firmware: samsung: acpm: Make acpm_ops const and access via pointer

Replace the embedded `struct acpm_ops` inside `struct acpm_handle` with
a pointer to a `const struct acpm_ops`.

Previously, the operations structure was embedded directly within the
handle and populated dynamically at runtime via `acpm_setup_ops()`.
This resulted in mutable function pointers and unnecessary per-instance
memory overhead.

By defining `exynos_acpm_driver_ops` statically as a `const` structure,
the function pointers are now safely housed in the read-only `.rodata`
section. This improves security by preventing function pointer
overwrites, saves memory, and slightly reduces initialization overhead
in `acpm_probe()`.

Consequently, update all consumer drivers (clk, mfd) to access the
operations via the new pointer indirection (`->ops->`). Finally, fix
the previously empty kernel-doc description for the ops member to
reflect its new pointer nature.

Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
Link: https://patch.msgid.link/20260515-acpm-tmu-helpers-v2-4-8ca011d5a965@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

diff --git a/drivers/clk/samsung/clk-acpm.c b/drivers/clk/samsung/clk-acpm.c
index 93667777094c626a058a13b5024befc70c41b276..953ca8d5720a3e97792e122f3b2b0f5127266820 100644 (file)
--- a/drivers/clk/samsung/clk-acpm.c
+++ b/drivers/clk/samsung/clk-acpm.c
@@ -68,8 +68,8 @@ static unsigned long acpm_clk_recalc_rate(struct clk_hw *hw,
 {
        struct acpm_clk *clk = to_acpm_clk(hw);
 
-       return clk->handle->ops.dvfs.get_rate(clk->handle, clk->mbox_chan_id,
-                                             clk->id);
+       return clk->handle->ops->dvfs.get_rate(clk->handle, clk->mbox_chan_id,
+                                              clk->id);
 }
 
 static int acpm_clk_determine_rate(struct clk_hw *hw,
@@ -89,8 +89,8 @@ static int acpm_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 {
        struct acpm_clk *clk = to_acpm_clk(hw);
 
-       return clk->handle->ops.dvfs.set_rate(clk->handle, clk->mbox_chan_id,
-                                             clk->id, rate);
+       return clk->handle->ops->dvfs.set_rate(clk->handle, clk->mbox_chan_id,
+                                              clk->id, rate);
 }
 
 static const struct clk_ops acpm_clk_ops = {

diff --git a/drivers/firmware/samsung/exynos-acpm.c b/drivers/firmware/samsung/exynos-acpm.c
index bd2bfd8d85129992331ed5ffd189e12cc6731608..a1f73cc7cc8fa2d24284aafa2c0b1571df09a003 100644 (file)
--- a/drivers/firmware/samsung/exynos-acpm.c
+++ b/drivers/firmware/samsung/exynos-acpm.c
@@ -666,30 +666,26 @@ static int acpm_channels_init(struct acpm_info *acpm)
        return 0;
 }
 
-/**
- * acpm_setup_ops() - setup the operations structures.
- * @acpm:      pointer to the driver data.
- */
-static void acpm_setup_ops(struct acpm_info *acpm)
-{
-       struct acpm_dvfs_ops *dvfs_ops = &acpm->handle.ops.dvfs;
-       struct acpm_pmic_ops *pmic_ops = &acpm->handle.ops.pmic;
-
-       dvfs_ops->set_rate = acpm_dvfs_set_rate;
-       dvfs_ops->get_rate = acpm_dvfs_get_rate;
-
-       pmic_ops->read_reg = acpm_pmic_read_reg;
-       pmic_ops->bulk_read = acpm_pmic_bulk_read;
-       pmic_ops->write_reg = acpm_pmic_write_reg;
-       pmic_ops->bulk_write = acpm_pmic_bulk_write;
-       pmic_ops->update_reg = acpm_pmic_update_reg;
-}
-
 static void acpm_clk_pdev_unregister(void *data)
 {
        platform_device_unregister(data);
 }
 
