nvmem: qfprom: switch to 4-byte aligned reads

All platforms since Snapdragon 8 Gen1 (SM8450) require using 4-byte
reads to access QFPROM data. While older platforms were more than happy
with 1-byte reads, change the qfprom driver to use 4-byte reads for all
the platforms. Specify stride and word size of 4 bytes. To retain
compatibility with the existing DT and to simplify porting data from
vendor kernels, use fixup_dt_cell_info in order to bump alignment
requirements.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20250411112251.68002-12-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvmem/qfprom.c b/drivers/nvmem/qfprom.c
index 116a39e804c70b4a0374f8ea3ac6ba1dd612109d..a872c640b8c5a558da9ea00e3804c904f8987247 100644 (file)
--- a/drivers/nvmem/qfprom.c
+++ b/drivers/nvmem/qfprom.c
@@ -321,19 +321,32 @@ static int qfprom_reg_read(void *context,
                        unsigned int reg, void *_val, size_t bytes)
 {
        struct qfprom_priv *priv = context;
-       u8 *val = _val;
-       int i = 0, words = bytes;
+       u32 *val = _val;
        void __iomem *base = priv->qfpcorrected;
+       int words = DIV_ROUND_UP(bytes, sizeof(u32));
+       int i;
 
        if (read_raw_data && priv->qfpraw)
                base = priv->qfpraw;
 
-       while (words--)
-               *val++ = readb(base + reg + i++);
+       for (i = 0; i < words; i++)
+               *val++ = readl(base + reg + i * sizeof(u32));
 
        return 0;
 }
 
+/* Align reads to word boundary */
+static void qfprom_fixup_dt_cell_info(struct nvmem_device *nvmem,
+                                     struct nvmem_cell_info *cell)
+{
+       unsigned int byte_offset = cell->offset % sizeof(u32);
+
+       cell->bit_offset += byte_offset * BITS_PER_BYTE;
+       cell->offset -= byte_offset;
+       if (byte_offset && !cell->nbits)
+               cell->nbits = cell->bytes * BITS_PER_BYTE;
+}
+
 static void qfprom_runtime_disable(void *data)
 {
        pm_runtime_disable(data);
@@ -358,10 +371,11 @@ static int qfprom_probe(struct platform_device *pdev)
        struct nvmem_config econfig = {
                .name = "qfprom",
                .add_legacy_fixed_of_cells = true,
-               .stride = 1,
-               .word_size = 1,
+               .stride = 4,
+               .word_size = 4,
                .id = NVMEM_DEVID_AUTO,
                .reg_read = qfprom_reg_read,
+               .fixup_dt_cell_info = qfprom_fixup_dt_cell_info,
        };
        struct device *dev = &pdev->dev;
        struct resource *res;