linux/ena: Extend support to 256 reset reasons

Currently we only use 4 bits in order to define the reset reason.
This allows us to define 16 reset reasons which have already been used
up. In order to allow for more reset reasons to be defined and detected,
this patch will extend the reset reason up to 8 bits which allows
256 reset reasons.

For backward compatibility reasons, bits 28-31 will represent the LSB
and bits 24-27 will represent the MSB in the relevant register.
This way when an old driver writes a reset reason it will be compatible
with the newer devices.

Also, in case the device does not support extended reset reasons, the
driver will identify it and fall back to GENERIC reset reason.
When using an old driver all reset reasons are mapped correctly
except of ENA_REGS_RESET_RX_DESCRIPTOR_MALFORMED since it was
already defined with index 16 before extending the reset
reasons support, in this case the device will interpret the
reset reason as ENA_REGS_RESET_NORMAL.

Signed-off-by: Osama Abboud <[email protected]>

kernel/linux/common/ena_com/ena_admin_defs.h

@@ -83,6 +83,7 @@ enum ena_admin_aq_caps_id {
 	/* ENA SRD customer metrics */
 	ENA_ADMIN_ENA_SRD_INFO                      = 1,
 	ENA_ADMIN_CUSTOMER_METRICS                  = 2,
+	ENA_ADMIN_EXTENDED_RESET_REASONS	    = 3,
 };
 
 enum ena_admin_placement_policy_type {

kernel/linux/common/ena_com/ena_com.c

@@ -2407,6 +2407,7 @@ void ena_com_aenq_intr_handler(struct ena_com_dev *ena_dev, void *data)
 int ena_com_dev_reset(struct ena_com_dev *ena_dev,
 		      enum ena_regs_reset_reason_types reset_reason)
 {
+	u32 reset_reason_msb, reset_reason_lsb;
 	u32 stat, timeout, cap, reset_val;
 	int rc;
 
@@ -2434,8 +2435,28 @@ int ena_com_dev_reset(struct ena_com_dev *ena_dev,
 
 	/* start reset */
 	reset_val = ENA_REGS_DEV_CTL_DEV_RESET_MASK;
-	reset_val |= (reset_reason << ENA_REGS_DEV_CTL_RESET_REASON_SHIFT) &
-		     ENA_REGS_DEV_CTL_RESET_REASON_MASK;
+
+	/* For backward compatibility, device will interpret
+	 * bits 24-27 as MSB, bits 28-31 as LSB
+	 */
+	reset_reason_lsb = ENA_FIELD_GET(reset_reason, ENA_RESET_REASON_LSB_MASK,
+					 ENA_RESET_REASON_LSB_OFFSET);
+
+	reset_reason_msb = ENA_FIELD_GET(reset_reason, ENA_RESET_REASON_MSB_MASK,
+					 ENA_RESET_REASON_MSB_OFFSET);
+
+	reset_val |= reset_reason_lsb << ENA_REGS_DEV_CTL_RESET_REASON_SHIFT;
+
+	if (ena_com_get_cap(ena_dev, ENA_ADMIN_EXTENDED_RESET_REASONS))
+		reset_val |= reset_reason_msb << ENA_REGS_DEV_CTL_RESET_REASON_EXT_SHIFT;
+	else if (reset_reason_msb) {
+		/* In case the device does not support intended
+		 * extended reset reason fallback to generic
+		 */
+		reset_val = ENA_REGS_DEV_CTL_DEV_RESET_MASK;
+		reset_val |= (ENA_REGS_RESET_GENERIC << ENA_REGS_DEV_CTL_RESET_REASON_SHIFT) &
+			      ENA_REGS_DEV_CTL_RESET_REASON_MASK;
+	}
 	writel(reset_val, ena_dev->reg_bar + ENA_REGS_DEV_CTL_OFF);
 
 	/* Write again the MMIO read request address */

kernel/linux/common/ena_com/ena_com.h

@@ -42,6 +42,14 @@
 #define ADMIN_CQ_SIZE(depth)	((depth) * sizeof(struct ena_admin_acq_entry))
 #define ADMIN_AENQ_SIZE(depth)	((depth) * sizeof(struct ena_admin_aenq_entry))
 
+/* Macros used to extract LSB/MSB from the
+ * enums defining the reset reasons
+ */
+#define ENA_RESET_REASON_LSB_OFFSET			    0
+#define ENA_RESET_REASON_LSB_MASK			    0xf
+#define ENA_RESET_REASON_MSB_OFFSET			    4
+#define ENA_RESET_REASON_MSB_MASK			    0xf0
+
 #define ENA_CUSTOMER_METRICS_BUFFER_SIZE 512
 
 /*****************************************************************************/

kernel/linux/common/ena_com/ena_regs_defs.h

@@ -105,6 +105,8 @@ enum ena_regs_reset_reason_types {
 #define ENA_REGS_DEV_CTL_QUIESCENT_MASK                     0x4
 #define ENA_REGS_DEV_CTL_IO_RESUME_SHIFT                    3
 #define ENA_REGS_DEV_CTL_IO_RESUME_MASK                     0x8
+#define ENA_REGS_DEV_CTL_RESET_REASON_EXT_SHIFT             24
+#define ENA_REGS_DEV_CTL_RESET_REASON_EXT_MASK              0xf000000
 #define ENA_REGS_DEV_CTL_RESET_REASON_SHIFT                 28
 #define ENA_REGS_DEV_CTL_RESET_REASON_MASK                  0xf0000000
 

kernel/linux/ena/kcompat.h

@@ -1122,6 +1122,13 @@ static inline void ena_netif_napi_add(struct net_device *dev,
 #define ENA_LARGE_LLQ_ETHTOOL
 #endif
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)
+#include <linux/bitfield.h>
+#define ENA_FIELD_GET(value, mask, offset) FIELD_GET(mask, value)
+#else
+#define ENA_FIELD_GET(value, mask, offset) ((typeof(mask))((value & mask) >> offset))
+#endif
+
 #if defined(ENA_DEVLINK_SUPPORT) && LINUX_VERSION_CODE < KERNEL_VERSION(6, 3, 0)
 #define devl_param_driverinit_value_get devlink_param_driverinit_value_get
 #define devl_param_driverinit_value_set devlink_param_driverinit_value_set