This change adds the support for SCMI message exchange on Qualcomm
virtual platforms.
The hypervisor associates an object-id also known as capability-id
with each smc/hvc doorbell object. The capability-id is used to
identify the doorbell from the VM's capability namespace, similar
to a file-descriptor.
The hypervisor, in addition to the function-id, expects the capability-id
to be passed in x1 register when SMC/HVC call is invoked.
The capability-id is allocated by the hypervisor on bootup and is stored in
the shmem region by the firmware before starting Linux.
Signed-off-by: Nikunj Kela <quic_nkela@xxxxxxxxxxx>
Reviewed-by: Brian Masney <bmasney@xxxxxxxxxx>
Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
---
drivers/firmware/arm_scmi/driver.c | 1 +
drivers/firmware/arm_scmi/smc.c | 27 +++++++++++++++++++++++++--
2 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 87383c05424b..09371f40d61f 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -2915,6 +2915,7 @@ static const struct of_device_id scmi_of_match[] = {
#ifdef CONFIG_ARM_SCMI_TRANSPORT_SMC
{ .compatible = "arm,scmi-smc", .data = &scmi_smc_desc},
{ .compatible = "arm,scmi-smc-param", .data = &scmi_smc_desc},
+ { .compatible = "qcom,scmi-smc", .data = &scmi_smc_desc},
#endif
#ifdef CONFIG_ARM_SCMI_TRANSPORT_VIRTIO
{ .compatible = "arm,scmi-virtio", .data = &scmi_virtio_desc},
diff --git a/drivers/firmware/arm_scmi/smc.c b/drivers/firmware/arm_scmi/smc.c
index 8eba60a41975..7611e9665038 100644
--- a/drivers/firmware/arm_scmi/smc.c
+++ b/drivers/firmware/arm_scmi/smc.c
@@ -15,6 +15,7 @@
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
+#include <linux/limits.h>
#include <linux/processor.h>
#include <linux/slab.h>
@@ -50,6 +51,8 @@
* @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
+ * @cap_id: smc/hvc doorbell's capability id to be used on Qualcomm virtual
+ * platforms
*/
struct scmi_smc {
@@ -63,6 +66,7 @@ struct scmi_smc {
unsigned long func_id;
unsigned long param_page;
unsigned long param_offset;
+ unsigned long cap_id;
};
static irqreturn_t smc_msg_done_isr(int irq, void *data)
@@ -124,6 +128,7 @@ static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
bool tx)
{
struct device *cdev = cinfo->dev;
+ unsigned long cap_id = ULONG_MAX;
struct scmi_smc *scmi_info;
resource_size_t size;
struct resource res;
@@ -162,6 +167,18 @@ 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, "qcom,scmi-smc")) {
+ void __iomem *ptr = (void __iomem *)scmi_info->shmem + size - 8;
+ /* The capability-id is kept in last 8 bytes of shmem.
+ * +-------+ <-- 0
+ * | shmem |
+ * +-------+ <-- size - 8
+ * | capId |
+ * +-------+ <-- size
+ */
+ memcpy_fromio(&cap_id, ptr, sizeof(cap_id));
+ }
+
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);
@@ -184,6 +201,7 @@ static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
}
scmi_info->func_id = func_id;
+ scmi_info->cap_id = cap_id;
scmi_info->cinfo = cinfo;
smc_channel_lock_init(scmi_info);
cinfo->transport_info = scmi_info;
@@ -220,8 +238,13 @@ 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, scmi_info->param_page,
- scmi_info->param_offset, 0, 0, 0, 0, 0, &res);
+ if (scmi_info->cap_id != ULONG_MAX)
+ arm_smccc_1_1_invoke(scmi_info->func_id, scmi_info->cap_id, 0,
+ 0, 0, 0, 0, 0, &res);
+ else
+ arm_smccc_1_1_invoke(scmi_info->func_id, scmi_info->param_page,
+ scmi_info->param_offset, 0, 0, 0, 0, 0,
+ &res);
/* Only SMCCC_RET_NOT_SUPPORTED is valid error code */
if (res.a0) {
--
2.17.1
