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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>
This commit is contained in:
Elliot Berman
2020-01-07 13:04:26 -08:00
committed by Bjorn Andersson
parent 57d3b81671
commit 9a434cee77
6 changed files with 176 additions and 135 deletions
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146
drivers/firmware/qcom_scm.c
View File

@@ -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)
@@ -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
@@ -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