firmware: qcom: scm: Convert to streaming DMA APIS

This patch converts the Qualcomm SCM driver to use the streaming DMA APIs
for communication buffers.  This is being done so that the
secure_flush_area call can be removed.  Using the DMA APIs will also make
the SCM32 symmetric to the coming SCM64 code.
Signed-off-by: Andy Gross <andy.gross@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/firmware/qcom_scm-32.c

@@ -23,8 +23,7 @@
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/qcom_scm.h>
-
-#include <asm/cacheflush.h>
+#include <linux/dma-mapping.h>
 
 #include "qcom_scm.h"
 
@@ -96,44 +95,6 @@ struct qcom_scm_response {
 	__le32 is_complete;
 };
 
-/**
- * alloc_qcom_scm_command() - Allocate an SCM command
- * @cmd_size: size of the command buffer
- * @resp_size: size of the response buffer
- *
- * Allocate an SCM command, including enough room for the command
- * and response headers as well as the command and response buffers.
- *
- * Returns a valid &qcom_scm_command on success or %NULL if the allocation fails.
- */
-static struct qcom_scm_command *alloc_qcom_scm_command(size_t cmd_size, size_t resp_size)
-{
-	struct qcom_scm_command *cmd;
-	size_t len = sizeof(*cmd) + sizeof(struct qcom_scm_response) + cmd_size +
-		resp_size;
-	u32 offset;
-
-	cmd = kzalloc(PAGE_ALIGN(len), GFP_KERNEL);
-	if (cmd) {
-		cmd->len = cpu_to_le32(len);
-		offset = offsetof(struct qcom_scm_command, buf);
-		cmd->buf_offset = cpu_to_le32(offset);
-		cmd->resp_hdr_offset = cpu_to_le32(offset + cmd_size);
-	}
-	return cmd;
-}
-
-/**
- * free_qcom_scm_command() - Free an SCM command
- * @cmd: command to free
- *
- * Free an SCM command.
- */
-static inline void free_qcom_scm_command(struct qcom_scm_command *cmd)
-{
-	kfree(cmd);
-}
-
 /**
  * qcom_scm_command_to_response() - Get a pointer to a qcom_scm_response
  * @cmd: command
@@ -192,45 +153,9 @@ static u32 smc(u32 cmd_addr)
 	return r0;
 }
 
-static int __qcom_scm_call(const struct qcom_scm_command *cmd)
-{
-	int ret;
-	u32 cmd_addr = virt_to_phys(cmd);
-
-	/*
-	 * Flush the command buffer so that the secure world sees
-	 * the correct data.
-	 */
-	secure_flush_area(cmd, cmd->len);
-
-	ret = smc(cmd_addr);
-	if (ret < 0)
-		ret = qcom_scm_remap_error(ret);
-
-	return ret;
-}
-
-static void qcom_scm_inv_range(unsigned long start, unsigned long end)
-{
-	u32 cacheline_size, ctr;
-
-	asm volatile("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr));
-	cacheline_size = 4 << ((ctr >> 16) & 0xf);
-
-	start = round_down(start, cacheline_size);
-	end = round_up(end, cacheline_size);
-	outer_inv_range(start, end);
-	while (start < end) {
-		asm ("mcr p15, 0, %0, c7, c6, 1" : : "r" (start)
-		     : "memory");
-		start += cacheline_size;
-	}
-	dsb();
-	isb();
-}
-
 /**
  * qcom_scm_call() - Send an SCM command
+ * @dev: struct device
  * @svc_id: service identifier
  * @cmd_id: command identifier
  * @cmd_buf: command buffer
@@ -247,42 +172,59 @@ static void qcom_scm_inv_range(unsigned long start, unsigned long end)
  * and response buffers is taken care of by qcom_scm_call; however, callers are
  * responsible for any other cached buffers passed over to the secure world.
  */
-static int qcom_scm_call(u32 svc_id, u32 cmd_id, const void *cmd_buf,
-			size_t cmd_len, void *resp_buf, size_t resp_len)
+static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
+			 const void *cmd_buf, size_t cmd_len, void *resp_buf,
+			 size_t resp_len)
 {
 	int ret;
 	struct qcom_scm_command *cmd;
 	struct qcom_scm_response *rsp;
-	unsigned long start, end;
+	size_t alloc_len = sizeof(*cmd) + cmd_len + sizeof(*rsp) + resp_len;
+	dma_addr_t cmd_phys;
 
