firmware: qcom_scm: Add qcom_scm_pas_get_rsc_table() to get resource table

Qualcomm remote processor may rely on Static and Dynamic resources for
it to be functional. Static resources are fixed like for example,
memory-mapped addresses required by the subsystem and dynamic
resources, such as shared memory in DDR etc., are determined at
runtime during the boot process.

For most of the Qualcomm SoCs, when run with Gunyah or older QHEE
hypervisor, all the resources whether it is static or dynamic, is
managed by the hypervisor. Dynamic resources if it is present for a
remote processor will always be coming from secure world via SMC call
while static resources may be present in remote processor firmware
binary or it may be coming qcom_scm_pas_get_rsc_table() SMC call along
with dynamic resources.

Some of the remote processor drivers, such as video, GPU, IPA, etc., do
not check whether resources are present in their remote processor
firmware binary. In such cases, the caller of this function should set
input_rt and input_rt_size as NULL and zero respectively. Remoteproc
framework has method to check whether firmware binary contain resources
or not and they should be pass resource table pointer to input_rt and
resource table size to input_rt_size and this will be forwarded to
TrustZone for authentication. TrustZone will then append the dynamic
resources and return the complete resource table in the passed output
buffer.

More about documentation on resource table format can be found in
include/linux/remoteproc.h

Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260105-kvmrprocv10-v10-11-022e96815380@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Author: mukeshojha-linux

drivers/firmware/qcom/qcom_scm.c

@@ -27,6 +27,7 @@
 #include <linux/of_reserved_mem.h>
 #include <linux/platform_device.h>
 #include <linux/reset-controller.h>
+#include <linux/remoteproc.h>
 #include <linux/sizes.h>
 #include <linux/types.h>
 
@@ -111,6 +112,8 @@ enum qcom_scm_qseecom_tz_cmd_info {
 	QSEECOM_TZ_CMD_INFO_VERSION		= 3,
 };
 
+#define RSCTABLE_BUFFER_NOT_SUFFICIENT		20
+
 #define QSEECOM_MAX_APP_NAME_SIZE		64
 #define SHMBRIDGE_RESULT_NOTSUPP		4
 
@@ -766,6 +769,174 @@ int qcom_scm_pas_mem_setup(u32 pas_id, phys_addr_t addr, phys_addr_t size)
 }
 EXPORT_SYMBOL_GPL(qcom_scm_pas_mem_setup);
 
