IB/hfi1: Use built-in i2c bit-shift bus adapter

Use built-in i2c bit-shift bus adapter to control the
i2c busses on the chip.

Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Easwar Hariharan <easwar.hariharan@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/hfi1/Kconfig

 config INFINIBAND_HFI1
 	tristate "Intel OPA Gen1 support"
-	depends on X86_64 && INFINIBAND_RDMAVT
+	depends on X86_64 && INFINIBAND_RDMAVT && I2C
 	select MMU_NOTIFIER
 	select CRC32
+	select I2C_ALGOBIT
 	default m
 	---help---
 	This is a low-level driver for Intel OPA Gen1 adapter.

drivers/infiniband/hw/hfi1/chip.c

@@ -14165,6 +14165,11 @@ static int init_asic_data(struct hfi1_devdata *dd)
 	}
 	dd->asic_data->dds[dd->hfi1_id] = dd; /* self back-pointer */
 	spin_unlock_irqrestore(&hfi1_devs_lock, flags);
+
+	/* first one through - set up i2c devices */
+	if (!peer)
+		ret = set_up_i2c(dd, dd->asic_data);
+
 	return ret;
 }
 

drivers/infiniband/hw/hfi1/hfi.h

@@ -62,6 +62,8 @@
 #include <linux/cdev.h>
 #include <linux/delay.h>
 #include <linux/kthread.h>
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
 #include <rdma/rdma_vt.h>
 
 #include "chip_registers.h"
@@ -805,10 +807,19 @@ struct hfi1_temp {
 	u8 triggers;      /* temperature triggers */
 };
 
+struct hfi1_i2c_bus {
+	struct hfi1_devdata *controlling_dd; /* current controlling device */
+	struct i2c_adapter adapter;	/* bus details */
+	struct i2c_algo_bit_data algo;	/* bus algorithm details */
+	int num;			/* bus number, 0 or 1 */
+};
+
 /* common data between shared ASIC HFIs */
 struct hfi1_asic_data {
 	struct hfi1_devdata *dds[2];	/* back pointers */
 	struct mutex asic_resource_mutex;
+	struct hfi1_i2c_bus *i2c_bus0;
+	struct hfi1_i2c_bus *i2c_bus1;
 };
 
 /* device data struct now contains only "general per-device" info.

drivers/infiniband/hw/hfi1/init.c

@@ -973,34 +973,45 @@ void hfi1_free_ctxtdata(struct hfi1_devdata *dd, struct hfi1_ctxtdata *rcd)
 
 /*
  * Release our hold on the shared asic data.  If we are the last one,
- * free the structure.  Must be holding hfi1_devs_lock.
+ * return the structure to be finalized outside the lock.  Must be
+ * holding hfi1_devs_lock.
  */
-static void release_asic_data(struct hfi1_devdata *dd)
+static struct hfi1_asic_data *release_asic_data(struct hfi1_devdata *dd)
 {
+	struct hfi1_asic_data *ad;
 	int other;
 
 	if (!dd->asic_data)
-		return;
+		return NULL;
 	dd->asic_data->dds[dd->hfi1_id] = NULL;
 	other = dd->hfi1_id ? 0 : 1;
-	if (!dd->asic_data->dds[other]) {
-		/* we are the last holder, free it */
-		kfree(dd->asic_data);
-	}
+	ad = dd->asic_data;
 	dd->asic_data = NULL;
+	/* return NULL if the other dd still has a link */
+	return ad->dds[other] ? NULL : ad;
+}
+
+static void finalize_asic_data(struct hfi1_devdata *dd,
+			       struct hfi1_asic_data *ad)
+{
+	clean_up_i2c(dd, ad);
+	kfree(ad);
 }
 
 static void __hfi1_free_devdata(struct kobject *kobj)
 {
 	struct hfi1_devdata *dd =
 		container_of(kobj, struct hfi1_devdata, kobj);
+	struct hfi1_asic_data *ad;
 	unsigned long flags;
 
 	spin_lock_irqsave(&hfi1_devs_lock, flags);
 	idr_remove(&hfi1_unit_table, dd->unit);
 	list_del(&dd->list);
-	release_asic_data(dd);
+	ad = release_asic_data(dd);
 	spin_unlock_irqrestore(&hfi1_devs_lock, flags);
+	if (ad)
+		finalize_asic_data(dd, ad);
 	free_platform_config(dd);
 	rcu_barrier(); /* wait for rcu callbacks to complete */
 	free_percpu(dd->int_counter);

drivers/infiniband/hw/hfi1/qsfp.h

@@ -238,3 +238,6 @@ int one_qsfp_write(struct hfi1_pportdata *ppd, u32 target, int addr, void *bp,
 		   int len);
 int one_qsfp_read(struct hfi1_pportdata *ppd, u32 target, int addr, void *bp,
 		  int len);
+struct hfi1_asic_data;
+int set_up_i2c(struct hfi1_devdata *dd, struct hfi1_asic_data *ad);
+void clean_up_i2c(struct hfi1_devdata *dd, struct hfi1_asic_data *ad);