diff options
Diffstat (limited to 'target/linux/generic/backport-5.15/808-v6.2-0008-nvmem-sunxi_sid-Always-use-32-bit-MMIO-reads.patch')
| -rw-r--r-- | target/linux/generic/backport-5.15/808-v6.2-0008-nvmem-sunxi_sid-Always-use-32-bit-MMIO-reads.patch | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/target/linux/generic/backport-5.15/808-v6.2-0008-nvmem-sunxi_sid-Always-use-32-bit-MMIO-reads.patch b/target/linux/generic/backport-5.15/808-v6.2-0008-nvmem-sunxi_sid-Always-use-32-bit-MMIO-reads.patch new file mode 100644 index 0000000000..632b01cb2a --- /dev/null +++ b/target/linux/generic/backport-5.15/808-v6.2-0008-nvmem-sunxi_sid-Always-use-32-bit-MMIO-reads.patch @@ -0,0 +1,55 @@ +From c151d5ed8e8fe0474bd61dce7f2076ca5916c683 Mon Sep 17 00:00:00 2001 +From: Samuel Holland <samuel@sholland.org> +Date: Fri, 27 Jan 2023 10:40:07 +0000 +Subject: [PATCH] nvmem: sunxi_sid: Always use 32-bit MMIO reads + +The SID SRAM on at least some SoCs (A64 and D1) returns different values +when read with bus cycles narrower than 32 bits. This is not immediately +obvious, because memcpy_fromio() uses word-size accesses as long as +enough data is being copied. + +The vendor driver always uses 32-bit MMIO reads, so do the same here. +This is faster than the register-based method, which is currently used +as a workaround on A64. And it fixes the values returned on D1, where +the SRAM method was being used. + +The special case for the last word is needed to maintain .word_size == 1 +for sysfs ABI compatibility, as noted previously in commit de2a3eaea552 +("nvmem: sunxi_sid: Optimize register read-out method"). + +Fixes: 07ae4fde9efa ("nvmem: sunxi_sid: Add support for D1 variant") +Cc: stable@vger.kernel.org +Tested-by: Heiko Stuebner <heiko@sntech.de> +Signed-off-by: Samuel Holland <samuel@sholland.org> +Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> +Link: https://lore.kernel.org/r/20230127104015.23839-3-srinivas.kandagatla@linaro.org +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + drivers/nvmem/sunxi_sid.c | 15 ++++++++++++++- + 1 file changed, 14 insertions(+), 1 deletion(-) + +--- a/drivers/nvmem/sunxi_sid.c ++++ b/drivers/nvmem/sunxi_sid.c +@@ -41,8 +41,21 @@ static int sunxi_sid_read(void *context, + void *val, size_t bytes) + { + struct sunxi_sid *sid = context; ++ u32 word; + +- memcpy_fromio(val, sid->base + sid->value_offset + offset, bytes); ++ /* .stride = 4 so offset is guaranteed to be aligned */ ++ __ioread32_copy(val, sid->base + sid->value_offset + offset, bytes / 4); ++ ++ val += round_down(bytes, 4); ++ offset += round_down(bytes, 4); ++ bytes = bytes % 4; ++ ++ if (!bytes) ++ return 0; ++ ++ /* Handle any trailing bytes */ ++ word = readl_relaxed(sid->base + sid->value_offset + offset); ++ memcpy(val, &word, bytes); + + return 0; + } |