| Message ID | 20240329000822.3363568-4-volodymyr_babchuk@epam.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Add experimental support for Qualcomm SA8155P SoC | expand |
Hello, On 29/03/2024 01:08, Volodymyr Babchuk wrote: > > > Qualcomm SA8155P is the automotive variant of SM8150 aka Snapdragon > 855. > > This patch adds very basic support for the platform. We need to handle > Qualcomm-specific SMC to workaround quirk in the QCOM SCM driver in > the Linux kernel. Basically the driver tries multiple different SMCs > to determine which calling convention is supported by a SoC. If all > calls fail it decides that the SoC uses "legacy SMC" and tries to > communicate with SCM by issuing SMC with funcid = 1. Problem is that > Xen has own understanding on how such SMC should be handled. It > interprets this SMC as legacy PSCI_cpu_off and happily turns of Linux > boot CPU. > > To workaround this, we pretend that we support > QCOM_SCM_INFO_IS_CALL_AVAIL, this will make the driver use the latest > calling convention. All subsequent calls will fail anyways and the > driver will terminate self gracefully. This is not a big deal, because > right now (with Linux 6.8) even on baremetal setup the driver fails > anyways, because it does not know how to work with this SoC. Therefore I would consider adding a Kconfig option and placing it under experimental > > Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com> > --- > xen/arch/arm/platforms/Makefile | 1 + > xen/arch/arm/platforms/qcom.c | 77 +++++++++++++++++++++++++++++++++ > 2 files changed, 78 insertions(+) > create mode 100644 xen/arch/arm/platforms/qcom.c > > diff --git a/xen/arch/arm/platforms/Makefile b/xen/arch/arm/platforms/Makefile > index 8632f4115f..6873735ef0 100644 > --- a/xen/arch/arm/platforms/Makefile > +++ b/xen/arch/arm/platforms/Makefile > @@ -9,5 +9,6 @@ obj-$(CONFIG_ALL_PLAT) += sunxi.o > obj-$(CONFIG_ALL64_PLAT) += thunderx.o > obj-$(CONFIG_ALL64_PLAT) += xgene-storm.o > obj-$(CONFIG_ALL64_PLAT) += brcm-raspberry-pi.o > +obj-$(CONFIG_ALL64_PLAT) += qcom.o > obj-$(CONFIG_MPSOC_PLATFORM) += xilinx-zynqmp.o > obj-$(CONFIG_MPSOC_PLATFORM) += xilinx-zynqmp-eemi.o > diff --git a/xen/arch/arm/platforms/qcom.c b/xen/arch/arm/platforms/qcom.c > new file mode 100644 > index 0000000000..77e9c58649 > --- /dev/null > +++ b/xen/arch/arm/platforms/qcom.c > @@ -0,0 +1,77 @@ > +/* > + * xen/arch/arm/platforms/qcom.c > + * > + * Qualcomm SoCs specific code > + * > + * Volodymyr Babchuk <volodymyr_babchuk@epam.com> > + * > + * Copyright (c) 2024 EPAM Systems. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. Please use SPDX identifier instead of license text > + */ > + > +#include <asm/platform.h> > +#include <public/arch-arm/smccc.h> no need for this public header > +#include <asm/smccc.h> > + > +#define SCM_SMC_FNID(s, c) ((((s) & 0xFF) << 8) | ((c) & 0xFF)) spaces instead of tabs > +#define QCOM_SCM_SVC_INFO 0x06 spaces instead of tabs > +#define QCOM_SCM_INFO_IS_CALL_AVAIL 0x01 > + > +#define ARM_SMCCC_SIP_QCOM_SCM_IS_CALL_AVAIL \ > + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ > + ARM_SMCCC_CONV_64, \ > + ARM_SMCCC_OWNER_SIP, \ > + SCM_SMC_FNID(QCOM_SCM_SVC_INFO, \ > + QCOM_SCM_INFO_IS_CALL_AVAIL)) > + > +static const char * const sa8155p_dt_compat[] __initconst = > +{ > + "qcom,sa8155p", > + NULL > +}; > + > +static bool sa8155p_smc(struct cpu_user_regs *regs) > +{ > + uint32_t funcid = get_user_reg(regs, 0); > + > + switch ( funcid ) { brace should be placed on a new line ~Michal
