[PATCH v1 1/4] net: ti: netcp: restore get/set_pad_info() functionality

[PATCH v1 1/4] net: ti: netcp: restore get/set_pad_info() functionality

[Murali Karicheri]

From: Arnd Bergmann <arnd@arndb.de>

The commit 899077791403 ("netcp: try to reduce type confusion in
descriptors") introduces a regression in Kernel 4.5-rc1 and it breaks
get/set_pad_info() functionality.

The TI NETCP driver uses pad0 and pad1 fields of knav_dma_desc to
store DMA/MEM buffer pointer and buffer size respectively. And in both
cases for Keystone 2 the pointer type size is 32 bit regardless of
LAPE enabled or not, because CONFIG_ARCH_DMA_ADDR_T_64BIT originally
is not expected to be defined.

			!LAPE	LPAE
sizeof(void*)		32bit	32bit
sizeof(dma_addr_t) 	32bit	32bit
sizeof(phys_addr_t) 	32bit	64bit

Unfortunately, above commit changed buffer's pointers save/restore
code (get/set_pad_info()) and added intermediate conversation to u64
which works incorrectly on 32bit Keystone 2 and causes TI NETCP driver
crash in RX/TX path due to "Unable to handle kernel NULL pointer"
exception. This issue was reported and discussed in [1].

Hence, fix it by partially reverting above commit and restoring
get/set_pad_info() functionality as it was before.

[1] https://www.mail-archive.com/netdev@vger.kernel.org/msg95361.html
Cc: Wingman Kwok <w-kwok2@ti.com>
Cc: Mugunthan V N <mugunthanvnm@ti.com>
CC: David Laight <David.Laight@ACULAB.COM>
Reported-by: Franklin S Cooper Jr <fcooper@ti.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
---
 v1 - Just fixed a checkpatch warning for commit description
 drivers/net/ethernet/ti/netcp_core.c | 59 +++++++++++-------------------------
 1 file changed, 18 insertions(+), 41 deletions(-)

diff --git a/drivers/net/ethernet/ti/netcp_core.c b/drivers/net/ethernet/ti/netcp_core.c
index c61d66d..0b26e52 100644
--- a/drivers/net/ethernet/ti/netcp_core.c
+++ b/drivers/net/ethernet/ti/netcp_core.c
@@ -117,20 +117,10 @@ static void get_pkt_info(dma_addr_t *buff, u32 *buff_len, dma_addr_t *ndesc,
 	*ndesc = le32_to_cpu(desc->next_desc);
 }
 
-static void get_pad_info(u32 *pad0, u32 *pad1, u32 *pad2, struct knav_dma_desc *desc)
+static void get_pad_info(u32 *pad0, u32 *pad1, struct knav_dma_desc *desc)
 {
 	*pad0 = le32_to_cpu(desc->pad[0]);
 	*pad1 = le32_to_cpu(desc->pad[1]);
-	*pad2 = le32_to_cpu(desc->pad[2]);
-}
-
-static void get_pad_ptr(void **padptr, struct knav_dma_desc *desc)
-{
-	u64 pad64;
-
-	pad64 = le32_to_cpu(desc->pad[0]) +
-		((u64)le32_to_cpu(desc->pad[1]) << 32);
-	*padptr = (void *)(uintptr_t)pad64;
 }
 
 static void get_org_pkt_info(dma_addr_t *buff, u32 *buff_len,
@@ -163,11 +153,10 @@ static void set_desc_info(u32 desc_info, u32 pkt_info,
 	desc->packet_info = cpu_to_le32(pkt_info);
 }
 
-static void set_pad_info(u32 pad0, u32 pad1, u32 pad2, struct knav_dma_desc *desc)
+static void set_pad_info(u32 pad0, u32 pad1, struct knav_dma_desc *desc)
 {
 	desc->pad[0] = cpu_to_le32(pad0);
 	desc->pad[1] = cpu_to_le32(pad1);
-	desc->pad[2] = cpu_to_le32(pad1);
 }
 
 static void set_org_pkt_info(dma_addr_t buff, u32 buff_len,
@@ -581,7 +570,6 @@ static void netcp_free_rx_desc_chain(struct netcp_intf *netcp,
 	dma_addr_t dma_desc, dma_buf;
 	unsigned int buf_len, dma_sz = sizeof(*ndesc);
 	void *buf_ptr;
-	u32 pad[2];
 	u32 tmp;
 
