svn commit: r344733 - head/sys/dev/flash

[Ian Lepore]

Author: ian
Date: Sat Mar  2 22:28:43 2019
New Revision: 344733
URL: https://svnweb.freebsd.org/changeset/base/344733

Log:
  Add some comments.  Give #define'd names to some scattered numbers.  Change
  some #define'd names to be more descriptive.  When reporting a post-write
  compare failure, report the page number, not the byte address of the page.
  The latter is the only functional change, it makes the number match the
  words of the error message.

Modified:
  head/sys/dev/flash/at45d.c

Modified: head/sys/dev/flash/at45d.c
==============================================================================
--- head/sys/dev/flash/at45d.c	Sat Mar  2 21:30:01 2019	(r344732)
+++ head/sys/dev/flash/at45d.c	Sat Mar  2 22:28:43 2019	(r344733)
@@ -129,13 +129,17 @@ static int at45d_get_mfg_info(device_t dev, struct at4
 static int at45d_get_status(device_t dev, uint8_t *status);
 static int at45d_wait_ready(device_t dev, uint8_t *status);
 
-#define	BUFFER_TRANSFER			0x53
-#define	BUFFER_COMPARE			0x60
+#define	PAGE_TO_BUFFER_TRANSFER		0x53
+#define	PAGE_TO_BUFFER_COMPARE		0x60
 #define	PROGRAM_THROUGH_BUFFER		0x82
 #define	MANUFACTURER_ID			0x9f
 #define	STATUS_REGISTER_READ		0xd7
 #define	CONTINUOUS_ARRAY_READ		0xe8
 
+#define	STATUS_READY			(1u << 7)
+#define	STATUS_CMPFAIL			(1u << 6)
+#define	STATUS_PAGE2N			(1u << 0)
+
 /*
  * Metadata for supported chips.
  *
@@ -221,7 +225,7 @@ at45d_wait_ready(device_t dev, uint8_t *status)
 			err = ETIMEDOUT;
 		else
 			err = at45d_get_status(dev, status);
-	} while (err == 0 && (*status & 0x80) == 0);
+	} while (err == 0 && !(*status & STATUS_READY));
 	return (err);
 }
 
@@ -329,7 +333,7 @@ at45d_delayed_attach(void *xsc)
 
 	sc->pagecount = ident->pagecount;
 	sc->pageoffset = ident->pageoffset;
-	if (ident->pagesize2n != 0 && (status & 0x01) != 0) {
+	if (ident->pagesize2n != 0 && (status & STATUS_PAGE2N)) {
 		sc->pageoffset -= 1;
 		pagesize = ident->pagesize2n;
 	} else
@@ -378,6 +382,10 @@ at45d_getattr(struct bio *bp)
 {
 	struct at45d_softc *sc;
 
+	/*
+	 * This function exists to support geom_flashmap and fdt_slicer.
+	 */
+
 	if (bp->bio_disk == NULL || bp->bio_disk->d_drv1 == NULL)
 		return (ENXIO);
 	if (strcmp(bp->bio_attribute, "SPI::device") != 0)
@@ -434,7 +442,7 @@ at45d_task(void *arg)
 			}
 			bp = bioq_takefirst(&sc->bio_queue);
 			if (bp == NULL)
-				msleep(sc, &sc->sc_mtx, PRIBIO, "jobqueue", 0);
+				msleep(sc, &sc->sc_mtx, PRIBIO, "at45dq", 0);
 		} while (bp == NULL);
 		AT45D_UNLOCK(sc);
 
@@ -473,14 +481,19 @@ at45d_task(void *arg)
 			}
 			addr = page << sc->pageoffset;
 			if (bp->bio_cmd == BIO_WRITE) {
+				/*
+				 * If writing less than a full page, transfer
+				 * the existing page to the buffer, so that our
+				 * PROGRAM_THROUGH_BUFFER below will preserve
+				 * the parts of the page we're not writing.
+				 */
 				if (len != sc->pagesize) {
-					txBuf[0] = BUFFER_TRANSFER;
+					txBuf[0] = PAGE_TO_BUFFER_TRANSFER;
 					txBuf[1] = ((addr >> 16) & 0xff);
 					txBuf[2] = ((addr >> 8) & 0xff);
 					txBuf[3] = 0;
 					cmd.tx_data_sz = cmd.rx_data_sz = 0;
-					err = SPIBUS_TRANSFER(pdev, dev,
-					    &cmd);
+					err = SPIBUS_TRANSFER(pdev, dev, &cmd);
 					if (err == 0)
 						err = at45d_wait_ready(dev,
 						    &status);
@@ -506,7 +519,7 @@ at45d_task(void *arg)
 			}
 			if (bp->bio_cmd == BIO_WRITE) {
 				addr = page << sc->pageoffset;
-				txBuf[0] = BUFFER_COMPARE;
+				txBuf[0] = PAGE_TO_BUFFER_COMPARE;
 				txBuf[1] = ((addr >> 16) & 0xff);
 				txBuf[2] = ((addr >> 8) & 0xff);
 				txBuf[3] = 0;
@@ -514,9 +527,9 @@ at45d_task(void *arg)
 				err = SPIBUS_TRANSFER(pdev, dev, &cmd);
 				if (err == 0)
 					err = at45d_wait_ready(dev, &status);
-				if (err != 0 || (status & 0x40) != 0) {
+				if (err != 0 || (status & STATUS_CMPFAIL)) {
 					device_printf(dev, "comparing page "
-					    "%d failed (status=0x%x)\n", addr,
+					    "%d failed (status=0x%x)\n", page,
 					    status);
 					berr = EIO;
 					goto out;