-	cmd = alloc_qcom_scm_command(cmd_len, resp_len);
+	cmd = kzalloc(PAGE_ALIGN(alloc_len), GFP_KERNEL);
 	if (!cmd)
 		return -ENOMEM;
 
+	cmd->len = cpu_to_le32(alloc_len);
+	cmd->buf_offset = cpu_to_le32(sizeof(*cmd));
+	cmd->resp_hdr_offset = cpu_to_le32(sizeof(*cmd) + cmd_len);
+
 	cmd->id = cpu_to_le32((svc_id << 10) | cmd_id);
 	if (cmd_buf)
 		memcpy(qcom_scm_get_command_buffer(cmd), cmd_buf, cmd_len);
 
+	rsp = qcom_scm_command_to_response(cmd);
+
+	cmd_phys = dma_map_single(dev, cmd, alloc_len, DMA_TO_DEVICE);
+	if (dma_mapping_error(dev, cmd_phys)) {
+		kfree(cmd);
+		return -ENOMEM;
+	}
+
 	mutex_lock(&qcom_scm_lock);
-	ret = __qcom_scm_call(cmd);
+	ret = smc(cmd_phys);
+	if (ret < 0)
+		ret = qcom_scm_remap_error(ret);
 	mutex_unlock(&qcom_scm_lock);
 	if (ret)
 		goto out;
 
-	rsp = qcom_scm_command_to_response(cmd);
-	start = (unsigned long)rsp;
-
 	do {
-		qcom_scm_inv_range(start, start + sizeof(*rsp));
+		dma_sync_single_for_cpu(dev, cmd_phys + sizeof(*cmd) + cmd_len,
+					sizeof(*rsp), DMA_FROM_DEVICE);
 	} while (!rsp->is_complete);
 
-	end = (unsigned long)qcom_scm_get_response_buffer(rsp) + resp_len;
-	qcom_scm_inv_range(start, end);
-
-	if (resp_buf)
-		memcpy(resp_buf, qcom_scm_get_response_buffer(rsp), resp_len);
+	if (resp_buf) {
+		dma_sync_single_for_cpu(dev, cmd_phys + sizeof(*cmd) + cmd_len +
+					le32_to_cpu(rsp->buf_offset),
+					resp_len, DMA_FROM_DEVICE);
+		memcpy(resp_buf, qcom_scm_get_response_buffer(rsp),
+		       resp_len);
+	}
 out:
-	free_qcom_scm_command(cmd);
+	dma_unmap_single(dev, cmd_phys, alloc_len, DMA_TO_DEVICE);
+	kfree(cmd);
 	return ret;
 }
 
@@ -437,7 +379,8 @@ int __qcom_scm_set_cold_boot_addr(void *entry, const cpumask_t *cpus)
  * Set the Linux entry point for the SCM to transfer control to when coming
  * out of a power down. CPU power down may be executed on cpuidle or hotplug.
  */
-int __qcom_scm_set_warm_boot_addr(void *entry, const cpumask_t *cpus)
+int __qcom_scm_set_warm_boot_addr(struct device *dev, void *entry,
+				  const cpumask_t *cpus)
 {
 	int ret;
 	int flags = 0;
@@ -463,7 +406,7 @@ int __qcom_scm_set_warm_boot_addr(void *entry, const cpumask_t *cpus)
 
 	cmd.addr = cpu_to_le32(virt_to_phys(entry));
 	cmd.flags = cpu_to_le32(flags);
-	ret = qcom_scm_call(QCOM_SCM_SVC_BOOT, QCOM_SCM_BOOT_ADDR,
+	ret = qcom_scm_call(dev, QCOM_SCM_SVC_BOOT, QCOM_SCM_BOOT_ADDR,
 			    &cmd, sizeof(cmd), NULL, 0);
 	if (!ret) {
 		for_each_cpu(cpu, cpus)
@@ -487,25 +430,27 @@ void __qcom_scm_cpu_power_down(u32 flags)
 			flags & QCOM_SCM_FLUSH_FLAG_MASK);
 }
 