 	get_words(&dma_desc, 1, &desc->next_desc);
@@ -593,14 +581,12 @@ static void netcp_free_rx_desc_chain(struct netcp_intf *netcp,
 			break;
 		}
 		get_pkt_info(&dma_buf, &tmp, &dma_desc, ndesc);
-		get_pad_ptr(&buf_ptr, ndesc);
+		get_pad_info((u32 *)&buf_ptr, &buf_len, ndesc);
 		dma_unmap_page(netcp->dev, dma_buf, PAGE_SIZE, DMA_FROM_DEVICE);
 		__free_page(buf_ptr);
 		knav_pool_desc_put(netcp->rx_pool, desc);
 	}
-
-	get_pad_info(&pad[0], &pad[1], &buf_len, desc);
-	buf_ptr = (void *)(uintptr_t)(pad[0] + ((u64)pad[1] << 32));
+	get_pad_info((u32 *)&buf_ptr, &buf_len, desc);
 
 	if (buf_ptr)
 		netcp_frag_free(buf_len <= PAGE_SIZE, buf_ptr);
@@ -639,8 +625,8 @@ static int netcp_process_one_rx_packet(struct netcp_intf *netcp)
 	dma_addr_t dma_desc, dma_buff;
 	struct netcp_packet p_info;
 	struct sk_buff *skb;
-	u32 pad[2];
 	void *org_buf_ptr;
+	u32 tmp;
 
 	dma_desc = knav_queue_pop(netcp->rx_queue, &dma_sz);
 	if (!dma_desc)
@@ -653,8 +639,7 @@ static int netcp_process_one_rx_packet(struct netcp_intf *netcp)
 	}
 
 	get_pkt_info(&dma_buff, &buf_len, &dma_desc, desc);
-	get_pad_info(&pad[0], &pad[1], &org_buf_len, desc);
-	org_buf_ptr = (void *)(uintptr_t)(pad[0] + ((u64)pad[1] << 32));
+	get_pad_info((u32 *)&org_buf_ptr, &org_buf_len, desc);
 
 	if (unlikely(!org_buf_ptr)) {
 		dev_err(netcp->ndev_dev, "NULL bufptr in desc\n");
@@ -679,7 +664,6 @@ static int netcp_process_one_rx_packet(struct netcp_intf *netcp)
 	/* Fill in the page fragment list */
 	while (dma_desc) {
 		struct page *page;
-		void *ptr;
 
 		ndesc = knav_pool_desc_unmap(netcp->rx_pool, dma_desc, dma_sz);
 		if (unlikely(!ndesc)) {
@@ -688,8 +672,7 @@ static int netcp_process_one_rx_packet(struct netcp_intf *netcp)
 		}
 
 		get_pkt_info(&dma_buff, &buf_len, &dma_desc, ndesc);
-		get_pad_ptr(&ptr, ndesc);
-		page = ptr;
+		get_pad_info((u32 *)&page, &tmp, ndesc);
 
 		if (likely(dma_buff && buf_len && page)) {
 			dma_unmap_page(netcp->dev, dma_buff, PAGE_SIZE,
@@ -767,6 +750,7 @@ static void netcp_free_rx_buf(struct netcp_intf *netcp, int fdq)
 	unsigned int buf_len, dma_sz;
 	dma_addr_t dma;
 	void *buf_ptr;
+	u32 tmp;
 
 	/* Allocate descriptor */
 	while ((dma = knav_queue_pop(netcp->rx_fdq[fdq], &dma_sz))) {
@@ -777,7 +761,7 @@ static void netcp_free_rx_buf(struct netcp_intf *netcp, int fdq)
 		}
 
 		get_org_pkt_info(&dma, &buf_len, desc);
-		get_pad_ptr(&buf_ptr, desc);
+		get_pad_info((u32 *)&buf_ptr, &tmp, desc);
 
 		if (unlikely(!dma)) {
 			dev_err(netcp->ndev_dev, "NULL orig_buff in desc\n");
@@ -829,7 +813,7 @@ static int netcp_allocate_rx_buf(struct netcp_intf *netcp, int fdq)
 	struct page *page;
 	dma_addr_t dma;
 	void *bufptr;
-	u32 pad[3];
+	u32 pad[2];
 
