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firmware: qcom_scm: Dynamically support SMCCC and legacy conventions
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Dynamically support SMCCCC and legacy conventions by detecting which
convention to use at runtime. qcom_scm_call_atomic and qcom_scm_call can
then be moved in qcom_scm.c and use underlying convention backend as
appropriate. Thus, rename qcom_scm-64,-32 to reflect that they are
backends for -smc and -legacy, respectively.

Also add support for making SCM calls earlier than when SCM driver
probes to support use cases such as qcom_scm_set_cold_boot_addr. Support
is added by lazily initializing the convention and guarding the query
with a spin lock.  The limitation of these early SCM calls is that they
cannot use DMA, as in the case of >4 arguments for SMC convention and
any non-atomic call for legacy convention.

Tested-by: Brian Masney <masneyb@onstation.org> # arm32
Tested-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Elliot Berman <eberman@codeaurora.org>
Link: https://lore.kernel.org/r/1578431066-19600-18-git-send-email-eberman@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
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Elliot Berman authored and Bjorn Andersson committed Jan 8, 2020
1 parent 57d3b81 commit 9a434ce
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Showing 6 changed files with 176 additions and 135 deletions.
8 changes: 0 additions & 8 deletions drivers/firmware/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -239,14 +239,6 @@ config QCOM_SCM
depends on ARM || ARM64
select RESET_CONTROLLER

config QCOM_SCM_32
def_bool y
depends on QCOM_SCM && ARM

config QCOM_SCM_64
def_bool y
depends on QCOM_SCM && ARM64

config QCOM_SCM_DOWNLOAD_MODE_DEFAULT
bool "Qualcomm download mode enabled by default"
depends on QCOM_SCM
Expand Down
4 changes: 1 addition & 3 deletions drivers/firmware/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -17,9 +17,7 @@ obj-$(CONFIG_ISCSI_IBFT) += iscsi_ibft.o
obj-$(CONFIG_FIRMWARE_MEMMAP) += memmap.o
obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o
obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o
obj-$(CONFIG_QCOM_SCM) += qcom_scm.o
obj-$(CONFIG_QCOM_SCM_64) += qcom_scm-64.o
obj-$(CONFIG_QCOM_SCM_32) += qcom_scm-32.o
obj-$(CONFIG_QCOM_SCM) += qcom_scm.o qcom_scm-smc.o qcom_scm-legacy.o
obj-$(CONFIG_TI_SCI_PROTOCOL) += ti_sci.o
obj-$(CONFIG_TRUSTED_FOUNDATIONS) += trusted_foundations.o
obj-$(CONFIG_TURRIS_MOX_RWTM) += turris-mox-rwtm.o
Expand Down
31 changes: 5 additions & 26 deletions drivers/firmware/qcom_scm-32.c → drivers/firmware/qcom_scm-legacy.c
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,6 @@ struct arm_smccc_args {
unsigned long args[8];
};

#define SCM_LEGACY_FNID(s, c) (((s) << 10) | ((c) & 0x3ff))

/**
* struct scm_legacy_command - one SCM command buffer
Expand Down Expand Up @@ -129,8 +128,8 @@ static void __scm_legacy_do(const struct arm_smccc_args *smc,
* and response buffers is taken care of by qcom_scm_call; however, callers are
* responsible for any other cached buffers passed over to the secure world.
*/
int qcom_scm_call(struct device *dev, const struct qcom_scm_desc *desc,
struct qcom_scm_res *res)
int scm_legacy_call(struct device *dev, const struct qcom_scm_desc *desc,
struct qcom_scm_res *res)
{
u8 arglen = desc->arginfo & 0xf;
int ret = 0, context_id;
Expand Down Expand Up @@ -218,9 +217,9 @@ int qcom_scm_call(struct device *dev, const struct qcom_scm_desc *desc,
* This shall only be used with commands that are guaranteed to be
* uninterruptable, atomic and SMP safe.
*/
int qcom_scm_call_atomic(struct device *unused,
const struct qcom_scm_desc *desc,
struct qcom_scm_res *res)
int scm_legacy_call_atomic(struct device *unused,
const struct qcom_scm_desc *desc,
struct qcom_scm_res *res)
{
int context_id;
struct arm_smccc_res smc_res;
Expand All @@ -241,23 +240,3 @@ int qcom_scm_call_atomic(struct device *unused,

