[PATCH] drivers: Defer probe if firmware is not ready

[Jolly Shah]

From: Rajan Vaja <rajan.vaja@xxxxxxxxxx>

Driver needs ZynqMP firmware interface to call EEMI
APIs. In case firmware is not ready, dependent drivers
should wait until the firmware is ready.

Signed-off-by: Rajan Vaja <rajan.vaja@xxxxxxxxxx>
Signed-off-by: Jolly Shah <jollys@xxxxxxxxxx>
---
 Documentation/xilinx/eemi.txt          |  4 ++--
 drivers/clk/zynqmp/clkc.c              |  4 ++--
 drivers/firmware/xilinx/zynqmp-debug.c |  3 ---
 drivers/firmware/xilinx/zynqmp.c       | 11 ++++++++++-
 drivers/nvmem/zynqmp_nvmem.c           | 10 +++++++---
 drivers/reset/reset-zynqmp.c           |  8 ++++----
 drivers/soc/xilinx/zynqmp_pm_domains.c | 18 ++++++++++--------
 drivers/soc/xilinx/zynqmp_power.c      | 10 ++++++----
 drivers/spi/spi-zynqmp-gqspi.c         |  5 +++++
 include/linux/firmware/xlnx-zynqmp.h   |  2 +-
 10 files changed, 47 insertions(+), 28 deletions(-)

diff --git a/Documentation/xilinx/eemi.txt b/Documentation/xilinx/eemi.txt
index 0ab686c..5f39b4f 100644
--- a/Documentation/xilinx/eemi.txt
+++ b/Documentation/xilinx/eemi.txt
@@ -41,8 +41,8 @@ Example of EEMI ops usage:
 	int ret;
 
 	eemi_ops = zynqmp_pm_get_eemi_ops();
-	if (!eemi_ops)
-		return -ENXIO;
+	if (IS_ERR(eemi_ops))
+		return PTR_ERR(eemi_ops);
 
 	ret = eemi_ops->query_data(qdata, ret_payload);
 
diff --git a/drivers/clk/zynqmp/clkc.c b/drivers/clk/zynqmp/clkc.c
index c13b014..1e34e3e 100644
--- a/drivers/clk/zynqmp/clkc.c
+++ b/drivers/clk/zynqmp/clkc.c
@@ -711,8 +711,8 @@ static int zynqmp_clock_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 
 	eemi_ops = zynqmp_pm_get_eemi_ops();
-	if (!eemi_ops)
-		return -ENXIO;
+	if (IS_ERR(eemi_ops))
+		return PTR_ERR(eemi_ops);
 
 	ret = zynqmp_clk_setup(dev->of_node);
 
diff --git a/drivers/firmware/xilinx/zynqmp-debug.c b/drivers/firmware/xilinx/zynqmp-debug.c
index 2771df6..a3aa76c 100644
--- a/drivers/firmware/xilinx/zynqmp-debug.c
+++ b/drivers/firmware/xilinx/zynqmp-debug.c
@@ -90,9 +90,6 @@ static int process_api_request(u32 pm_id, u64 *pm_api_arg, u32 *pm_api_ret)
 	int ret;
 	struct zynqmp_pm_query_data qdata = {0};
 
-	if (!eemi_ops)
-		return -ENXIO;
-
 	switch (pm_id) {
 	case PM_GET_API_VERSION:
 		ret = eemi_ops->get_api_version(&pm_api_version);
diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
index 98f9361..87a1d63 100644
--- a/drivers/firmware/xilinx/zynqmp.c
+++ b/drivers/firmware/xilinx/zynqmp.c
@@ -24,6 +24,8 @@
 #include <linux/firmware/xlnx-zynqmp.h>
 #include "zynqmp-debug.h"
 
+static const struct zynqmp_eemi_ops *eemi_ops_tbl;
+
 static const struct mfd_cell firmware_devs[] = {
 	{
 		.name = "zynqmp_power_controller",
@@ -649,7 +651,11 @@ static const struct zynqmp_eemi_ops eemi_ops = {
  */
 const struct zynqmp_eemi_ops *zynqmp_pm_get_eemi_ops(void)
 {
-	return &eemi_ops;
+	if (eemi_ops_tbl)
+		return eemi_ops_tbl;
+	else
+		return ERR_PTR(-EPROBE_DEFER);
+
 }
 EXPORT_SYMBOL_GPL(zynqmp_pm_get_eemi_ops);
 
@@ -694,6 +700,9 @@ static int zynqmp_firmware_probe(struct platform_device *pdev)
 	pr_info("%s Trustzone version v%d.%d\n", __func__,
 		pm_tz_version >> 16, pm_tz_version & 0xFFFF);
 
