firmware: qcom_scm: Add bw voting support to the SCM interface

The SMC calls required by remoteproc PAS driver on SM8450 SoCs get a
performance benefit from having a max vote to the crypto->ddr path.
Add support for bandwidth (bw) voting for those SMC calls when the
interconnects property is specified.

Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1653289258-17699-3-git-send-email-quic_sibis@quicinc.com

diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index 4623d29..cdbfe54 100644 (file)
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -7,6 +7,7 @@
 #include <linux/cpumask.h>
 #include <linux/export.h>
 #include <linux/dma-mapping.h>
+#include <linux/interconnect.h>
 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/qcom_scm.h>
@@ -31,8 +32,13 @@ struct qcom_scm {
        struct clk *core_clk;
        struct clk *iface_clk;
        struct clk *bus_clk;
+       struct icc_path *path;
        struct reset_controller_dev reset;
 
+       /* control access to the interconnect path */
+       struct mutex scm_bw_lock;
+       int scm_vote_count;
+
        u64 dload_mode_addr;
 };
 
@@ -99,6 +105,42 @@ static void qcom_scm_clk_disable(void)
        clk_disable_unprepare(__scm->bus_clk);
 }
 
+static int qcom_scm_bw_enable(void)
+{
+       int ret = 0;
+
+       if (!__scm->path)
+               return 0;
+
+       if (IS_ERR(__scm->path))
+               return -EINVAL;
+
+       mutex_lock(&__scm->scm_bw_lock);
+       if (!__scm->scm_vote_count) {
+               ret = icc_set_bw(__scm->path, 0, UINT_MAX);
+               if (ret < 0) {
+                       dev_err(__scm->dev, "failed to set bandwidth request\n");
+                       goto err_bw;
+               }
+       }
+       __scm->scm_vote_count++;
+err_bw:
+       mutex_unlock(&__scm->scm_bw_lock);
+
+       return ret;
+}
+
+static void qcom_scm_bw_disable(void)
+{
+       if (IS_ERR_OR_NULL(__scm->path))
+               return;
+
+       mutex_lock(&__scm->scm_bw_lock);
+       if (__scm->scm_vote_count-- == 1)
+               icc_set_bw(__scm->path, 0, 0);
+       mutex_unlock(&__scm->scm_bw_lock);
+}
+
 enum qcom_scm_convention qcom_scm_convention = SMC_CONVENTION_UNKNOWN;
 static DEFINE_SPINLOCK(scm_query_lock);
 
@@ -444,10 +486,15 @@ int qcom_scm_pas_init_image(u32 peripheral, const void *metadata, size_t size,
        if (ret)
                goto out;
 
+       ret = qcom_scm_bw_enable();
+       if (ret)
+               return ret;
+
        desc.args[1] = mdata_phys;
 
        ret = qcom_scm_call(__scm->dev, &desc, &res);
 
+       qcom_scm_bw_disable();
        qcom_scm_clk_disable();
 
 out:
@@ -507,7 +554,12 @@ int qcom_scm_pas_mem_setup(u32 peripheral, phys_addr_t addr, phys_addr_t size)
        if (ret)
                return ret;
 
+       ret = qcom_scm_bw_enable();
+       if (ret)
+               return ret;
+
        ret = qcom_scm_call(__scm->dev, &desc, &res);
+       qcom_scm_bw_disable();
        qcom_scm_clk_disable();
 
        return ret ? : res.result[0];
@@ -537,7 +589,12 @@ int qcom_scm_pas_auth_and_reset(u32 peripheral)
        if (ret)
                return ret;
 
+       ret = qcom_scm_bw_enable();
+       if (ret)
+               return ret;
+
        ret = qcom_scm_call(__scm->dev, &desc, &res);
+       qcom_scm_bw_disable();
        qcom_scm_clk_disable();
 
        return ret ? : res.result[0];
@@ -566,8 +623,13 @@ int qcom_scm_pas_shutdown(u32 peripheral)
        if (ret)
                return ret;
 
+       ret = qcom_scm_bw_enable();
+       if (ret)
+               return ret;
+
        ret = qcom_scm_call(__scm->dev, &desc, &res);
 
+       qcom_scm_bw_disable();
        qcom_scm_clk_disable();
 
        return ret ? : res.result[0];
@@ -1277,8 +1339,15 @@ static int qcom_scm_probe(struct platform_device *pdev)
        if (ret < 0)
                return ret;
 
+       mutex_init(&scm->scm_bw_lock);
+
        clks = (unsigned long)of_device_get_match_data(&pdev->dev);
 
+       scm->path = devm_of_icc_get(&pdev->dev, NULL);
+       if (IS_ERR(scm->path))
+               return dev_err_probe(&pdev->dev, PTR_ERR(scm->path),
+                                    "failed to acquire interconnect path\n");
+
        scm->core_clk = devm_clk_get(&pdev->dev, "core");
        if (IS_ERR(scm->core_clk)) {
                if (PTR_ERR(scm->core_clk) == -EPROBE_DEFER)