Re: [PATCH v5 13/17] firmware: qcom_scm: provide a read-modify-write function

On 9/11/2023 1:38 PM, Kathiravan Thirumoorthy wrote:

On 9/10/2023 1:46 AM, Mukesh Ojha wrote:

quoted

It was realized by Srinivas K. that there is a need of
read-modify-write scm exported function so that it can
be used by multiple clients.

Let's introduce qcom_scm_io_update_field() which masks
out the bits and write the passed value to that
bit-offset. Subsequent patch will use this function.

Suggested-by: Srinivas Kandagatla <redacted>
Signed-off-by: Mukesh Ojha <redacted>
---

Validated this change on IPQ9574 and IPQ53332 and system is entering 
into the download mode.

Tested-by: Kathiravan Thirumoorthy <redacted> # 
IP9574 and IPQ5332

Couple of typos. Apologize...

Validated this change on IPQ9574 and IPQ5332 and system is entering into 
the download mode.

Tested-by: Kathiravan Thirumoorthy <redacted> # IPQ9574 
and IPQ5332

quoted

  drivers/firmware/qcom_scm.c            | 20 ++++++++++++++++++++
  include/linux/firmware/qcom/qcom_scm.h |  2 ++
  2 files changed, 22 insertions(+)

diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index fde33acd46b7..5ea8fc4fd4e8 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c

@@ -78,6 +78,7 @@ static const char * const 

qcom_scm_convention_names[] = {
  };
    static struct qcom_scm *__scm;
+static DEFINE_SPINLOCK(lock);
    static int qcom_scm_clk_enable(void)
  {

@@ -407,6 +408,25 @@ int qcom_scm_set_remote_state(u32 state, u32 id)

  }
  EXPORT_SYMBOL(qcom_scm_set_remote_state);
  +int qcom_scm_io_update_field(phys_addr_t addr, unsigned int mask, 
unsigned int val)
+{
+    unsigned int old, new;
+    int ret;
+
+    spin_lock(&lock);
+    ret = qcom_scm_io_readl(addr, &old);
+    if (ret)
+        goto unlock;
+
+    new = (old & ~mask) | (val & mask);
+
+    ret = qcom_scm_io_writel(addr, new);
+unlock:
+    spin_unlock(&lock);
+    return ret;
+}
+EXPORT_SYMBOL_GPL(qcom_scm_io_update_field);
+
  static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
  {
      struct qcom_scm_desc desc = {

diff --git a/include/linux/firmware/qcom/qcom_scm.h 

b/include/linux/firmware/qcom/qcom_scm.h
index 250ea4efb7cb..ca41e4eb33ad 100644

--- a/include/linux/firmware/qcom/qcom_scm.h
+++ b/include/linux/firmware/qcom/qcom_scm.h

@@ -84,6 +84,8 @@ extern bool qcom_scm_pas_supported(u32 peripheral);

    extern int qcom_scm_io_readl(phys_addr_t addr, unsigned int *val);
  extern int qcom_scm_io_writel(phys_addr_t addr, unsigned int val);
+extern int qcom_scm_io_update_field(phys_addr_t addr, unsigned int 
mask,
+                    unsigned int val);
    extern bool qcom_scm_restore_sec_cfg_available(void);
  extern int qcom_scm_restore_sec_cfg(u32 device_id, u32 spare);

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