Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH v2] firmware: smccc: Add ARCH_SOC_ID support | From | Steven Price <> | Date | Wed, 17 Jun 2020 14:34:41 +0100 |
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On 17/06/2020 11:05, Sudeep Holla wrote: > SMCCC v1.2 adds a new optional function SMCCC_ARCH_SOC_ID to obtain a > SiP defined SoC identification value. Add support for the same. > > Also using the SoC bus infrastructure, let us expose the platform > specific SoC atrributes under sysfs. > > There are various ways in which it can be represented in shortened form > for efficiency and ease of parsing for userspace. The chosen form is > described in the ABI document. > > Cc: Steven Price <steven.price@arm.com> > Cc: Etienne Carriere <etienne.carriere@st.com> > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > --- > Documentation/ABI/testing/sysfs-devices-soc | 30 ++++++ > drivers/firmware/smccc/Kconfig | 9 ++ > drivers/firmware/smccc/Makefile | 1 + > drivers/firmware/smccc/soc_id.c | 114 ++++++++++++++++++++ > include/linux/arm-smccc.h | 5 + > 5 files changed, 159 insertions(+) > create mode 100644 drivers/firmware/smccc/soc_id.c > > Changes from v1[1] -> v2: > - Dropped new jep106_id added to SoC infrastructure > - Dropped all the tags(acks/reviews) as there is change in the format > - Updated the format for SoC id to ensure there will be no > conflict in the namespace > > [1] https://lore.kernel.org/lkml/20200522124951.35776-1-sudeep.holla@arm.com/ > > diff --git a/Documentation/ABI/testing/sysfs-devices-soc b/Documentation/ABI/testing/sysfs-devices-soc > index ba3a3fac0ee1..50707f316ea9 100644 > --- a/Documentation/ABI/testing/sysfs-devices-soc > +++ b/Documentation/ABI/testing/sysfs-devices-soc > @@ -26,6 +26,30 @@ contact: Lee Jones <lee.jones@linaro.org> > Read-only attribute common to all SoCs. Contains SoC family name > (e.g. DB8500). > > + On many of ARM based silicon with SMCCC v1.2+ compliant firmware > + this will contain the JEDEC JEP106 manufacturer’s identification > + code. The format is "jep106:XXYY" where XX is identity code and > + YY is continuation code. > + > + This manufacturer’s identification code is defined by one > + or more eight (8) bit fields, each consisting of seven (7) > + data bits plus one (1) odd parity bit. It is a single field, > + limiting the possible number of vendors to 126. To expand > + the maximum number of identification codes, a continuation > + scheme has been defined. > + > + The specified mechanism is that an identity code of 0x7F > + represents the "continuation code" and implies the presence > + of an additional identity code field, and this mechanism > + may be extended to multiple continuation codes followed > + by the manufacturer's identity code. > + > + For example, ARM has identity code 0x7F 0x7F 0x7F 0x7F 0x3B, > + which is code 0x3B on the fifth 'page'. This can be shortened
NIT: s/can be/is/ - since the format always uses the short form.
> + as JEP106 identity code of 0x3B and a continuation code of > + 0x4 to represent the four continuation codes preceding the > + identity code. > + > What: /sys/devices/socX/serial_number > Date: January 2019 > contact: Bjorn Andersson <bjorn.andersson@linaro.org> > @@ -40,6 +64,12 @@ contact: Lee Jones <lee.jones@linaro.org> > Read-only attribute supported by most SoCs. In the case of > ST-Ericsson's chips this contains the SoC serial number. > > + On many of ARM based silicon with SMCCC v1.2+ compliant firmware > + this will contain the SOC ID appended to the family attribute > + to ensure there is no clash in this namespace across various > + vendors. The format is "jep106:XXYY:ZZZZ" where XX is identity > + code, YY is continuation code and ZZZZ is the SOC ID. > + > What: /sys/devices/socX/revision > Date: January 2012 > contact: Lee Jones <lee.jones@linaro.org> > diff --git a/drivers/firmware/smccc/Kconfig b/drivers/firmware/smccc/Kconfig > index 27b675d76235..15e7466179a6 100644 > --- a/drivers/firmware/smccc/Kconfig > +++ b/drivers/firmware/smccc/Kconfig > @@ -14,3 +14,12 @@ config HAVE_ARM_SMCCC_DISCOVERY > to add SMCCC discovery mechanism though the PSCI firmware > implementation of PSCI_FEATURES(SMCCC_VERSION) which returns > success on firmware compliant to SMCCC v1.1 and above. > + > +config ARM_SMCCC_SOC_ID > + bool "SoC bus device for the ARM SMCCC SOC_ID" > + depends on HAVE_ARM_SMCCC_DISCOVERY > + default y > + select SOC_BUS > + help > + Include support for the SoC bus on the ARM SMCCC firmware based > + platforms providing some sysfs information about the SoC variant. > diff --git a/drivers/firmware/smccc/Makefile b/drivers/firmware/smccc/Makefile > index 