wl18xx: FDSP Code RAM Corruption fix

In PG2.0 there is an issue where PHY's FDSP Code RAM sometimes gets
corrupted when exiting from ELP mode. This issue is related to FDSP
Code RAM clock implementation.

PG2.1 introduces a HW fix for this issue that requires the driver to
change the FDSP Code Ram clock settings (mux it to ATGP clock instead
of its own clock).

This workaround uses PHY_FPGA_SPARE_1 register and is relevant to WL8
PG2.1 devices.

The fix is also backward compatible with older PG2.0 devices where the
register PHY_FPGA_SPARE_1 is not used and not connected.

The fix is done in the wl18xx_pre_upload function (must be performed
before uploading the FW code) and includes the following steps:

1. Disable FDSP clock
2. Set ATPG clock toward FDSP Code RAM rather than its own clock.
3. Re-enable FDSP clock
Signed-off-by: Yair Shapira <yair.shapira@ti.com>
Signed-off-by: Ido Reis <idor@ti.com>
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

drivers/net/wireless/ti/wl18xx/main.c

@@ -594,8 +594,8 @@ static const struct wlcore_partition_set wl18xx_ptable[PART_TABLE_LEN] = {
 		.mem3 = { .start = 0x00000000, .size  = 0x00000000 },
 	},
 	[PART_PHY_INIT] = {
-		.mem  = { .start = 0x80926000,
-			  .size = sizeof(struct wl18xx_mac_and_phy_params) },
+		.mem  = { .start = WL18XX_PHY_INIT_MEM_ADDR,
+			  .size  = WL18XX_PHY_INIT_MEM_SIZE },
 		.reg  = { .start = 0x00000000, .size = 0x00000000 },
 		.mem2 = { .start = 0x00000000, .size = 0x00000000 },
 		.mem3 = { .start = 0x00000000, .size = 0x00000000 },
@@ -799,6 +799,9 @@ static int wl18xx_pre_upload(struct wl1271 *wl)
 	u32 tmp;
 	int ret;
 
+	BUILD_BUG_ON(sizeof(struct wl18xx_mac_and_phy_params) >
+		WL18XX_PHY_INIT_MEM_SIZE);
+
 	ret = wlcore_set_partition(wl, &wl->ptable[PART_BOOT]);
 	if (ret < 0)
 		goto out;
@@ -815,6 +818,35 @@ static int wl18xx_pre_upload(struct wl1271 *wl)
 	wl1271_debug(DEBUG_BOOT, "chip id 0x%x", tmp);
 
 	ret = wlcore_read32(wl, WL18XX_SCR_PAD2, &tmp);
+	if (ret < 0)
+		goto out;
+
+	/*
+	 * Workaround for FDSP code RAM corruption (needed for PG2.1
+	 * and newer; for older chips it's a NOP).  Change FDSP clock
+	 * settings so that it's muxed to the ATGP clock instead of
+	 * its own clock.
+	 */
+
+	ret = wlcore_set_partition(wl, &wl->ptable[PART_PHY_INIT]);
+	if (ret < 0)
+		goto out;
+
+	/* disable FDSP clock */
+	ret = wlcore_write32(wl, WL18XX_PHY_FPGA_SPARE_1,
+			     MEM_FDSP_CLK_120_DISABLE);
+	if (ret < 0)
+		goto out;
+
+	/* set ATPG clock toward FDSP Code RAM rather than its own clock */
+	ret = wlcore_write32(wl, WL18XX_PHY_FPGA_SPARE_1,
+			     MEM_FDSP_CODERAM_FUNC_CLK_SEL);
+	if (ret < 0)
+		goto out;
+
+	/* re-enable FDSP clock */
+	ret = wlcore_write32(wl, WL18XX_PHY_FPGA_SPARE_1,
+			     MEM_FDSP_CLK_120_ENABLE);
 
 out:
 	return ret;

drivers/net/wireless/ti/wl18xx/reg.h

@@ -38,6 +38,9 @@
 #define WL18XX_REG_BOOT_PART_SIZE  0x00014578
 
 #define WL18XX_PHY_INIT_MEM_ADDR   0x80926000
+#define WL18XX_PHY_END_MEM_ADDR	   0x8093CA44
+#define WL18XX_PHY_INIT_MEM_SIZE \
+	(WL18XX_PHY_END_MEM_ADDR - WL18XX_PHY_INIT_MEM_ADDR)
 
 #define WL18XX_SDIO_WSPI_BASE		(WL18XX_REGISTERS_BASE)
 #define WL18XX_REG_CONFIG_BASE		(WL18XX_REGISTERS_BASE + 0x02000)
@@ -217,4 +220,16 @@ static const char * const rdl_names[] = {
 	[RDL_4_SP]	= "1897 MIMO",
 };
 
+/* FPGA_SPARE_1 register - used to change the PHY ATPG clock at boot time */
+#define WL18XX_PHY_FPGA_SPARE_1		0x8093CA40
+
+/* command to disable FDSP clock */
+#define MEM_FDSP_CLK_120_DISABLE        0x80000000
+
+/* command to set ATPG clock toward FDSP Code RAM rather than its own clock */
+#define MEM_FDSP_CODERAM_FUNC_CLK_SEL	0xC0000000
+
+/* command to re-enable FDSP clock */
+#define MEM_FDSP_CLK_120_ENABLE		0x40000000
+
 #endif /* __REG_H__ */