Commit da405477 authored by Nikunj Kela's avatar Nikunj Kela Committed by Sudeep Holla
Browse files

firmware: arm_scmi: Add qcom smc/hvc transport support 



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: default avatarNikunj Kela <quic_nkela@quicinc.com>
Reviewed-by: default avatarBrian Masney <bmasney@redhat.com>
Link: https://lore.kernel.org/r/20231009191437.27926-3-quic_nkela@quicinc.com


Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
parent 6979f88f

drivers/firmware/arm_scmi/driver.c

+1 −0
Original line number Diff line number Diff line
@@ -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},

drivers/firmware/arm_scmi/smc.c

+25 −2
Original line number Diff line number Diff line
@@ -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);



	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);

				     scmi_info->param_offset, 0, 0, 0, 0, 0,

				     &res);



	/* Only SMCCC_RET_NOT_SUPPORTED is valid error code */

	if (res.a0) {