linux-kernel - [PATCH] soc: fsl: dpio: fix incorrect pointer conversions

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Message-Id: <20200408185904.460563-1-arnd@arndb.de>
Date:   Wed,  8 Apr 2020 20:58:58 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     soc@...nel.org, Roy Pledge <Roy.Pledge@....com>,
        Li Yang <leoyang.li@....com>,
        Youri Querry <youri.querry_1@....com>
Cc:     Arnd Bergmann <arnd@...db.de>, Roy Pledge <roy.pledge@....com>,
        Colin Ian King <colin.king@...onical.com>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH] soc: fsl: dpio: fix incorrect pointer conversions

Building dpio for 32 bit shows a new compiler warning from converting
a pointer to a u64:

drivers/soc/fsl/dpio/qbman-portal.c: In function 'qbman_swp_enqueue_multiple_desc_direct':
drivers/soc/fsl/dpio/qbman-portal.c:870:14: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
  870 |  addr_cena = (uint64_t)s->addr_cena;

The variable is not used anywhere, so removing the assignment seems
to be the correct workaround. After spotting what seemed to be
some confusion about address spaces, I ran the file through sparse,
which showed more warnings:

drivers/soc/fsl/dpio/qbman-portal.c:756:42: warning: incorrect type in argument 1 (different address spaces)
drivers/soc/fsl/dpio/qbman-portal.c:756:42:    expected void const volatile [noderef] <asn:2> *addr
drivers/soc/fsl/dpio/qbman-portal.c:756:42:    got unsigned int [usertype] *[assigned] p
drivers/soc/fsl/dpio/qbman-portal.c:902:42: warning: incorrect type in argument 1 (different address spaces)
drivers/soc/fsl/dpio/qbman-portal.c:902:42:    expected void const volatile [noderef] <asn:2> *addr
drivers/soc/fsl/dpio/qbman-portal.c:902:42:    got unsigned int [usertype] *[assigned] p

Here, the problem is passing a token from memremap() into __raw_readl(),
which is only defined to work on MMIO addresses but not RAM. Turning
this into a simple pointer dereference avoids this warning as well.

Fixes: 3b2abda7d28c ("soc: fsl: dpio: Replace QMAN array mode with ring mode enqueue")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/soc/fsl/dpio/qbman-portal.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/soc/fsl/dpio/qbman-portal.c b/drivers/soc/fsl/dpio/qbman-portal.c
index d1f49caa5b13..804b8ba9bf5c 100644
--- a/drivers/soc/fsl/dpio/qbman-portal.c
+++ b/drivers/soc/fsl/dpio/qbman-portal.c
@@ -753,7 +753,7 @@ int qbman_swp_enqueue_multiple_mem_back(struct qbman_swp *s,
 	if (!s->eqcr.available) {
 		eqcr_ci = s->eqcr.ci;
 		p = s->addr_cena + QBMAN_CENA_SWP_EQCR_CI_MEMBACK;
-		s->eqcr.ci = __raw_readl(p) & full_mask;
+		s->eqcr.ci = *p & full_mask;
 		s->eqcr.available = qm_cyc_diff(s->eqcr.pi_ring_size,
 					eqcr_ci, s->eqcr.ci);
 		if (!s->eqcr.available) {
@@ -823,7 +823,6 @@ int qbman_swp_enqueue_multiple_desc_direct(struct qbman_swp *s,
 	const uint32_t *cl;
 	uint32_t eqcr_ci, eqcr_pi, half_mask, full_mask;
 	int i, num_enqueued = 0;
-	uint64_t addr_cena;
 
 	half_mask = (s->eqcr.pi_ci_mask>>1);
 	full_mask = s->eqcr.pi_ci_mask;
@@ -867,7 +866,6 @@ int qbman_swp_enqueue_multiple_desc_direct(struct qbman_swp *s,
 
 	/* Flush all the cacheline without load/store in between */
 	eqcr_pi = s->eqcr.pi;
-	addr_cena = (uint64_t)s->addr_cena;
 	for (i = 0; i < num_enqueued; i++)
 		eqcr_pi++;
 	s->eqcr.pi = eqcr_pi & full_mask;
@@ -901,7 +899,7 @@ int qbman_swp_enqueue_multiple_desc_mem_back(struct qbman_swp *s,
 	if (!s->eqcr.available) {
 		eqcr_ci = s->eqcr.ci;
 		p = s->addr_cena + QBMAN_CENA_SWP_EQCR_CI_MEMBACK;
-		s->eqcr.ci = __raw_readl(p) & full_mask;
+		s->eqcr.ci = *p & full_mask;
 		s->eqcr.available = qm_cyc_diff(s->eqcr.pi_ring_size,
 					eqcr_ci, s->eqcr.ci);
 		if (!s->eqcr.available)
-- 
2.26.0