-int __qcom_scm_is_call_available(u32 svc_id, u32 cmd_id)
+int __qcom_scm_is_call_available(struct device *dev, u32 svc_id, u32 cmd_id)
 {
 	int ret;
 	__le32 svc_cmd = cpu_to_le32((svc_id << 10) | cmd_id);
 	__le32 ret_val = 0;
 
-	ret = qcom_scm_call(QCOM_SCM_SVC_INFO, QCOM_IS_CALL_AVAIL_CMD, &svc_cmd,
-			sizeof(svc_cmd), &ret_val, sizeof(ret_val));
+	ret = qcom_scm_call(dev, QCOM_SCM_SVC_INFO, QCOM_IS_CALL_AVAIL_CMD,
+			    &svc_cmd, sizeof(svc_cmd), &ret_val,
+			    sizeof(ret_val));
 	if (ret)
 		return ret;
 
 	return le32_to_cpu(ret_val);
 }
 
-int __qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp)
+int __qcom_scm_hdcp_req(struct device *dev, struct qcom_scm_hdcp_req *req,
+			u32 req_cnt, u32 *resp)
 {
 	if (req_cnt > QCOM_SCM_HDCP_MAX_REQ_CNT)
 		return -ERANGE;
 
-	return qcom_scm_call(QCOM_SCM_SVC_HDCP, QCOM_SCM_CMD_HDCP,
+	return qcom_scm_call(dev, QCOM_SCM_SVC_HDCP, QCOM_SCM_CMD_HDCP,
 		req, req_cnt * sizeof(*req), resp, sizeof(*resp));
 }

drivers/firmware/qcom_scm.c

@@ -89,7 +89,7 @@ EXPORT_SYMBOL(qcom_scm_set_cold_boot_addr);
  */
 int qcom_scm_set_warm_boot_addr(void *entry, const cpumask_t *cpus)
 {
-	return __qcom_scm_set_warm_boot_addr(entry, cpus);
+	return __qcom_scm_set_warm_boot_addr(__scm->dev, entry, cpus);
 }
 EXPORT_SYMBOL(qcom_scm_set_warm_boot_addr);
 
@@ -119,7 +119,7 @@ bool qcom_scm_hdcp_available(void)
 	if (ret)
 		return ret;
 
-	ret = __qcom_scm_is_call_available(QCOM_SCM_SVC_HDCP,
+	ret = __qcom_scm_is_call_available(__scm->dev, QCOM_SCM_SVC_HDCP,
 						QCOM_SCM_CMD_HDCP);
 
 	qcom_scm_clk_disable();
@@ -143,7 +143,7 @@ int qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp)
 	if (ret)
 		return ret;
 
-	ret = __qcom_scm_hdcp_req(req, req_cnt, resp);
+	ret = __qcom_scm_hdcp_req(__scm->dev, req, req_cnt, resp);
 	qcom_scm_clk_disable();
 	return ret;
 }

drivers/firmware/qcom_scm.h

@@ -19,7 +19,8 @@
 #define QCOM_SCM_FLAG_HLOS		0x01
 #define QCOM_SCM_FLAG_COLDBOOT_MC	0x02
 #define QCOM_SCM_FLAG_WARMBOOT_MC	0x04
-extern int __qcom_scm_set_warm_boot_addr(void *entry, const cpumask_t *cpus);
+extern int __qcom_scm_set_warm_boot_addr(struct device *dev, void *entry,
+		const cpumask_t *cpus);
 extern int __qcom_scm_set_cold_boot_addr(void *entry, const cpumask_t *cpus);
 
 #define QCOM_SCM_CMD_TERMINATE_PC	0x2
@@ -29,12 +30,13 @@ extern void __qcom_scm_cpu_power_down(u32 flags);
 
 #define QCOM_SCM_SVC_INFO		0x6
 #define QCOM_IS_CALL_AVAIL_CMD		0x1
-extern int __qcom_scm_is_call_available(u32 svc_id, u32 cmd_id);
+extern int __qcom_scm_is_call_available(struct device *dev, u32 svc_id,
+		u32 cmd_id);
 
 #define QCOM_SCM_SVC_HDCP		0x11
 #define QCOM_SCM_CMD_HDCP		0x01
-extern int __qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt,
-		u32 *resp);
+extern int __qcom_scm_hdcp_req(struct device *dev,
+		struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp);
 
 /* common error codes */
 #define QCOM_SCM_ENOMEM		-5