return smc_res.a0;
}

int __qcom_scm_is_call_available(struct device *dev, u32 svc_id, u32 cmd_id)
{
int ret;
struct qcom_scm_desc desc = {
.svc = QCOM_SCM_SVC_INFO,
.cmd = QCOM_SCM_INFO_IS_CALL_AVAIL,
.args[0] = SCM_LEGACY_FNID(svc_id, cmd_id),
.arginfo = QCOM_SCM_ARGS(1),
};
struct qcom_scm_res res;

ret = qcom_scm_call(dev, &desc, &res);

return ret ? : res.result[0];
}

void __qcom_scm_init(void)
{
}
95 changes: 5 additions & 90 deletions drivers/firmware/qcom_scm-64.c → drivers/firmware/qcom_scm-smc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,8 +14,6 @@

#include "qcom_scm.h"

#define SCM_SMC_FNID(s, c) ((((s) & 0xFF) << 8) | ((c) & 0xFF))

/**
* struct arm_smccc_args
* @args: The array of values used in registers in smc instruction
Expand All @@ -24,7 +22,6 @@ struct arm_smccc_args {
unsigned long args[8];
};

static u64 qcom_smccc_convention = -1;
static DEFINE_MUTEX(qcom_scm_lock);

#define QCOM_SCM_EBUSY_WAIT_MS 30
Expand Down Expand Up @@ -80,8 +77,8 @@ static void __scm_smc_do(const struct arm_smccc_args *smc,
} while (res->a0 == QCOM_SCM_V2_EBUSY);
}

static int __scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
struct qcom_scm_res *res, bool atomic)
int scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
struct qcom_scm_res *res, bool atomic)
{
int arglen = desc->arginfo & 0xf;
int i;
Expand All @@ -90,6 +87,9 @@ static int __scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
size_t alloc_len;
gfp_t flag = atomic ? GFP_ATOMIC : GFP_KERNEL;
u32 smccc_call_type = atomic ? ARM_SMCCC_FAST_CALL : ARM_SMCCC_STD_CALL;
u32 qcom_smccc_convention =
(qcom_scm_convention == SMC_CONVENTION_ARM_32) ?
ARM_SMCCC_SMC_32 : ARM_SMCCC_SMC_64;
struct arm_smccc_res smc_res;
struct arm_smccc_args smc = {0};

Expand Down Expand Up @@ -149,88 +149,3 @@ static int __scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,

return (long)smc_res.a0 ? qcom_scm_remap_error(smc_res.a0) : 0;
}

/**
* qcom_scm_call() - Invoke a syscall in the secure world
* @dev: device
* @svc_id: service identifier
* @cmd_id: command identifier
* @desc: Descriptor structure containing arguments and return values
*
* Sends a command to the SCM and waits for the command to finish processing.
* This should *only* be called in pre-emptible context.
*/
int qcom_scm_call(struct device *dev, const struct qcom_scm_desc *desc,
struct qcom_scm_res *res)
{
might_sleep();
return __scm_smc_call(dev, desc, res, false);
}

/**
* qcom_scm_call_atomic() - atomic variation of qcom_scm_call()
* @dev: device
* @svc_id: service identifier
* @cmd_id: command identifier
* @desc: Descriptor structure containing arguments and return values
* @res: Structure containing results from SMC/HVC call
*
* Sends a command to the SCM and waits for the command to finish processing.
* This can be called in atomic context.
*/
int qcom_scm_call_atomic(struct device *dev, const struct qcom_scm_desc *desc,
struct qcom_scm_res *res)
{
return __scm_smc_call(dev, desc, res, true);
}