 	/* Allocate descriptor */
 	hwdesc = knav_pool_desc_get(netcp->rx_pool);
@@ -846,7 +830,7 @@ static int netcp_allocate_rx_buf(struct netcp_intf *netcp, int fdq)
 				SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 
 		bufptr = netdev_alloc_frag(primary_buf_len);
-		pad[2] = primary_buf_len;
+		pad[1] = primary_buf_len;
 
 		if (unlikely(!bufptr)) {
 			dev_warn_ratelimited(netcp->ndev_dev,
@@ -858,9 +842,7 @@ static int netcp_allocate_rx_buf(struct netcp_intf *netcp, int fdq)
 		if (unlikely(dma_mapping_error(netcp->dev, dma)))
 			goto fail;
 
-		pad[0] = lower_32_bits((uintptr_t)bufptr);
-		pad[1] = upper_32_bits((uintptr_t)bufptr);
-
+		pad[0] = (u32)bufptr;
 	} else {
 		/* Allocate a secondary receive queue entry */
 		page = alloc_page(GFP_ATOMIC | GFP_DMA | __GFP_COLD);
@@ -870,9 +852,8 @@ static int netcp_allocate_rx_buf(struct netcp_intf *netcp, int fdq)
 		}
 		buf_len = PAGE_SIZE;
 		dma = dma_map_page(netcp->dev, page, 0, buf_len, DMA_TO_DEVICE);
-		pad[0] = lower_32_bits(dma);
-		pad[1] = upper_32_bits(dma);
-		pad[2] = 0;
+		pad[0] = (u32)page;
+		pad[1] = 0;
 	}
 
 	desc_info =  KNAV_DMA_DESC_PS_INFO_IN_DESC;
@@ -882,7 +863,7 @@ static int netcp_allocate_rx_buf(struct netcp_intf *netcp, int fdq)
 	pkt_info |= (netcp->rx_queue_id & KNAV_DMA_DESC_RETQ_MASK) <<
 		    KNAV_DMA_DESC_RETQ_SHIFT;
 	set_org_pkt_info(dma, buf_len, hwdesc);
-	set_pad_info(pad[0], pad[1], pad[2], hwdesc);
+	set_pad_info(pad[0], pad[1], hwdesc);
 	set_desc_info(desc_info, pkt_info, hwdesc);
 
 	/* Push to FDQs */
@@ -971,11 +952,11 @@ static int netcp_process_tx_compl_packets(struct netcp_intf *netcp,
 					  unsigned int budget)
 {
 	struct knav_dma_desc *desc;
-	void *ptr;
 	struct sk_buff *skb;
 	unsigned int dma_sz;
 	dma_addr_t dma;
 	int pkts = 0;
+	u32 tmp;
 
 	while (budget--) {
 		dma = knav_queue_pop(netcp->tx_compl_q, &dma_sz);
@@ -988,8 +969,7 @@ static int netcp_process_tx_compl_packets(struct netcp_intf *netcp,
 			continue;
 		}
 
-		get_pad_ptr(&ptr, desc);
-		skb = ptr;
+		get_pad_info((u32 *)&skb, &tmp, desc);
 		netcp_free_tx_desc_chain(netcp, desc, dma_sz);
 		if (!skb) {
 			dev_err(netcp->ndev_dev, "No skb in Tx desc\n");
@@ -1194,10 +1174,7 @@ static int netcp_tx_submit_skb(struct netcp_intf *netcp,
 	}
 
 	set_words(&tmp, 1, &desc->packet_info);
-	tmp = lower_32_bits((uintptr_t)&skb);
-	set_words(&tmp, 1, &desc->pad[0]);
-	tmp = upper_32_bits((uintptr_t)&skb);
-	set_words(&tmp, 1, &desc->pad[1]);
+	set_words((u32 *)&skb, 1, &desc->pad[0]);
 
 	if (tx_pipe->flags & SWITCH_TO_PORT_IN_TAGINFO) {
 		tmp = tx_pipe->switch_to_port;
-- 
1.9.1

[PATCH v1 2/4] soc: ti: knav_dma: rename pad in struct knav_dma_desc to sw_data

[Murali Karicheri]

Rename the pad to sw_data as per description of this field in the hardware
spec(refer sprugr9 from www.ti.com). Latest version of the document is
at http://www.ti.com/lit/ug/sprugr9h/sprugr9h.pdf and section 3.1
Host Packet Descriptor describes this field.

Also define and use a constant for the size of sw_data field similar to
other fields in the struct for desc and document the sw_data field
in the header. As the sw_data is not touched by hw, it's type can be
changed to u32.

