Messages in this thread | | | Subject | Re: [PATCH v4 3/8] MIPS: Octeon: Add a global resource manager. | From | David Daney <> | Date | Thu, 30 Nov 2017 17:51:11 -0800 |
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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 <cmunoz@cavium.com> >> >> 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 <cmunoz@cavium.com> >> Signed-off-by: Steven J. Hill <Steven.Hill@cavium.com> >> Signed-off-by: David Daney <david.daney@cavium.com> >> --- >> 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
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