[M] Change in flashrom[master]: dummyflasher: use new API to register shutdown function

[Anastasia Klimchuk (Code Review)]

Anastasia Klimchuk has submitted this change. ( https://review.coreboot.org/c/flashrom/+/72408 )

Change subject: dummyflasher: use new API to register shutdown function
......................................................................

dummyflasher: use new API to register shutdown function

This allows masters to register shutdown function in *_master
struct, which means there is no need to call register_shutdown in init
function, since this call is now a part of register_*_master.

A dummy programmer can register masters for multiple buses that share a
programmer's data (a pointer to struct emu_data) with each other. To
avoid unexpected memory freeing by shutdown function, we need to keep
track of how many buses are using the shared resource. Use the
reference counting technique to achieve this.

TEST=ninja test

Change-Id: I0c67c25b0f53cd8c564c4ea0f09f2728e856f6ea
Signed-off-by: Alexander Goncharov 
Ticket: https://ticket.coreboot.org/issues/391
Reviewed-on: https://review.coreboot.org/c/flashrom/+/72408
Tested-by: build bot (Jenkins) 
Reviewed-by: Anastasia Klimchuk 
---
M dummyflasher.c
1 file changed, 52 insertions(+), 15 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Anastasia Klimchuk: Looks good to me, approved

diff --git a/dummyflasher.c b/dummyflasher.c
index 2bdd10c..0897332 100644
--- a/dummyflasher.c
+++ b/dummyflasher.c
@@ -75,6 +75,10 @@

unsigned int spi_write_256_chunksize;
    uint8_t *flashchip_contents;
+
+	/* An instance of this structure is shared between multiple masters, so
+	 * store the number of references to clean up only once at shutdown time. */
+	uint8_t refs_cnt;
 };

/* A legit complete SFDP table based on the MX25L6436E (rev. 1.8) datasheet. */
@@ -905,6 +909,11 @@
 {
    msg_pspew("%s\n", __func__);
    struct emu_data *emu_data = (struct emu_data *)data;
+
+	emu_data->refs_cnt--;
+	if (emu_data->refs_cnt != 0)
+		return 0;
+
    if (emu_data->emu_chip != EMULATE_NONE) {
    	if (emu_data->emu_persistent_image && emu_data->emu_modified) {
    		msg_pdbg("Writing %s\n", emu_data->emu_persistent_image);
@@ -933,6 +942,7 @@
    .multicommand	= default_spi_send_multicommand,
    .read		= default_spi_read,
    .write_256	= dummy_spi_write_256,
+	.shutdown	= dummy_shutdown,
    .probe_opcode	= dummy_spi_probe_opcode,
    .delay		= dummy_nop_delay,
 };
@@ -948,15 +958,17 @@
    .chip_writew	= dummy_chip_writew,
    .chip_writel	= dummy_chip_writel,
    .chip_writen	= dummy_chip_writen,
+	.shutdown	= dummy_shutdown,
    .delay		= dummy_nop_delay,
 };

static const struct opaque_master opaque_master_dummyflasher = {
-	.probe	= probe_variable_size,
-	.read	= dummy_opaque_read,
-	.write	= dummy_opaque_write,
-	.erase	= dummy_opaque_erase,
-	.delay	= dummy_nop_delay,
+	.probe		= probe_variable_size,
+	.read		= dummy_opaque_read,
+	.write		= dummy_opaque_write,
+	.erase		= dummy_opaque_erase,
+	.shutdown	= dummy_shutdown,
+	.delay		= dummy_nop_delay,
 };

static int init_data(const struct programmer_cfg *cfg,
@@ -1410,21 +1422,20 @@
    }

dummy_init_out:
-	if (register_shutdown(dummy_shutdown, data)) {
-		free(data->emu_persistent_image);
-		free(data->flashchip_contents);
-		free(data);
-		return 1;
-	}
-
-	if (dummy_buses_supported & BUS_PROG)
+	if (dummy_buses_supported & BUS_PROG) {
+		data->refs_cnt++;
    	ret |= register_opaque_master(&opaque_master_dummyflasher, data);
-	if (dummy_buses_supported & BUS_NONSPI)
+	}
+	if ((dummy_buses_supported & BUS_NONSPI) && !ret) {
+		data->refs_cnt++;
    	ret |= register_par_master(&par_master_dummyflasher,
    				   dummy_buses_supported & BUS_NONSPI,
    				   data);
-	if (dummy_buses_supported & BUS_SPI)
+	}
+	if ((dummy_buses_supported & BUS_SPI) && !ret) {
+		data->refs_cnt++;
    	ret |= register_spi_master(&spi_master_dummyflasher, data);
+	}

return ret;
 }