From: Alexander Usyskin <alexander.usyskin@intel.com>
Date: Tue, 17 Jun 2025 14:51:55 +0000 (+0300)
Subject: mtd: intel-dg: align 64bit read and write
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4b93f5fc3bdff9e89beb7aa7f39ca8c7e4d02924;p=thirdparty%2Flinux.git

mtd: intel-dg: align 64bit read and write

GSC NVM controller HW errors on quad access overlapping 1K border.
Align 64bit read and write to avoid readq/writeq over 1K border.

Reviewed-by: Raag Jadav <raag.jadav@intel.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Link: https://lore.kernel.org/r/20250617145159.3803852-6-alexander.usyskin@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
---

diff --git a/drivers/mtd/devices/mtd_intel_dg.c b/drivers/mtd/devices/mtd_intel_dg.c
index 6d971fb779380..97e1dc1ada5dc 100644
--- a/drivers/mtd/devices/mtd_intel_dg.c
+++ b/drivers/mtd/devices/mtd_intel_dg.c
@@ -246,6 +246,24 @@ static ssize_t idg_write(struct intel_dg_nvm *nvm, u8 region,
 		len_s -= to_shift;
 	}
 
+	if (!IS_ALIGNED(to, sizeof(u64)) &&
+	    ((to ^ (to + len_s)) & GENMASK(31, 10))) {
+		/*
+		 * Workaround reads/writes across 1k-aligned addresses
+		 * (start u32 before 1k, end u32 after)
+		 * as this fails on hardware.
+		 */
+		u32 data;
+
+		memcpy(&data, &buf[0], sizeof(u32));
+		idg_nvm_write32(nvm, to, data);
+		if (idg_nvm_error(nvm))
+			return -EIO;
+		buf += sizeof(u32);
+		to += sizeof(u32);
+		len_s -= sizeof(u32);
+	}
+
 	len8 = ALIGN_DOWN(len_s, sizeof(u64));
 	for (i = 0; i < len8; i += sizeof(u64)) {
 		u64 data;
@@ -303,6 +321,23 @@ static ssize_t idg_read(struct intel_dg_nvm *nvm, u8 region,
 		from += from_shift;
 	}
 
+	if (!IS_ALIGNED(from, sizeof(u64)) &&
+	    ((from ^ (from + len_s)) & GENMASK(31, 10))) {
+		/*
+		 * Workaround reads/writes across 1k-aligned addresses
+		 * (start u32 before 1k, end u32 after)
+		 * as this fails on hardware.
+		 */
+		u32 data = idg_nvm_read32(nvm, from);
+
+		if (idg_nvm_error(nvm))
+			return -EIO;
+		memcpy(&buf[0], &data, sizeof(data));
+		len_s -= sizeof(u32);
+		buf += sizeof(u32);
+		from += sizeof(u32);
+	}
+
 	len8 = ALIGN_DOWN(len_s, sizeof(u64));
 	for (i = 0; i < len8; i += sizeof(u64)) {
 		u64 data = idg_nvm_read64(nvm, from + i);