+	/* Assign eemi_ops_table */
+	eemi_ops_tbl = &eemi_ops;
+
 	zynqmp_pm_api_debugfs_init();
 
 	ret = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_NONE, firmware_devs,
diff --git a/drivers/nvmem/zynqmp_nvmem.c b/drivers/nvmem/zynqmp_nvmem.c
index 490c8fc..5893543 100644
--- a/drivers/nvmem/zynqmp_nvmem.c
+++ b/drivers/nvmem/zynqmp_nvmem.c
@@ -16,6 +16,8 @@ struct zynqmp_nvmem_data {
 	struct nvmem_device *nvmem;
 };
 
+static const struct zynqmp_eemi_ops *eemi_ops;
+
 static int zynqmp_nvmem_read(void *context, unsigned int offset,
 			     void *val, size_t bytes)
 {
@@ -23,9 +25,7 @@ static int zynqmp_nvmem_read(void *context, unsigned int offset,
 	int idcode, version;
 	struct zynqmp_nvmem_data *priv = context;
 
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
-
-	if (!eemi_ops || !eemi_ops->get_chipid)
+	if (!eemi_ops->get_chipid)
 		return -ENXIO;
 
 	ret = eemi_ops->get_chipid(&idcode, &version);
@@ -61,6 +61,10 @@ static int zynqmp_nvmem_probe(struct platform_device *pdev)
 	if (!priv)
 		return -ENOMEM;
 
+	eemi_ops = zynqmp_pm_get_eemi_ops();
+	if (IS_ERR(eemi_ops))
+		return PTR_ERR(eemi_ops);
+
 	priv->dev = dev;
 	econfig.dev = dev;
 	econfig.reg_read = zynqmp_nvmem_read;
diff --git a/drivers/reset/reset-zynqmp.c b/drivers/reset/reset-zynqmp.c
index 2ef1f13..99e75d9 100644
--- a/drivers/reset/reset-zynqmp.c
+++ b/drivers/reset/reset-zynqmp.c
@@ -79,11 +79,11 @@ static int zynqmp_reset_probe(struct platform_device *pdev)
 	if (!priv)
 		return -ENOMEM;
 
-	platform_set_drvdata(pdev, priv);
-
 	priv->eemi_ops = zynqmp_pm_get_eemi_ops();
-	if (!priv->eemi_ops)
-		return -ENXIO;
+	if (IS_ERR(priv->eemi_ops))
+		return PTR_ERR(priv->eemi_ops);
+
+	platform_set_drvdata(pdev, priv);
 
 	priv->rcdev.ops = &zynqmp_reset_ops;
 	priv->rcdev.owner = THIS_MODULE;
diff --git a/drivers/soc/xilinx/zynqmp_pm_domains.c b/drivers/soc/xilinx/zynqmp_pm_domains.c
index 354d256..600f57c 100644
--- a/drivers/soc/xilinx/zynqmp_pm_domains.c
+++ b/drivers/soc/xilinx/zynqmp_pm_domains.c
@@ -23,6 +23,8 @@
 /* Flag stating if PM nodes mapped to the PM domain has been requested */
 #define ZYNQMP_PM_DOMAIN_REQUESTED	BIT(0)
 
+static const struct zynqmp_eemi_ops *eemi_ops;
+
 /**
  * struct zynqmp_pm_domain - Wrapper around struct generic_pm_domain
  * @gpd:		Generic power domain
@@ -71,9 +73,8 @@ static int zynqmp_gpd_power_on(struct generic_pm_domain *domain)
 {
 	int ret;
 	struct zynqmp_pm_domain *pd;
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
 
-	if (!eemi_ops || !eemi_ops->set_requirement)
+	if (!eemi_ops->set_requirement)
 		return -ENXIO;
 
 	pd = container_of(domain, struct zynqmp_pm_domain, gpd);
@@ -107,9 +108,8 @@ static int zynqmp_gpd_power_off(struct generic_pm_domain *domain)
 	struct zynqmp_pm_domain *pd;
 	u32 capabilities = 0;
 	bool may_wakeup;
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
 
-	if (!eemi_ops || !eemi_ops->set_requirement)
+	if (!eemi_ops->set_requirement)
 		return -ENXIO;
 
 	pd = container_of(domain, struct zynqmp_pm_domain, gpd);
@@ -160,9 +160,8 @@ static int zynqmp_gpd_attach_dev(struct generic_pm_domain *domain,
 {
 	int ret;
 	struct zynqmp_pm_domain *pd;
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
 
