soc: ti: K2G: provide APIs to support driver probe deferral

This patch provide APIs to allow client drivers to support
probe deferral. On K2G SoC, devices can be probed only
after the ti_sci_pm_domains driver is probed and ready.
As drivers may get probed at different order, any driver
that depends on knav dma and qmss drivers, for example
netcp network driver, needs to defer probe until
knav devices are probed and ready to service. To do this,
add an API to query the device ready status from the knav
dma and qmss devices.

Signed-off-by: Murali Karicheri <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/soc/ti/knav_dma.c

···
 
 static struct knav_dma_pool_device *kdev;
 
+static bool device_ready;
+bool knav_dma_device_ready(void)
+{
+	return device_ready;
+}
+EXPORT_SYMBOL_GPL(knav_dma_device_ready);
+
 static bool check_config(struct knav_dma_chan *chan, struct knav_dma_cfg *cfg)
 {
 	if (!memcmp(&chan->cfg, cfg, sizeof(*cfg)))
···
 	debugfs_create_file("knav_dma", S_IFREG | S_IRUGO, NULL, NULL,
 			    &knav_dma_debug_ops);
 
+	device_ready = true;
 	return ret;
 }
 

drivers/soc/ti/knav_qmss_queue.c

···
  */
 const char *knav_acc_firmwares[] = {"ks2_qmss_pdsp_acc48.bin"};
 
+static bool device_ready;
+bool knav_qmss_device_ready(void)
+{
+	return device_ready;
+}
+EXPORT_SYMBOL_GPL(knav_qmss_device_ready);
+
 /**
  * knav_queue_notify: qmss queue notfier call
  *
···
 
 	debugfs_create_file("qmss", S_IFREG | S_IRUGO, NULL, NULL,
 			    &knav_queue_debug_ops);
+	device_ready = true;
 	return 0;
 
 err:

include/linux/soc/ti/knav_dma.h

···
 void *knav_dma_open_channel(struct device *dev, const char *name,
 				struct knav_dma_cfg *config);
 void knav_dma_close_channel(void *channel);
+int knav_dma_get_flow(void *channel);
+bool knav_dma_device_ready(void);
 #else
 static inline void *knav_dma_open_channel(struct device *dev, const char *name,
 				struct knav_dma_cfg *config)
···
 }
 static inline void knav_dma_close_channel(void *channel)
 {}
+
+static inline int knav_dma_get_flow(void *channel)
+{
+	return -EINVAL;
+}
+
+static inline bool knav_dma_device_ready(void)
+{
+	return false;
+}
 
 #endif
 

include/linux/soc/ti/knav_qmss.h

···
 void *knav_pool_desc_unmap(void *ph, dma_addr_t dma, unsigned dma_sz);
 dma_addr_t knav_pool_desc_virt_to_dma(void *ph, void *virt);
 void *knav_pool_desc_dma_to_virt(void *ph, dma_addr_t dma);
+bool knav_qmss_device_ready(void);
 
 #endif /* __SOC_TI_KNAV_QMSS_H__ */