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firmware: arm_scmi: Augment SMC/HVC to allow optional parameters

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This change adds support for passing shmem channel address as parameters
in smc/hvc call. The address is split into 4KB-page and offset.
This is useful when multiple scmi instances are using same smc-id
and firmware needs to distinguish among the instances.

Signed-off-by: Nikunj Kela <quic_nkela@quicinc.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230506182428.25343-3-quic_nkela@quicinc.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
This commit is contained in:
Nikunj Kela 2023-05-06 11:24:28 -07:00 committed by Sudeep Holla
parent 8f9d530cff
commit 5f2ea10a80
2 changed files with 30 additions and 1 deletions
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1
drivers/firmware/arm_scmi/driver.c
View File

@ -2914,6 +2914,7 @@ static const struct of_device_id scmi_of_match[] = {
#endif
#ifdef CONFIG_ARM_SCMI_TRANSPORT_SMC
{ .compatible = "arm,scmi-smc", .data = &scmi_smc_desc},
{ .compatible = "arm,scmi-smc-param", .data = &scmi_smc_desc},
#endif
#ifdef CONFIG_ARM_SCMI_TRANSPORT_VIRTIO
{ .compatible = "arm,scmi-virtio", .data = &scmi_virtio_desc},

30
drivers/firmware/arm_scmi/smc.c
View File

@ -20,6 +20,23 @@
#include "common.h"
/*
* The shmem address is split into 4K page and offset.
* This is to make sure the parameters fit in 32bit arguments of the
* smc/hvc call to keep it uniform across smc32/smc64 conventions.
* This however limits the shmem address to 44 bit.
*
* These optional parameters can be used to distinguish among multiple
* scmi instances that are using the same smc-id.
* The page parameter is passed in r1/x1/w1 register and the offset parameter
* is passed in r2/x2/w2 register.
*/
#define SHMEM_SIZE (SZ_4K)
#define SHMEM_SHIFT 12
#define SHMEM_PAGE(x) (_UL((x) >> SHMEM_SHIFT))
#define SHMEM_OFFSET(x) ((x) & (SHMEM_SIZE - 1))
/**
* struct scmi_smc - Structure representing a SCMI smc transport
*
@ -30,6 +47,8 @@
* @inflight: Atomic flag to protect access to Tx/Rx shared memory area.
* Used when operating in atomic mode.
* @func_id: smc/hvc call function id
* @param_page: 4K page number of the shmem channel
* @param_offset: Offset within the 4K page of the shmem channel
*/
struct scmi_smc {
@ -40,6 +59,8 @@ struct scmi_smc {
#define INFLIGHT_NONE MSG_TOKEN_MAX
atomic_t inflight;
u32 func_id;
u32 param_page;
u32 param_offset;
};
static irqreturn_t smc_msg_done_isr(int irq, void *data)
@ -137,6 +158,10 @@ static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
if (ret < 0)
return ret;
if (of_device_is_compatible(dev->of_node, "arm,scmi-smc-param")) {
scmi_info->param_page = SHMEM_PAGE(res.start);
scmi_info->param_offset = SHMEM_OFFSET(res.start);
}
/*
* If there is an interrupt named "a2p", then the service and
* completion of a message is signaled by an interrupt rather than by
@ -179,6 +204,8 @@ static int smc_send_message(struct scmi_chan_info *cinfo,
{
struct scmi_smc *scmi_info = cinfo->transport_info;
struct arm_smccc_res res;
unsigned long page = scmi_info->param_page;
unsigned long offset = scmi_info->param_offset;
/*
* Channel will be released only once response has been
@ -188,7 +215,8 @@ static int smc_send_message(struct scmi_chan_info *cinfo,
shmem_tx_prepare(scmi_info->shmem, xfer, cinfo);
arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
arm_smccc_1_1_invoke(scmi_info->func_id, page, offset, 0, 0, 0, 0, 0,
&res);
/* Only SMCCC_RET_NOT_SUPPORTED is valid error code */
if (res.a0) {