powerpc/pseries/lpar: add missing RTAS retry status handling

The ibm,get-system-parameter RTAS function may return -2 or 990x,
which indicate that the caller should try again.

pseries_lpar_read_hblkrm_characteristics() ignores this, making it
possible to incorrectly detect TLB block invalidation characteristics
at boot.

Move the RTAS call into a coventional rtas_busy_delay()-based loop.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Fixes: 1211ee61 ("powerpc/pseries: Read TLB Block Invalidate Characteristics")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230125-b4-powerpc-rtas-queue-v3-3-26929c8cce78@linux.ibm.com

arch/powerpc/platforms/pseries/lpar.c

@@ -1481,22 +1481,22 @@ static inline void __init check_lp_set_hblkrm(unsigned int lp,
 
 void __init pseries_lpar_read_hblkrm_characteristics(void)
 {
+	const s32 token = rtas_token("ibm,get-system-parameter");
 	unsigned char local_buffer[SPLPAR_TLB_BIC_MAXLENGTH];
 	int call_status, len, idx, bpsize;
 
 	if (!firmware_has_feature(FW_FEATURE_BLOCK_REMOVE))
 		return;
 
-	spin_lock(&rtas_data_buf_lock);
-	memset(rtas_data_buf, 0, RTAS_DATA_BUF_SIZE);
-	call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
-				NULL,
-				SPLPAR_TLB_BIC_TOKEN,
-				__pa(rtas_data_buf),
-				RTAS_DATA_BUF_SIZE);
-	memcpy(local_buffer, rtas_data_buf, SPLPAR_TLB_BIC_MAXLENGTH);
-	local_buffer[SPLPAR_TLB_BIC_MAXLENGTH - 1] = '\0';
-	spin_unlock(&rtas_data_buf_lock);
+	do {
+		spin_lock(&rtas_data_buf_lock);
+		memset(rtas_data_buf, 0, RTAS_DATA_BUF_SIZE);
+		call_status = rtas_call(token, 3, 1, NULL, SPLPAR_TLB_BIC_TOKEN,
+					__pa(rtas_data_buf), RTAS_DATA_BUF_SIZE);
+		memcpy(local_buffer, rtas_data_buf, SPLPAR_TLB_BIC_MAXLENGTH);
+		local_buffer[SPLPAR_TLB_BIC_MAXLENGTH - 1] = '\0';
+		spin_unlock(&rtas_data_buf_lock);
+	} while (rtas_busy_delay(call_status));
 
 	if (call_status != 0) {
 		pr_warn("%s %s Error calling get-system-parameter (0x%x)\n",