Hi Volodymyr, On 29/03/2024 00:08, Volodymyr Babchuk wrote: > Qualcomm SA8155P is the automotive variant of SM8150 aka Snapdragon > 855. > > This patch adds very basic support for the platform. We need to handle > Qualcomm-specific SMC to workaround quirk in the QCOM SCM driver in > the Linux kernel. Basically the driver tries multiple different SMCs > to determine which calling convention is supported by a SoC. If all > calls fail it decides that the SoC uses "legacy SMC" and tries to > communicate with SCM by issuing SMC with funcid = 1. Problem is that > Xen has own understanding on how such SMC should be handled. It > interprets this SMC as legacy PSCI_cpu_off and happily turns of Linux > boot CPU. > > To workaround this, we pretend that we support > QCOM_SCM_INFO_IS_CALL_AVAIL, this will make the driver use the latest > calling convention. All subsequent calls will fail anyways and the > driver will terminate self gracefully. This is not a big deal, because > right now (with Linux 6.8) even on baremetal setup the driver fails > anyways, because it does not know how to work with this SoC. Is there any patches that are not yet merged and/or on a Qualcomm specific tree? I just want to make sure that we have a code that will still work in the near future. > > Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com> > --- > xen/arch/arm/platforms/Makefile | 1 + > xen/arch/arm/platforms/qcom.c | 77 +++++++++++++++++++++++++++++++++ > 2 files changed, 78 insertions(+) > create mode 100644 xen/arch/arm/platforms/qcom.c > > diff --git a/xen/arch/arm/platforms/Makefile b/xen/arch/arm/platforms/Makefile > index 8632f4115f..6873735ef0 100644 > --- a/xen/arch/arm/platforms/Makefile > +++ b/xen/arch/arm/platforms/Makefile > @@ -9,5 +9,6 @@ obj-$(CONFIG_ALL_PLAT) += sunxi.o > obj-$(CONFIG_ALL64_PLAT) += thunderx.o > obj-$(CONFIG_ALL64_PLAT) += xgene-storm.o > obj-$(CONFIG_ALL64_PLAT) += brcm-raspberry-pi.o > +obj-$(CONFIG_ALL64_PLAT) += qcom.o > obj-$(CONFIG_MPSOC_PLATFORM) += xilinx-zynqmp.o > obj-$(CONFIG_MPSOC_PLATFORM) += xilinx-zynqmp-eemi.o > diff --git a/xen/arch/arm/platforms/qcom.c b/xen/arch/arm/platforms/qcom.c > new file mode 100644 > index 0000000000..77e9c58649 > --- /dev/null > +++ b/xen/arch/arm/platforms/qcom.c > @@ -0,0 +1,77 @@ > +/* > + * xen/arch/arm/platforms/qcom.c > + * > + * Qualcomm SoCs specific code > + * > + * Volodymyr Babchuk <volodymyr_babchuk@epam.com> > + * > + * Copyright (c) 2024 EPAM Systems. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. Did you intend to license the code as GPLv2+? See [1], for some context. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include <asm/platform.h> > +#include <public/arch-arm/smccc.h> > +#include <asm/smccc.h> > + > +#define SCM_SMC_FNID(s, c) ((((s) & 0xFF) << 8) | ((c) & 0xFF)) > +#define QCOM_SCM_SVC_INFO 0x06 > +#define QCOM_SCM_INFO_IS_CALL_AVAIL 0x01 > + > +#define ARM_SMCCC_SIP_QCOM_SCM_IS_CALL_AVAIL \ I find this name a little bit too long. Can we remove ARM_SMCCC as I don't think it adds any value? > + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ > + ARM_SMCCC_CONV_64, \ > + ARM_SMCCC_OWNER_SIP, \ > + SCM_SMC_FNID(QCOM_SCM_SVC_INFO, \ > + QCOM_SCM_INFO_IS_CALL_AVAIL)) > + > +static const char * const sa8155p_dt_compat[] __initconst = > +{ > + "qcom,sa8155p", > + NULL > +}; > + > +static bool sa8155p_smc(struct cpu_user_regs *regs) > +{ > + uint32_t funcid = get_user_reg(regs, 0); > + The function will also called for guests. But only the hardware domain/dom0 is using the machine qcom,sa8155p, so I think you want to check the domain. > + switch ( funcid ) { > + case ARM_SMCCC_SIP_QCOM_SCM_IS_CALL_AVAIL: > + /* > + * We need to implement this specific call only to make Linux > + * counterpart happy: QCOM SCM driver in Linux tries to > + * determine calling convention by issuing this particular > + * SMC. If it receives an error it assumes that platform uses > + * legacy calling convention and tries to issue SMC with > + * funcid = 1. Xen interprets this as PSCI_cpu_off and turns > + * off Linux boot vCPU. > + */ > + set_user_reg(regs, 0, ARM_SMCCC_SUCCESS); > + set_user_reg(regs, 1, 1); > + return true; > + default: > + return false; > + } > +} > + > +PLATFORM_START(sa8155p, "Qualcomm SA8155P") > + .compatible = sa8155p_dt_compat, > + .smc = sa8155p_smc > +PLATFORM_END > + > +/* > + * Local variables: > + * mode: C > + * c-file-style: "BSD" > + * c-basic-offset: 4 > + * indent-tabs-mode: nil > + * End: > + */ Cheers, [1] https://lore.kernel.org/1272bb77-8a93-4ca2-af0d-4c1c36729307@xen.org
