[PATCH] net/e1000: implement protect and unprotect for attached flash

["Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>]

Some supported flash devices (e.g. SST25VF040) are write protected after
power up. If the device holds a valid firmware image the i210 can handle
that just fine. If however there is no firmware programmed, a procedure
is needed to remove this protection before an image can be flashed.

So implement the needed callbacks to make the commands protect and
unprotect do the right thing.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
Hello,

this is the last patch (for now at least) for my quest to improve flashing a
firmware image for i210. Up to today I was convinced I need to implement the
spi bitbanging access mode for the flash. But after I got this implemented up
to a working prototype I noticed that the already used flash burst mode can
also access the status register which results in less and prettier code.

Best regards
Uwe
 
 drivers/net/e1000/e1000.h  |  2 ++
 drivers/net/e1000/eeprom.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+)

diff --git a/drivers/net/e1000/e1000.h b/drivers/net/e1000/e1000.h
index b49e1198160a..50d49118f5e4 100644
--- a/drivers/net/e1000/e1000.h
+++ b/drivers/net/e1000/e1000.h
@@ -2110,6 +2110,8 @@ struct e1000_eeprom_info {
 #define E1000_FLSWCTL_CMD_WRITE		0b0001
 #define E1000_FLSWCTL_CMD_ERASE_SECTOR	0b0010
 #define E1000_FLSWCTL_CMD_ERASE_DEVICE	0b0011
+#define E1000_FLSWCTL_CMD_RDSR		0b0100
+#define E1000_FLSWCTL_CMD_WRSR		0b0101
 #define E1000_FLSWCTL_CMD(c)		((0b1111 & (c)) << 24)
 
 #define E1000_FLSWCTL_CMD_ADDR_MASK	0x0FFFFFFF
diff --git a/drivers/net/e1000/eeprom.c b/drivers/net/e1000/eeprom.c
index 0f1305c8499b..eeae318dcdfa 100644
--- a/drivers/net/e1000/eeprom.c
+++ b/drivers/net/e1000/eeprom.c
@@ -3,6 +3,7 @@
 #include <malloc.h>
 #include <linux/math64.h>
 #include <linux/sizes.h>
+#include <linux/mtd/spi-nor.h>
 
 #include "e1000.h"
 
@@ -1410,6 +1411,73 @@ fail:
 	return ret;
 }
 
+static int e1000_mtd_sr_rmw(struct mtd_info *mtd, u8 mask, u8 val)
+{
+	struct e1000_hw *hw = container_of(mtd, struct e1000_hw, mtd);
+	uint32_t flswdata;
+	int ret;
+
+	ret = e1000_flash_mode_wait_for_idle(hw);
+	if (ret < 0)
+		return ret;
+
+	e1000_write_reg(hw, E1000_FLSWCNT, 1);
+	e1000_flash_cmd(hw, E1000_FLSWCTL_CMD_RDSR, 0);
+
+	ret = e1000_flash_mode_check_command_valid(hw);
+	if (ret < 0)
+		return -EIO;
+
+	ret = e1000_poll_reg(hw, E1000_FLSWCTL,
+			     E1000_FLSWCTL_DONE, E1000_FLSWCTL_DONE,
+			     SECOND);
+	if (ret < 0) {
+		dev_err(hw->dev,
+			"Timeout waiting for FLSWCTL.DONE to be set (RDSR)\n");
+		return ret;
+	}
+
+	flswdata = e1000_read_reg(hw, E1000_FLSWDATA);
+
+	flswdata = (flswdata & ~mask) | val;
+
+	e1000_write_reg(hw, E1000_FLSWCNT, 1);
+	e1000_flash_cmd(hw, E1000_FLSWCTL_CMD_WRSR, 0);
+
+	ret = e1000_flash_mode_check_command_valid(hw);
+	if (ret < 0)
+		return -EIO;
+
+	e1000_write_reg(hw, E1000_FLSWDATA, flswdata);
+
+	ret = e1000_poll_reg(hw, E1000_FLSWCTL,
+			     E1000_FLSWCTL_DONE, E1000_FLSWCTL_DONE,
+			     SECOND);
+	if (ret < 0) {
+		dev_err(hw->dev,
+			"Timeout waiting for FLSWCTL.DONE to be set (WRSR)\n");
+	}
+
+	return ret;
+}
+
+/*
+ * The available spi nor devices are very different in how the block protection
+ * bits affect which sectors to be protected. So take the simple approach and
+ * only use BP[012] = b000 (unprotected) and BP[012] = b111 (protected).
+ */
+#define SR_BPALL (SR_BP0 | SR_BP1 | SR_BP2)
+
+static int e1000_mtd_lock(struct mtd_info *mtd, loff_t ofs, size_t len)
+{
+	return e1000_mtd_sr_rmw(mtd, SR_BPALL, SR_BPALL);
+}
+
+static int e1000_mtd_unlock(struct mtd_info *mtd, loff_t ofs, size_t len)
+{
+	return e1000_mtd_sr_rmw(mtd, SR_BPALL, 0x0);
+}
+
 int e1000_register_invm(struct e1000_hw *hw)
 {
 	int ret;
@@ -1521,6 +1589,8 @@ int e1000_register_eeprom(struct e1000_hw *hw)
 			hw->mtd.read = e1000_mtd_read;
 			hw->mtd.write = e1000_mtd_write;
 			hw->mtd.erase = e1000_mtd_erase;
+			hw->mtd.lock = e1000_mtd_lock;
+			hw->mtd.unlock = e1000_mtd_unlock;
 			hw->mtd.size = eeprom->word_size * 2;
 			hw->mtd.writesize = 1;
 			hw->mtd.subpage_sft = 0;
-- 
2.11.0


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