i2c: Move tpm i2c wrapper code into core

The TPM code has a wrapper around the main i2c API to allow synchronous use.

Move it into core/i2c.c so it can be used by other possible users. In
particular, a future patch will use this to drive OpenCAPI device resets
during boot time.

Cc: Claudio Carvalho <cclaudio@linux.vnet.ibm.com>
Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

1 files changed, 107 insertions, 0 deletions

diff --git a/core/i2c.c b/core/i2c.c
index c164624..d4311c2 100644
--- a/core/i2c.c
+++ b/core/i2c.c
@@ -19,6 +19,7 @@
 #include <opal.h>
 #include <device.h>
 #include <opal-msg.h>
+#include <timebase.h>
 
 static LIST_HEAD(i2c_bus_list);
 
@@ -134,4 +135,110 @@ static int opal_i2c_request(uint64_t async_token, uint32_t bus_id,
 }
 opal_call(OPAL_I2C_REQUEST, opal_i2c_request, 3);
 
+#define MAX_NACK_RETRIES		 2
+#define REQ_COMPLETE_POLLING		 5  /* Check if req is complete
+					       in 5ms interval */
 
+struct i2c_sync_userdata {
+	int rc;
+	bool done;
+};
+
+static void i2c_sync_request_complete(int rc, struct i2c_request *req)
+{
+	struct i2c_sync_userdata *ud = req->user_data;
+	ud->rc = rc;
+	ud->done = true;
+}
+
+/**
+ * i2c_request_send - send request to i2c bus synchronously
+ * @bus_id: i2c bus id
+ * @dev_addr: address of the device
+ * @read_write: SMBUS_READ or SMBUS_WRITE
+ * @offset: any of the I2C interface offset defined
+ * @offset_bytes: offset size in bytes
+ * @buf: data to be read or written
+ * @buflen: buf length
+ * @timeout: request timeout in milliseconds
+ *
+ * Send an I2C request to a device synchronously
+ *
+ * Returns: Zero on success otherwise a negative error code
+ */
+int i2c_request_send(int bus_id, int dev_addr, int read_write,
+		     uint32_t offset, uint32_t offset_bytes, void* buf,
+		     size_t buflen, int timeout)
+{
+	int rc, waited, retries;
+	struct i2c_request *req;
+	struct i2c_bus *bus;
+	uint64_t time_to_wait = 0;
+	struct i2c_sync_userdata ud;
+
+	bus = i2c_find_bus_by_id(bus_id);
+	if (!bus) {
+		/**
+		 * @fwts-label I2CInvalidBusID
+		 * @fwts-advice i2c_request_send was passed an invalid bus
+		 * ID. This indicates a bug.
+		 */
+		prlog(PR_ERR, "I2C: Invalid bus_id=%x\n", bus_id);
+		return OPAL_PARAMETER;
+	}
+
+	req = i2c_alloc_req(bus);
+	if (!req) {
+		/**
+		 * @fwts-label I2CAllocationFailed
+		 * @fwts-advice OPAL failed to allocate memory for an
+		 * i2c_request. This points to an OPAL bug as OPAL run out of
+		 * memory and this should never happen.
+		 */
+		prlog(PR_ERR, "I2C: i2c_alloc_req failed\n");
+		return OPAL_INTERNAL_ERROR;
+	}
+
+	req->dev_addr   = dev_addr;
+	req->op         = read_write;
+	req->offset     = offset;
+	req->offset_bytes = offset_bytes;
+	req->rw_buf     = (void*) buf;
+	req->rw_len     = buflen;
+	req->completion = i2c_sync_request_complete;
+	ud.done = false;
+	req->user_data = &ud;
+
+	for (retries = 0; retries <= MAX_NACK_RETRIES; retries++) {
+		waited = 0;
+		i2c_set_req_timeout(req, timeout);
+		i2c_queue_req(req);
+
+		do {
+			time_to_wait = i2c_run_req(req);
+			if (!time_to_wait)
+				time_to_wait = REQ_COMPLETE_POLLING;
+			time_wait(time_to_wait);
+			waited += time_to_wait;
+		} while (!ud.done);
+
+		rc = ud.rc;
+
+		if (rc == OPAL_I2C_NACK_RCVD)
+			continue;
+		else
+			/* error or success */
+			break;
+	}
+
+	prlog(PR_DEBUG, "I2C: %s req op=%x offset=%x buf=%016llx buflen=%d "
+	      "delay=%lu/%d rc=%d\n",
+	      (rc) ? "!!!!" : "----", req->op, req->offset,
+	      *(uint64_t*) buf, req->rw_len, tb_to_msecs(waited), timeout, rc);
+
+	i2c_free_req(req);
+	if (rc)
+		return OPAL_HARDWARE;
+
+	return OPAL_SUCCESS;
+}