6f369fe3f0b9..72ab84042832 100644 > --- a/drivers/firmware/smccc/Makefile > +++ b/drivers/firmware/smccc/Makefile > @@ -1,3 +1,4 @@ > # SPDX-License-Identifier: GPL-2.0 > # > obj-$(CONFIG_HAVE_ARM_SMCCC_DISCOVERY) += smccc.o > +obj-$(CONFIG_ARM_SMCCC_SOC_ID) += soc_id.o > diff --git a/drivers/firmware/smccc/soc_id.c b/drivers/firmware/smccc/soc_id.c > new file mode 100644 > index 000000000000..cf6888fd84aa > --- /dev/null > +++ b/drivers/firmware/smccc/soc_id.c > @@ -0,0 +1,114 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright 2020 Arm Limited > + */ > + > +#define pr_fmt(fmt) "SMCCC: SOC_ID: " fmt > + > +#include <linux/arm-smccc.h> > +#include <linux/bitfield.h> > +#include <linux/device.h> > +#include <linux/module.h> > +#include <linux/kernel.h> > +#include <linux/slab.h> > +#include <linux/sys_soc.h> > + > +#define SMCCC_SOC_ID_JEP106_BANK_IDX_MASK GENMASK(30, 24) > +/* > + * As per the SMC Calling Convention specification v1.2 (ARM DEN 0028C) > + * Section 7.4 SMCCC_ARCH_SOC_ID bits[23:16] are JEP-106 identification > + * code with parity bit for the SiP. We can drop the parity bit. > + */ > +#define SMCCC_SOC_ID_JEP106_ID_CODE_MASK GENMASK(22, 16) > +#define SMCCC_SOC_ID_IMP_DEF_SOC_ID_MASK GENMASK(15, 0) > + > +#define JEP106_BANK_CONT_CODE(x) \ > + (u8)(FIELD_GET(SMCCC_SOC_ID_JEP106_BANK_IDX_MASK, (x))) > +#define JEP106_ID_CODE(x) \ > + (u8)(FIELD_GET(SMCCC_SOC_ID_JEP106_ID_CODE_MASK, (x))) > +#define IMP_DEF_SOC_ID(x) \ > + (u16)(FIELD_GET(SMCCC_SOC_ID_IMP_DEF_SOC_ID_MASK, (x))) > + > +static struct soc_device *soc_dev; > +static struct soc_device_attribute *soc_dev_attr; > + > +static int __init smccc_soc_init(void) > +{ > + struct arm_smccc_res res; > + int soc_id_rev, soc_id_version; > + static char soc_id_str[16], soc_id_rev_str[12]; > + static char soc_id_jep106_id_str[12]; > + > + if (arm_smccc_get_version() < ARM_SMCCC_VERSION_1_2) > + return 0; > + > + if (arm_smccc_1_1_get_conduit() == SMCCC_CONDUIT_NONE) { > + pr_err("%s: invalid SMCCC conduit\n", __func__); > + return -EOPNOTSUPP; > + } > + > + arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, > + ARM_SMCCC_ARCH_SOC_ID, &res); > + > + if (res.a0 == SMCCC_RET_NOT_SUPPORTED) { > + pr_info("ARCH_SOC_ID not implemented, skipping ....\n"); > + return 0; > + } > + > + if ((int)res.a0 < 0) { > + pr_info("ARCH_FEATURES(ARCH_SOC_ID) returned error: %lx\n", > + res.a0); > + return -EINVAL; > + } > + > + arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 0, &res); > + if ((int)res.a0 < 0) { > + pr_err("ARCH_SOC_ID(0) returned error: %lx\n", res.a0); > + return -EINVAL; > + } > + > + soc_id_version = res.a0; > + > + arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 1, &res); > + if ((int)res.a0 < 0) { > + pr_err("ARCH_SOC_ID(1) returned error: %lx\n", res.a0); > + return -EINVAL; > + } > + > + soc_id_rev = res.a0; > + > + soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL); > + if (!soc_dev_attr) > + return -ENOMEM; > + > + sprintf(soc_id_rev_str, "0x%08x", soc_id_rev); > + sprintf(soc_id_jep106_id_str, "jep106:%02x%02x", > + JEP106_BANK_CONT_CODE(soc_id_version), > + JEP106_ID_CODE(soc_id_version)); > + sprintf(soc_id_str, "%s:%04x", soc_id_jep106_id_str, > + IMP_DEF_SOC_ID(soc_id_version));
My maths might be wrong, but I think this is one byte too long:
soc_id_jep106_id_str can be 11 characters (without the NUL), then we have a ':' byte followed by 4 hex digits and a trailing NUL: 11 + 1 + 4 + 1 = 17, but the char array is 16 bytes long.
With that fixed feel free to add my "Reviewed-by".
Steve
> + > + soc_dev_attr->soc_id = soc_id_str; > + soc_dev_attr->revision = soc_id_rev_str; > + soc_dev_attr->family = soc_id_jep106_id_str; > + > + soc_dev = soc_device_register(soc_dev_attr); > + if (IS_ERR(soc_dev)) { > + kfree(soc_dev_attr); > + return PTR_ERR(soc_dev); > + } > + > + pr_info("ID = %s Revision = %s\n", soc_dev_attr->soc_id, > + soc_dev_attr->revision); > + > + return 0; > +} > +module_init(smccc_soc_init); > + > +static void __exit smccc_soc_exit(void) > +{ > + if (soc_dev) > + soc_device_unregister(soc_dev); > + kfree(soc_dev_attr); > +} > +module_exit(smccc_soc_exit); > diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h > index 56d6a5c6e353..8254e11ea857 100644 > --- a/include/linux/arm-smccc.h > +++ b/include/linux/arm-smccc.h > @@ -71,6 +71,11 @@ > ARM_SMCCC_SMC_32, \ > 0, 1) > > +#define ARM_SMCCC_ARCH_SOC_ID \ > + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ > + ARM_SMCCC_SMC_32, \ > + 0, 2) > + > #define ARM_SMCCC_ARCH_WORKAROUND_1 \ > ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ > ARM_SMCCC_SMC_32, \ >
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