+static const struct acpm_ops exynos_acpm_driver_ops = {
+       .dvfs = {
+               .set_rate = acpm_dvfs_set_rate,
+               .get_rate = acpm_dvfs_get_rate,
+       },
+
+       .pmic = {
+               .read_reg = acpm_pmic_read_reg,
+               .bulk_read = acpm_pmic_bulk_read,
+               .write_reg = acpm_pmic_write_reg,
+               .bulk_write = acpm_pmic_bulk_write,
+               .update_reg = acpm_pmic_update_reg,
+       },
+};
+
 static int acpm_probe(struct platform_device *pdev)
 {
        const struct acpm_match_data *match_data;
@@ -730,7 +726,7 @@ static int acpm_probe(struct platform_device *pdev)
        if (ret)
                return ret;
 
-       acpm_setup_ops(acpm);
+       acpm->handle.ops = &exynos_acpm_driver_ops;
 
        platform_set_drvdata(pdev, acpm);
 

diff --git a/drivers/mfd/sec-acpm.c b/drivers/mfd/sec-acpm.c
index 9e15b260b8dfd8a02fc92b6083de1a1ff41506ed..3397d13d3b7f443478824dadd59e4a7ec5196d3d 100644 (file)
--- a/drivers/mfd/sec-acpm.c
+++ b/drivers/mfd/sec-acpm.c
@@ -391,7 +391,7 @@ static int sec_pmic_acpm_bus_write(void *context, const void *data,
 {
        struct sec_pmic_acpm_bus_context *ctx = context;
        struct acpm_handle *acpm = ctx->shared->acpm;
-       const struct acpm_pmic_ops *pmic_ops = &acpm->ops.pmic;
+       const struct acpm_pmic_ops *pmic_ops = &acpm->ops->pmic;
        size_t val_count = count - BITS_TO_BYTES(ACPM_ADDR_BITS);
        const u8 *d = data;
        const u8 *vals = &d[BITS_TO_BYTES(ACPM_ADDR_BITS)];
@@ -411,7 +411,7 @@ static int sec_pmic_acpm_bus_read(void *context, const void *reg_buf, size_t reg
 {
        struct sec_pmic_acpm_bus_context *ctx = context;
        struct acpm_handle *acpm = ctx->shared->acpm;
-       const struct acpm_pmic_ops *pmic_ops = &acpm->ops.pmic;
+       const struct acpm_pmic_ops *pmic_ops = &acpm->ops->pmic;
        const u8 *r = reg_buf;
        u8 reg;
 
@@ -430,7 +430,7 @@ static int sec_pmic_acpm_bus_reg_update_bits(void *context, unsigned int reg, un
 {
        struct sec_pmic_acpm_bus_context *ctx = context;
        struct acpm_handle *acpm = ctx->shared->acpm;
-       const struct acpm_pmic_ops *pmic_ops = &acpm->ops.pmic;
+       const struct acpm_pmic_ops *pmic_ops = &acpm->ops->pmic;
 
        return pmic_ops->update_reg(acpm, ctx->shared->acpm_chan_id, ctx->type, reg & 0xff,
                                    ctx->shared->speedy_channel, val, mask);

diff --git a/include/linux/firmware/samsung/exynos-acpm-protocol.h b/include/linux/firmware/samsung/exynos-acpm-protocol.h
index 62a3eb450067d2b678dad2d8c070245058c78a93..e13d9ac73ff6092ddbf81aed9fec76f2993c7512 100644 (file)
--- a/include/linux/firmware/samsung/exynos-acpm-protocol.h
+++ b/include/linux/firmware/samsung/exynos-acpm-protocol.h
@@ -41,10 +41,10 @@ struct acpm_ops {
 
 /**
  * struct acpm_handle - Reference to an initialized protocol instance
- * @ops:
+ * @ops:       pointer to the constant ACPM protocol operations.
  */
 struct acpm_handle {
-       struct acpm_ops ops;
+       const struct acpm_ops *ops;
 };
 
 struct device;