powerpc/powernv: Code update interface

Code update interface for powernv platform. This provides
sysfs interface to pass new image, validate, update and
commit images.

This patch includes:
  - Below OPAL APIs for code update
    - opal_validate_flash()
    - opal_manage_flash()
    - opal_update_flash()

  - Create below sysfs files under /sys/firmware/opal
    - image		: Interface to pass new FW image
    - validate_flash	: Validate candidate image
    - manage_flash	: Commit/Reject operations
    - update_flash	: Flash new candidate image

Updating Image:
  "update_flash" is an interface to indicate flash new FW.
It just passes image SG list to FW. Actual flashing is done
during system reboot time.

Note:
  - SG entry format:
    I have kept version number to keep this list similar to what
    PAPR is defined.
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/opal.h

@@ -129,6 +129,9 @@ extern int opal_enter_rtas(struct rtas_args *args,
 #define OPAL_LPC_READ				67
 #define OPAL_LPC_WRITE				68
 #define OPAL_RETURN_CPU				69
+#define OPAL_FLASH_VALIDATE			76
+#define OPAL_FLASH_MANAGE			77
+#define OPAL_FLASH_UPDATE			78
 
 #ifndef __ASSEMBLY__
 
@@ -724,6 +727,9 @@ int64_t opal_lpc_write(uint32_t chip_id, enum OpalLPCAddressType addr_type,
 		       uint32_t addr, uint32_t data, uint32_t sz);
 int64_t opal_lpc_read(uint32_t chip_id, enum OpalLPCAddressType addr_type,
 		      uint32_t addr, uint32_t *data, uint32_t sz);
+int64_t opal_validate_flash(uint64_t buffer, uint32_t *size, uint32_t *result);
+int64_t opal_manage_flash(uint8_t op);
+int64_t opal_update_flash(uint64_t blk_list);
 
 /* Internal functions */
 extern int early_init_dt_scan_opal(unsigned long node, const char *uname, int depth, void *data);
@@ -752,6 +758,7 @@ extern int opal_set_rtc_time(struct rtc_time *tm);
 extern void opal_get_rtc_time(struct rtc_time *tm);
 extern unsigned long opal_get_boot_time(void);
 extern void opal_nvram_init(void);
+extern void opal_flash_init(void);
 
 extern int opal_machine_check(struct pt_regs *regs);
 

arch/powerpc/platforms/powernv/Makefile

 obj-y			+= setup.o opal-takeover.o opal-wrappers.o opal.o
-obj-y			+= opal-rtc.o opal-nvram.o opal-lpc.o rng.o
+obj-y			+= opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
+obj-y			+= rng.o
 
 obj-$(CONFIG_SMP)	+= smp.o
 obj-$(CONFIG_PCI)	+= pci.o pci-p5ioc2.o pci-ioda.o

arch/powerpc/platforms/powernv/opal-wrappers.S

@@ -123,3 +123,6 @@ OPAL_CALL(opal_xscom_write,			OPAL_XSCOM_WRITE);
 OPAL_CALL(opal_lpc_read,			OPAL_LPC_READ);
 OPAL_CALL(opal_lpc_write,			OPAL_LPC_WRITE);
 OPAL_CALL(opal_return_cpu,			OPAL_RETURN_CPU);
+OPAL_CALL(opal_validate_flash,			OPAL_FLASH_VALIDATE);
+OPAL_CALL(opal_manage_flash,			OPAL_FLASH_MANAGE);
+OPAL_CALL(opal_update_flash,			OPAL_FLASH_UPDATE);

arch/powerpc/platforms/powernv/opal.c

@@ -438,6 +438,10 @@ static int __init opal_init(void)
 
 	/* Create "opal" kobject under /sys/firmware */
 	rc = opal_sysfs_init();
+	if (rc == 0) {
+		/* Setup code update interface */
+		opal_flash_init();
+	}
 
 	return 0;
 }