully.
>> + * Returns <0 for error codes.
>
> Only -1 seems to be returned. Is it worth returning some standard Linux
> error codes instead?
Yep. I fixed this and everything below for the next version of the
patch set.
Thanks,
David Daney
From 1585533421810621135@xxx Thu Nov 30 22:55:02 +0000 2017
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