+static void *__qcom_scm_pas_get_rsc_table(u32 pas_id, void *input_rt_tzm,
+					  size_t input_rt_size,
+					  size_t *output_rt_size)
+{
+	struct qcom_scm_desc desc = {
+		.svc = QCOM_SCM_SVC_PIL,
+		.cmd = QCOM_SCM_PIL_PAS_GET_RSCTABLE,
+		.arginfo = QCOM_SCM_ARGS(5, QCOM_SCM_VAL, QCOM_SCM_RO, QCOM_SCM_VAL,
+					 QCOM_SCM_RW, QCOM_SCM_VAL),
+		.args[0] = pas_id,
+		.owner = ARM_SMCCC_OWNER_SIP,
+	};
+	struct qcom_scm_res res;
+	void *output_rt_tzm;
+	int ret;
+
+	output_rt_tzm = qcom_tzmem_alloc(__scm->mempool, *output_rt_size, GFP_KERNEL);
+	if (!output_rt_tzm)
+		return ERR_PTR(-ENOMEM);
+
+	desc.args[1] = qcom_tzmem_to_phys(input_rt_tzm);
+	desc.args[2] = input_rt_size;
+	desc.args[3] = qcom_tzmem_to_phys(output_rt_tzm);
+	desc.args[4] = *output_rt_size;
+
+	/*
+	 * Whether SMC fail or pass, res.result[2] will hold actual resource table
+	 * size.
+	 *
+	 * If passed 'output_rt_size' buffer size is not sufficient to hold the
+	 * resource table TrustZone sends, response code in res.result[1] as
+	 * RSCTABLE_BUFFER_NOT_SUFFICIENT so that caller can retry this SMC call
+	 * with output_rt_tzm buffer with res.result[2] size however, It should not
+	 * be of unresonable size.
+	 */
+	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	if (!ret && res.result[2] > SZ_1G) {
+		ret = -E2BIG;
+		goto free_output_rt;
+	}
+
+	*output_rt_size = res.result[2];
+	if (ret && res.result[1] == RSCTABLE_BUFFER_NOT_SUFFICIENT)
+		ret = -EOVERFLOW;
+
+free_output_rt:
+	if (ret)
+		qcom_tzmem_free(output_rt_tzm);
+
+	return ret ? ERR_PTR(ret) : output_rt_tzm;
+}
+
+/**
+ * qcom_scm_pas_get_rsc_table() - Retrieve the resource table in passed output buffer
+ *				  for a given peripheral.
+ *
+ * Qualcomm remote processor may rely on both static and dynamic resources for
+ * its functionality. Static resources typically refer to memory-mapped addresses
+ * required by the subsystem and are often embedded within the firmware binary
+ * and dynamic resources, such as shared memory in DDR etc., are determined at
+ * runtime during the boot process.
+ *
+ * On Qualcomm Technologies devices, it's possible that static resources are not
+ * embedded in the firmware binary and instead are provided by TrustZone However,
+ * dynamic resources are always expected to come from TrustZone. This indicates
+ * that for Qualcomm devices, all resources (static and dynamic) will be provided
+ * by TrustZone via the SMC call.
+ *
+ * If the remote processor firmware binary does contain static resources, they
+ * should be passed in input_rt. These will be forwarded to TrustZone for
+ * authentication. TrustZone will then append the dynamic resources and return
+ * the complete resource table in output_rt_tzm.
+ *
+ * If the remote processor firmware binary does not include a resource table,
+ * the caller of this function should set input_rt as NULL and input_rt_size
+ * as zero respectively.
+ *
+ * More about documentation on resource table data structures can be found in
+ * include/linux/remoteproc.h
+ *
+ * @ctx:	    PAS context
+ * @pas_id:	    peripheral authentication service id
+ * @input_rt:       resource table buffer which is present in firmware binary
+ * @input_rt_size:  size of the resource table present in firmware binary
+ * @output_rt_size: TrustZone expects caller should pass worst case size for
+ *		    the output_rt_tzm.
+ *
+ * Return:
+ *  On success, returns a pointer to the allocated buffer containing the final
+ *  resource table and output_rt_size will have actual resource table size from
+ *  TrustZone. The caller is responsible for freeing the buffer. On failure,
+ *  returns ERR_PTR(-errno).
+ */
+struct resource_table *qcom_scm_pas_get_rsc_table(struct qcom_scm_pas_context *ctx,
+						  void *input_rt,
+						  size_t input_rt_size,
+						  size_t *output_rt_size)
+{
+	struct resource_table empty_rsc = {};
+	size_t size = SZ_16K;
+	void *output_rt_tzm;
+	void *input_rt_tzm;
+	void *tbl_ptr;
+	int ret;
+
+	ret = qcom_scm_clk_enable();
+	if (ret)
+		return ERR_PTR(ret);
+
+	ret = qcom_scm_bw_enable();
+	if (ret)
+		goto disable_clk;
+
+	/*
+	 * TrustZone can not accept buffer as NULL value as argument hence,
+	 * we need to pass a input buffer indicating that subsystem firmware
+	 * does not have resource table by filling resource table structure.
+	 */
+	if (!input_rt) {
+		input_rt = &empty_rsc;
+		input_rt_size = sizeof(empty_rsc);
+	}
+
+	input_rt_tzm = qcom_tzmem_alloc(__scm->mempool, input_rt_size, GFP_KERNEL);
+	if (!input_rt_tzm) {
+		ret = -ENOMEM;
+		goto disable_scm_bw;
+	}
+
+	memcpy(input_rt_tzm, input_rt, input_rt_size);
+
+	output_rt_tzm = __qcom_scm_pas_get_rsc_table(ctx->pas_id, input_rt_tzm,
+						     input_rt_size, &size);
+	if (PTR_ERR(output_rt_tzm) == -EOVERFLOW)
+		/* Try again with the size requested by the TZ */
+		output_rt_tzm = __qcom_scm_pas_get_rsc_table(ctx->pas_id,
+							     input_rt_tzm,
+							     input_rt_size,
+							     &size);
+	if (IS_ERR(output_rt_tzm)) {
+		ret = PTR_ERR(output_rt_tzm);
+		goto free_input_rt;
+	}
+
+	tbl_ptr = kzalloc(size, GFP_KERNEL);
+	if (!tbl_ptr) {
+		qcom_tzmem_free(output_rt_tzm);
+		ret = -ENOMEM;
+		goto free_input_rt;
+	}
+
+	memcpy(tbl_ptr, output_rt_tzm, size);
+	*output_rt_size = size;
+	qcom_tzmem_free(output_rt_tzm);
+
+free_input_rt:
+	qcom_tzmem_free(input_rt_tzm);
+
+disable_scm_bw:
+	qcom_scm_bw_disable();
+
+disable_clk:
+	qcom_scm_clk_disable();
+
+	return ret ? ERR_PTR(ret) : tbl_ptr;
+}
+EXPORT_SYMBOL_GPL(qcom_scm_pas_get_rsc_table);
+
 /**
  * qcom_scm_pas_auth_and_reset() - Authenticate the given peripheral firmware
  *				   and reset the remote processor

drivers/firmware/qcom/qcom_scm.h

@@ -105,6 +105,7 @@ int qcom_scm_shm_bridge_enable(struct device *scm_dev);
 #define QCOM_SCM_PIL_PAS_SHUTDOWN	0x06
 #define QCOM_SCM_PIL_PAS_IS_SUPPORTED	0x07
 #define QCOM_SCM_PIL_PAS_MSS_RESET	0x0a
+#define QCOM_SCM_PIL_PAS_GET_RSCTABLE	0x21
 
 #define QCOM_SCM_SVC_IO			0x05
 #define QCOM_SCM_IO_READ		0x01

include/linux/firmware/qcom/qcom_scm.h

@@ -88,6 +88,10 @@ int qcom_scm_pas_mem_setup(u32 pas_id, phys_addr_t addr, phys_addr_t size);
 int qcom_scm_pas_auth_and_reset(u32 pas_id);
 int qcom_scm_pas_shutdown(u32 pas_id);
 bool qcom_scm_pas_supported(u32 pas_id);
+struct resource_table *qcom_scm_pas_get_rsc_table(struct qcom_scm_pas_context *ctx,
+						  void *input_rt, size_t input_rt_size,
+						  size_t *output_rt_size);
+
 int qcom_scm_pas_prepare_and_auth_reset(struct qcom_scm_pas_context *ctx);
 
 int qcom_scm_io_readl(phys_addr_t addr, unsigned int *val);