linux-kernel - [PATCH 8/9] remoteproc: core: Skip resource table integrity checks if there are amendments

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Date:	Thu,  4 Aug 2016 10:21:52 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:	kernel@...inux.com, patrice.chotard@...com, ohad@...ery.com,
	bjorn.andersson@...aro.org, linux-remoteproc@...r.kernel.org,
	loic.pallardy@...com, Lee Jones <lee.jones@...aro.org>
Subject: [PATCH 8/9] remoteproc: core: Skip resource table integrity checks if there are amendments

There is little point wasting CPU cycles completing integrity checking
(i.e. ensuring nothing has changed) on the resource table if we *know*
that it will be changed (by us).  In this patch we skip resource table
integrity checks if a platform-specific remoteproc driver has requested
an amendment or an appended entry.

Signed-off-by: Lee Jones <lee.jones@...aro.org>
---
 drivers/remoteproc/remoteproc_core.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 6b4e29a..9a077e4 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -1126,6 +1126,10 @@ static int rproc_fw_boot(struct rproc *rproc, const struct firmware *fw)
 	rproc->bootaddr = rproc_get_boot_addr(rproc, fw);
 	ret = -EINVAL;
 
+	/* If we've overridden the resource table, we know it's changed. */
+	if (!list_empty(&rproc->override_resources))
+		goto skip_table_check;
+
 	/* look for the resource table */
 	table = rproc_find_rsc_table(rproc, fw, &tablesz);
 	if (!table) {
@@ -1139,6 +1143,8 @@ static int rproc_fw_boot(struct rproc *rproc, const struct firmware *fw)
 		goto clean_up;
 	}
 
+ skip_table_check:
+
 	/* handle fw resources which are required to boot rproc */
 	ret = rproc_handle_resources(rproc, tablesz, rproc_loading_handlers);
 	if (ret) {
@@ -1216,10 +1222,15 @@ static void rproc_fw_config_virtio(const struct firmware *fw, void *context)
 		table = rproc_apply_resource_overrides(rproc, &table, &tablesz);
 		if (IS_ERR(table))
 			goto out;
+
+		/* No point checking table if we know it *has* changed */
+		goto skip_table_check;
 	}
 
 	rproc->table_csum = crc32(0, table, tablesz);
 
+ skip_table_check:
+
 	/*
 	 * Create a copy of the resource table. When a virtio device starts
 	 * and calls vring_new_virtqueue() the address of the allocated vring
-- 
2.9.0