-	if (!eemi_ops || !eemi_ops->request_node)
+	if (!eemi_ops->request_node)
 		return -ENXIO;
 
 	pd = container_of(domain, struct zynqmp_pm_domain, gpd);
@@ -197,9 +196,8 @@ static void zynqmp_gpd_detach_dev(struct generic_pm_domain *domain,
 {
 	int ret;
 	struct zynqmp_pm_domain *pd;
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
 
-	if (!eemi_ops || !eemi_ops->release_node)
+	if (!eemi_ops->release_node)
 		return;
 
 	pd = container_of(domain, struct zynqmp_pm_domain, gpd);
@@ -266,6 +264,10 @@ static int zynqmp_gpd_probe(struct platform_device *pdev)
 	struct zynqmp_pm_domain *pd;
 	struct device *dev = &pdev->dev;
 
+	eemi_ops = zynqmp_pm_get_eemi_ops();
+	if (IS_ERR(eemi_ops))
+		return PTR_ERR(eemi_ops);
+
 	pd = devm_kcalloc(dev, ZYNQMP_NUM_DOMAINS, sizeof(*pd), GFP_KERNEL);
 	if (!pd)
 		return -ENOMEM;
diff --git a/drivers/soc/xilinx/zynqmp_power.c b/drivers/soc/xilinx/zynqmp_power.c
index 771cb59..1b9d144 100644
--- a/drivers/soc/xilinx/zynqmp_power.c
+++ b/drivers/soc/xilinx/zynqmp_power.c
@@ -31,6 +31,7 @@ static const char *const suspend_modes[] = {
 };
 
 static enum pm_suspend_mode suspend_mode = PM_SUSPEND_MODE_STD;
+static const struct zynqmp_eemi_ops *eemi_ops;
 
 enum pm_api_cb_id {
 	PM_INIT_SUSPEND_CB = 30,
@@ -92,9 +93,8 @@ static ssize_t suspend_mode_store(struct device *dev,
 				  const char *buf, size_t count)
 {
 	int md, ret = -EINVAL;
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
 
-	if (!eemi_ops || !eemi_ops->set_suspend_mode)
+	if (!eemi_ops->set_suspend_mode)
 		return ret;
 
 	for (md = PM_SUSPEND_MODE_FIRST; md < ARRAY_SIZE(suspend_modes); md++)
@@ -120,9 +120,11 @@ static int zynqmp_pm_probe(struct platform_device *pdev)
 	int ret, irq;
 	u32 pm_api_version;
 
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
+	eemi_ops = zynqmp_pm_get_eemi_ops();
+	if (IS_ERR(eemi_ops))
+		return PTR_ERR(eemi_ops);
 
-	if (!eemi_ops || !eemi_ops->get_api_version || !eemi_ops->init_finalize)
+	if (!eemi_ops->get_api_version || !eemi_ops->init_finalize)
 		return -ENXIO;
 
 	eemi_ops->init_finalize();
diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
index 9f83e1b..d07b6f9 100644
--- a/drivers/spi/spi-zynqmp-gqspi.c
+++ b/drivers/spi/spi-zynqmp-gqspi.c
@@ -138,6 +138,7 @@
 
 #define SPI_AUTOSUSPEND_TIMEOUT		3000
 enum mode_type {GQSPI_MODE_IO, GQSPI_MODE_DMA};
+static const struct zynqmp_eemi_ops *eemi_ops;
 
 /**
  * struct zynqmp_qspi - Defines qspi driver instance
@@ -1021,6 +1022,10 @@ static int zynqmp_qspi_probe(struct platform_device *pdev)
 	struct resource *res;
 	struct device *dev = &pdev->dev;
 
+	eemi_ops = zynqmp_pm_get_eemi_ops();
+	if (IS_ERR(eemi_ops))
+		return PTR_ERR(eemi_ops);
+
 	master = spi_alloc_master(&pdev->dev, sizeof(*xqspi));
 	if (!master)
 		return -ENOMEM;
diff --git a/include/linux/firmware/xlnx-zynqmp.h b/include/linux/firmware/xlnx-zynqmp.h
index 642dab1..3533ee5 100644
--- a/include/linux/firmware/xlnx-zynqmp.h
+++ b/include/linux/firmware/xlnx-zynqmp.h
@@ -293,7 +293,7 @@ const struct zynqmp_eemi_ops *zynqmp_pm_get_eemi_ops(void);
 #else
 static inline struct zynqmp_eemi_ops *zynqmp_pm_get_eemi_ops(void)
 {
-	return NULL;
+	return ERR_PTR(-ENODEV);
 }
 #endif
 
-- 
2.7.4