int __qcom_scm_is_call_available(struct device *dev, u32 svc_id, u32 cmd_id)
{
int ret;
struct qcom_scm_desc desc = {
.svc = QCOM_SCM_SVC_INFO,
.cmd = QCOM_SCM_INFO_IS_CALL_AVAIL,
.owner = ARM_SMCCC_OWNER_SIP,
};
struct qcom_scm_res res;

desc.arginfo = QCOM_SCM_ARGS(1);
desc.args[0] = SCM_SMC_FNID(svc_id, cmd_id) |
(ARM_SMCCC_OWNER_SIP << ARM_SMCCC_OWNER_SHIFT);

ret = qcom_scm_call(dev, &desc, &res);

return ret ? : res.result[0];
}

void __qcom_scm_init(void)
{
struct qcom_scm_desc desc = {
.svc = QCOM_SCM_SVC_INFO,
.cmd = QCOM_SCM_INFO_IS_CALL_AVAIL,
.args[0] = SCM_SMC_FNID(QCOM_SCM_SVC_INFO,
QCOM_SCM_INFO_IS_CALL_AVAIL) |
(ARM_SMCCC_OWNER_SIP << ARM_SMCCC_OWNER_SHIFT),
.arginfo = QCOM_SCM_ARGS(1),
.owner = ARM_SMCCC_OWNER_SIP,
};
struct qcom_scm_res res;
int ret;

qcom_smccc_convention = ARM_SMCCC_SMC_64;
// Device isn't required as there is only one argument - no device
// needed to dma_map_single to secure world
ret = qcom_scm_call_atomic(NULL, &desc, &res);
if (!ret && res.result[0] == 1)
goto out;

qcom_smccc_convention = ARM_SMCCC_SMC_32;
ret = qcom_scm_call_atomic(NULL, &desc, &res);
if (!ret && res.result[0] == 1)
goto out;

qcom_smccc_convention = -1;
BUG();
out:
pr_info("QCOM SCM SMC Convention: %lld\n", qcom_smccc_convention);
}
146 changes: 145 additions & 1 deletion drivers/firmware/qcom_scm.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -72,6 +72,13 @@ static struct qcom_scm_wb_entry qcom_scm_wb[] = {
{ .flag = QCOM_SCM_FLAG_WARMBOOT_CPU3 },
};

static const char *qcom_scm_convention_names[] = {
[SMC_CONVENTION_UNKNOWN] = "unknown",
[SMC_CONVENTION_ARM_32] = "smc arm 32",
[SMC_CONVENTION_ARM_64] = "smc arm 64",
[SMC_CONVENTION_LEGACY] = "smc legacy",
};

static struct qcom_scm *__scm;

static int qcom_scm_clk_enable(void)
Expand Down Expand Up @@ -107,6 +114,143 @@ static void qcom_scm_clk_disable(void)
clk_disable_unprepare(__scm->bus_clk);
}

static int __qcom_scm_is_call_available(struct device *dev, u32 svc_id,
u32 cmd_id);

enum qcom_scm_convention qcom_scm_convention;
static bool has_queried __read_mostly;
static DEFINE_SPINLOCK(query_lock);

static void __query_convention(void)
{
unsigned long flags;
struct qcom_scm_desc desc = {
.svc = QCOM_SCM_SVC_INFO,
.cmd = QCOM_SCM_INFO_IS_CALL_AVAIL,
.args[0] = SCM_SMC_FNID(QCOM_SCM_SVC_INFO,
QCOM_SCM_INFO_IS_CALL_AVAIL) |
(ARM_SMCCC_OWNER_SIP << ARM_SMCCC_OWNER_SHIFT),
.arginfo = QCOM_SCM_ARGS(1),
.owner = ARM_SMCCC_OWNER_SIP,
};
struct qcom_scm_res res;
int ret;

spin_lock_irqsave(&query_lock, flags);
if (has_queried)
goto out;

qcom_scm_convention = SMC_CONVENTION_ARM_64;
// Device isn't required as there is only one argument - no device
// needed to dma_map_single to secure world
ret = scm_smc_call(NULL, &desc, &res, true);
if (!ret && res.result[0] == 1)
goto out;

