Thread (16 messages) flat view 16 messages, 5 authors, 2016-02-26
STALE3819d

[PATCH v3] ARM64: kernel: implement ACPI parking protocol

From: Lorenzo Pieralisi <hidden>
Date: 2016-02-24 15:03:14
Also in: linux-acpi

On Wed, Feb 24, 2016 at 02:18:32PM +0000, Lorenzo Pieralisi wrote:

[...]
quoted hunk ↗ jump to hunk
 static int acpi_parking_protocol_cpu_boot(unsigned int cpu)
 {
 	struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu];
@@ -107,7 +108,11 @@ static int acpi_parking_protocol_cpu_boot(unsigned int cpu)
 
 	arch_send_wakeup_ipi_mask(cpumask_of(cpu));
 
-	iounmap(mailbox);
+	/*
+	 * stash the mailbox address mapping to use it for checks
+	 * in post boot method
+	 */
+	cpu_entry->mailbox = mailbox;
The mailbox VA entry should be stashed before setting up the mailbox
and sending the IPI, anyway, if Loc and Itaru can test it I will wrap
this change into the final version with appropriate log.

Lorenzo
quoted hunk ↗ jump to hunk
 
 	return 0;
 }
@@ -116,32 +121,15 @@ static void acpi_parking_protocol_cpu_postboot(void)
 {
 	int cpu = smp_processor_id();
 	struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu];
-	struct parking_protocol_mailbox __iomem *mailbox;
+	struct parking_protocol_mailbox __iomem *mailbox = cpu_entry->mailbox;
 	__le64 entry_point;
 
-	/*
-	 * Map mailbox memory with attribute device nGnRE (ie ioremap -
-	 * this deviates from the parking protocol specifications since
-	 * the mailboxes are required to be mapped nGnRnE; the attribute
-	 * discrepancy is harmless insofar as the protocol specification
-	 * is concerned).
-	 * If the mailbox is mistakenly allocated in the linear mapping
-	 * by FW ioremap will fail since the mapping will be prevented
-	 * by the kernel (it clashes with the linear mapping attributes
-	 * specifications).
-	 */
-	mailbox = ioremap(cpu_entry->mailbox_addr, sizeof(*mailbox));
-	if (!mailbox)
-		return;
-
 	entry_point = readl_relaxed(&mailbox->entry_point);
 	/*
 	 * Check if firmware has cleared the entry_point as expected
 	 * by the protocol specification.
 	 */
 	WARN_ON(entry_point);
-
-	iounmap(mailbox);
 }
 
 const struct cpu_operations acpi_parking_protocol_ops = {
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