nvmem: rockchip-otp: Handle internal word_size in main reg_read op

Rockchip SoCs RK3576 and RK3588 read data from the OTP using 32-bit
words instead of normal 8-bit bytes. Similar RK3506, RK3528, RK3562 and
RK3568 will read data from OTP using 16-bit words.

The nvmem core stride and word_size cannot fully be used as cells is not
always aligned. Continue to report a stride=1 and word_size=1 in
nvmem_config and instead handle use of SoC specific word_size internally
in the driver.

Move current SoC specific word_size handling from the RK3588 read_reg
operation to the main read_reg operation to help simplify the SoC
specific read_reg operation and allow code reuse in a future RK3568
reg_read operation.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Tested-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Srinivas Kandagatla <srini@kernel.org>
Link: https://patch.msgid.link/20260327131751.3026030-7-srini@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvmem/rockchip-otp.c b/drivers/nvmem/rockchip-otp.c
index d88f12c53242643c41da4430be4c7c57cd43b6b8..45bbb6147fb773d9a25fa075bc4c6f851a6f274c 100644 (file)
--- a/drivers/nvmem/rockchip-otp.c
+++ b/drivers/nvmem/rockchip-otp.c
@@ -59,7 +59,6 @@
 #define RK3588_OTPC_AUTO_EN            0x08
 #define RK3588_OTPC_INT_ST             0x84
 #define RK3588_OTPC_DOUT0              0x20
-#define RK3588_NBYTES                  4
 #define RK3588_BURST_NUM               1
 #define RK3588_BURST_SHIFT             8
 #define RK3588_ADDR_SHIFT              16
@@ -69,6 +68,7 @@
 struct rockchip_data {
        int size;
        int read_offset;
+       int word_size;
        const char * const *clks;
        int num_clks;
        nvmem_reg_read_t reg_read;
@@ -185,48 +185,28 @@ read_end:
 }
 
 static int rk3588_otp_read(void *context, unsigned int offset,
-                          void *val, size_t bytes)
+                          void *val, size_t count)
 {
        struct rockchip_otp *otp = context;
-       unsigned int addr_start, addr_end, addr_len;
-       int ret, i = 0;
-       u32 data;
-       u8 *buf;
-
-       addr_start = round_down(offset, RK3588_NBYTES) / RK3588_NBYTES;
-       addr_end = round_up(offset + bytes, RK3588_NBYTES) / RK3588_NBYTES;
-       addr_len = addr_end - addr_start;
-       addr_start += otp->data->read_offset / RK3588_NBYTES;
-
-       buf = kzalloc(array_size(addr_len, RK3588_NBYTES), GFP_KERNEL);
-       if (!buf)
-               return -ENOMEM;
+       u32 *buf = val;
+       int ret;
 
-       while (addr_len--) {
-               writel((addr_start << RK3588_ADDR_SHIFT) |
+       while (count--) {
+               writel((offset++ << RK3588_ADDR_SHIFT) |
                       (RK3588_BURST_NUM << RK3588_BURST_SHIFT),
                       otp->base + RK3588_OTPC_AUTO_CTRL);
                writel(RK3588_AUTO_EN, otp->base + RK3588_OTPC_AUTO_EN);
 
                ret = rockchip_otp_wait_status(otp, RK3588_OTPC_INT_ST,
                                               RK3588_RD_DONE);
-               if (ret < 0) {
+               if (ret) {
                        dev_err(otp->dev, "timeout during read setup\n");
-                       goto read_end;
+                       return ret;
                }
 
-               data = readl(otp->base + RK3588_OTPC_DOUT0);
-               memcpy(&buf[i], &data, RK3588_NBYTES);
-
-               i += RK3588_NBYTES;
-               addr_start++;
+               *buf++ = readl(otp->base + RK3588_OTPC_DOUT0);
        }
 
-       memcpy(val, buf + offset % RK3588_NBYTES, bytes);
-
-read_end:
-       kfree(buf);
-
        return ret;
 }
 
@@ -234,7 +214,7 @@ static int rockchip_otp_read(void *context, unsigned int offset,
                             void *val, size_t bytes)
 {
        struct rockchip_otp *otp = context;
-       int ret;
+       int ret, word_size;
 
        if (!otp->data || !otp->data->reg_read)
                return -EINVAL;
@@ -245,8 +225,34 @@ static int rockchip_otp_read(void *context, unsigned int offset,
                return ret;
        }
 
-       ret = otp->data->reg_read(context, offset, val, bytes);
+       offset += otp->data->read_offset;
+       word_size = otp->data->word_size;
+
+       if (word_size > 1) {
+               unsigned int addr_start, addr_end;
+               size_t count;
+               u8 *buf;
+
+               addr_start = offset / word_size;
+               addr_end = DIV_ROUND_UP(offset + bytes, word_size);
+               count = addr_end - addr_start;
+
+               buf = kzalloc(array_size(count, word_size), GFP_KERNEL);
+               if (!buf) {
+                       ret = -ENOMEM;
+                       goto err;
+               }
+
+               ret = otp->data->reg_read(context, addr_start, buf, count);
+               if (!ret)
+                       memcpy(val, buf + (offset % word_size), bytes);
+
+               kfree(buf);
+       } else {
+               ret = otp->data->reg_read(context, offset, val, bytes);
+       }
 
+err:
        clk_bulk_disable_unprepare(otp->data->num_clks, otp->clks);
 
        return ret;
@@ -259,7 +265,7 @@ static struct nvmem_config otp_config = {
        .type = NVMEM_TYPE_OTP,
        .read_only = true,
        .stride = 1,
-       .word_size = 1,
+       .word_size = sizeof(u8),
        .reg_read = rockchip_otp_read,
 };
 
@@ -277,6 +283,7 @@ static const struct rockchip_data px30_data = {
 static const struct rockchip_data rk3576_data = {
        .size = 0x100,
        .read_offset = 0x700,
+       .word_size = sizeof(u32),
        .clks = px30_otp_clocks,
        .num_clks = ARRAY_SIZE(px30_otp_clocks),
        .reg_read = rk3588_otp_read,
@@ -289,6 +296,7 @@ static const char * const rk3588_otp_clocks[] = {
 static const struct rockchip_data rk3588_data = {
        .size = 0x400,
        .read_offset = 0xc00,
+       .word_size = sizeof(u32),
        .clks = rk3588_otp_clocks,
        .num_clks = ARRAY_SIZE(rk3588_otp_clocks),
        .reg_read = rk3588_otp_read,