diff --git a/xen/arch/arm/platforms/Makefile b/xen/arch/arm/platforms/Makefile index 8632f4115f..6873735ef0 100644 --- a/xen/arch/arm/platforms/Makefile +++ b/xen/arch/arm/platforms/Makefile @@ -9,5 +9,6 @@ obj-$(CONFIG_ALL_PLAT) += sunxi.o obj-$(CONFIG_ALL64_PLAT) += thunderx.o obj-$(CONFIG_ALL64_PLAT) += xgene-storm.o obj-$(CONFIG_ALL64_PLAT) += brcm-raspberry-pi.o +obj-$(CONFIG_ALL64_PLAT) += qcom.o obj-$(CONFIG_MPSOC_PLATFORM) += xilinx-zynqmp.o obj-$(CONFIG_MPSOC_PLATFORM) += xilinx-zynqmp-eemi.o diff --git a/xen/arch/arm/platforms/qcom.c b/xen/arch/arm/platforms/qcom.c new file mode 100644 index 0000000000..77e9c58649 --- /dev/null +++ b/xen/arch/arm/platforms/qcom.c @@ -0,0 +1,77 @@ +/* + * xen/arch/arm/platforms/qcom.c + * + * Qualcomm SoCs specific code + * + * Volodymyr Babchuk <volodymyr_babchuk@epam.com> + * + * Copyright (c) 2024 EPAM Systems. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <asm/platform.h> +#include <public/arch-arm/smccc.h> +#include <asm/smccc.h> + +#define SCM_SMC_FNID(s, c) ((((s) & 0xFF) << 8) | ((c) & 0xFF)) +#define QCOM_SCM_SVC_INFO 0x06 +#define QCOM_SCM_INFO_IS_CALL_AVAIL 0x01 + +#define ARM_SMCCC_SIP_QCOM_SCM_IS_CALL_AVAIL \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_CONV_64, \ + ARM_SMCCC_OWNER_SIP, \ + SCM_SMC_FNID(QCOM_SCM_SVC_INFO, \ + QCOM_SCM_INFO_IS_CALL_AVAIL)) + +static const char * const sa8155p_dt_compat[] __initconst = +{ + "qcom,sa8155p", + NULL +}; + +static bool sa8155p_smc(struct cpu_user_regs *regs) +{ + uint32_t funcid = get_user_reg(regs, 0); + + switch ( funcid ) { + case ARM_SMCCC_SIP_QCOM_SCM_IS_CALL_AVAIL: + /* + * We need to implement this specific call only to make Linux + * counterpart happy: QCOM SCM driver in Linux tries to + * determine calling convention by issuing this particular + * SMC. If it receives an error it assumes that platform uses + * legacy calling convention and tries to issue SMC with + * funcid = 1. Xen interprets this as PSCI_cpu_off and turns + * off Linux boot vCPU. + */ + set_user_reg(regs, 0, ARM_SMCCC_SUCCESS); + set_user_reg(regs, 1, 1); + return true; + default: + return false; + } +} + +PLATFORM_START(sa8155p, "Qualcomm SA8155P") + .compatible = sa8155p_dt_compat, + .smc = sa8155p_smc +PLATFORM_END + +/* + * Local variables: + * mode: C + * c-file-style: "BSD" + * c-basic-offset: 4 + * indent-tabs-mode: nil + * End: + */
Qualcomm SA8155P is the automotive variant of SM8150 aka Snapdragon 855. This patch adds very basic support for the platform. We need to handle Qualcomm-specific SMC to workaround quirk in the QCOM SCM driver in the Linux kernel. Basically the driver tries multiple different SMCs to determine which calling convention is supported by a SoC. If all calls fail it decides that the SoC uses "legacy SMC" and tries to communicate with SCM by issuing SMC with funcid = 1. Problem is that Xen has own understanding on how such SMC should be handled. It interprets this SMC as legacy PSCI_cpu_off and happily turns of Linux boot CPU. To workaround this, we pretend that we support QCOM_SCM_INFO_IS_CALL_AVAIL, this will make the driver use the latest calling convention. All subsequent calls will fail anyways and the driver will terminate self gracefully. This is not a big deal, because right now (with Linux 6.8) even on baremetal setup the driver fails anyways, because it does not know how to work with this SoC. Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com> --- xen/arch/arm/platforms/Makefile | 1 + xen/arch/arm/platforms/qcom.c | 77 +++++++++++++++++++++++++++++++++ 2 files changed, 78 insertions(+) create mode 100644 xen/arch/arm/platforms/qcom.c