qcom_scm_convention = SMC_CONVENTION_ARM_32;
ret = scm_smc_call(NULL, &desc, &res, true);
if (!ret && res.result[0] == 1)
goto out;

qcom_scm_convention = SMC_CONVENTION_LEGACY;
out:
has_queried = true;
spin_unlock_irqrestore(&query_lock, flags);
pr_info("qcom_scm: convention: %s\n",
qcom_scm_convention_names[qcom_scm_convention]);
}

static inline enum qcom_scm_convention __get_convention(void)
{
if (unlikely(!has_queried))
__query_convention();
return qcom_scm_convention;
}

/**
* qcom_scm_call() - Invoke a syscall in the secure world
* @dev: device
* @svc_id: service identifier
* @cmd_id: command identifier
* @desc: Descriptor structure containing arguments and return values
*
* Sends a command to the SCM and waits for the command to finish processing.
* This should *only* be called in pre-emptible context.
*/
static int qcom_scm_call(struct device *dev, const struct qcom_scm_desc *desc,
struct qcom_scm_res *res)
{
might_sleep();
switch (__get_convention()) {
case SMC_CONVENTION_ARM_32:
case SMC_CONVENTION_ARM_64:
return scm_smc_call(dev, desc, res, false);
case SMC_CONVENTION_LEGACY:
return scm_legacy_call(dev, desc, res);
default:
pr_err("Unknown current SCM calling convention.\n");
return -EINVAL;
}
}

/**
* qcom_scm_call_atomic() - atomic variation of qcom_scm_call()
* @dev: device
* @svc_id: service identifier
* @cmd_id: command identifier
* @desc: Descriptor structure containing arguments and return values
* @res: Structure containing results from SMC/HVC call
*
* Sends a command to the SCM and waits for the command to finish processing.
* This can be called in atomic context.
*/
static int qcom_scm_call_atomic(struct device *dev,
const struct qcom_scm_desc *desc,
struct qcom_scm_res *res)
{
switch (__get_convention()) {
case SMC_CONVENTION_ARM_32:
case SMC_CONVENTION_ARM_64:
return scm_smc_call(dev, desc, res, true);
case SMC_CONVENTION_LEGACY:
return scm_legacy_call_atomic(dev, desc, res);
default:
pr_err("Unknown current SCM calling convention.\n");
return -EINVAL;
}
}

static int __qcom_scm_is_call_available(struct device *dev, u32 svc_id,
u32 cmd_id)
{
int ret;
struct qcom_scm_desc desc = {
.svc = QCOM_SCM_SVC_INFO,
.cmd = QCOM_SCM_INFO_IS_CALL_AVAIL,
.owner = ARM_SMCCC_OWNER_SIP,
};
struct qcom_scm_res res;

desc.arginfo = QCOM_SCM_ARGS(1);
switch (__get_convention()) {
case SMC_CONVENTION_ARM_32:
case SMC_CONVENTION_ARM_64:
desc.args[0] = SCM_SMC_FNID(svc_id, cmd_id) |
(ARM_SMCCC_OWNER_SIP << ARM_SMCCC_OWNER_SHIFT);
break;
case SMC_CONVENTION_LEGACY:
desc.args[0] = SCM_LEGACY_FNID(svc_id, cmd_id);
break;
default:
pr_err("Unknown SMC convention being used\n");
return -EINVAL;
}

ret = qcom_scm_call(dev, &desc, &res);

return ret ? : res.result[0];
}

/**
* qcom_scm_set_warm_boot_addr() - Set the warm boot address for cpus
* @entry: Entry point function for the cpus
Expand Down Expand Up @@ -971,7 +1115,7 @@ static int qcom_scm_probe(struct platform_device *pdev)
__scm = scm;
__scm->dev = &pdev->dev;

__qcom_scm_init();
__query_convention();

/*
* If requested enable "download mode", from this point on warmboot
Expand Down
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