Cc: Wingman Kwok <w-kwok2@ti.com>
Cc: Mugunthan V N <mugunthanvnm@ti.com>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Grygorii Strashko <grygorii.strashko@ti.com>
CC: David Laight <David.Laight@ACULAB.COM>
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
---
 new patch based on discussion at https://patchwork.ozlabs.org/patch/580860/
 include/linux/soc/ti/knav_dma.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/linux/soc/ti/knav_dma.h b/include/linux/soc/ti/knav_dma.h
index 343c13a..35cb926 100644
--- a/include/linux/soc/ti/knav_dma.h
+++ b/include/linux/soc/ti/knav_dma.h
@@ -44,6 +44,7 @@
 
 #define KNAV_DMA_NUM_EPIB_WORDS			4
 #define KNAV_DMA_NUM_PS_WORDS			16
+#define KNAV_DMA_NUM_SW_DATA_WORDS		4
 #define KNAV_DMA_FDQ_PER_CHAN			4
 
 /* Tx channel scheduling priority */
@@ -142,6 +143,7 @@ struct knav_dma_cfg {
  * @orig_buff:			buff pointer since 'buff' can be overwritten
  * @epib:			Extended packet info block
  * @psdata:			Protocol specific
+ * @sw_data:			Software private data not touched by h/w
  */
 struct knav_dma_desc {
 	__le32	desc_info;
@@ -154,7 +156,7 @@ struct knav_dma_desc {
 	__le32	orig_buff;
 	__le32	epib[KNAV_DMA_NUM_EPIB_WORDS];
 	__le32	psdata[KNAV_DMA_NUM_PS_WORDS];
-	__le32	pad[4];
+	u32	sw_data[KNAV_DMA_NUM_SW_DATA_WORDS];
 } ____cacheline_aligned;
 
 #if IS_ENABLED(CONFIG_KEYSTONE_NAVIGATOR_DMA)
-- 
1.9.1

[PATCH v1 3/4] net: netcp: rename {get/set}pad_info to {get/set}_sw_data

[Murali Karicheri]

Rename the helpers to match with the updated dma desc field sw_data.

Cc: Wingman Kwok <w-kwok2@ti.com>
Cc: Mugunthan V N <mugunthanvnm@ti.com>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Grygorii Strashko <grygorii.strashko@ti.com>
CC: David Laight <David.Laight@ACULAB.COM>
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
---
 v1 - new patch to based on discussion at
	https://patchwork.ozlabs.org/patch/580860/
 drivers/net/ethernet/ti/netcp_core.c | 40 +++++++++++++++++++-----------------
 1 file changed, 21 insertions(+), 19 deletions(-)

diff --git a/drivers/net/ethernet/ti/netcp_core.c b/drivers/net/ethernet/ti/netcp_core.c
index 0b26e52..1d07cca 100644
--- a/drivers/net/ethernet/ti/netcp_core.c
+++ b/drivers/net/ethernet/ti/netcp_core.c
@@ -117,10 +117,11 @@ static void get_pkt_info(dma_addr_t *buff, u32 *buff_len, dma_addr_t *ndesc,
 	*ndesc = le32_to_cpu(desc->next_desc);
 }
 
-static void get_pad_info(u32 *pad0, u32 *pad1, struct knav_dma_desc *desc)
+static void get_sw_data(u32 *data0, u32 *data1, struct knav_dma_desc *desc)
 {
-	*pad0 = le32_to_cpu(desc->pad[0]);
-	*pad1 = le32_to_cpu(desc->pad[1]);
+	/* No Endian conversion needed as this data is untouched by hw */
+	*data0 = desc->sw_data[0];
+	*data1 = desc->sw_data[1];
 }
 
 static void get_org_pkt_info(dma_addr_t *buff, u32 *buff_len,
@@ -153,10 +154,11 @@ static void set_desc_info(u32 desc_info, u32 pkt_info,
 	desc->packet_info = cpu_to_le32(pkt_info);
 }
 
-static void set_pad_info(u32 pad0, u32 pad1, struct knav_dma_desc *desc)
+static void set_sw_data(u32 data0, u32 data1, struct knav_dma_desc *desc)
 {
-	desc->pad[0] = cpu_to_le32(pad0);
-	desc->pad[1] = cpu_to_le32(pad1);
+	/* No Endian conversion needed as this data is untouched by hw */
+	desc->sw_data[0] = data0;
+	desc->sw_data[1] = data1;
 }
 
 static void set_org_pkt_info(dma_addr_t buff, u32 buff_len,
@@ -581,12 +583,12 @@ static void netcp_free_rx_desc_chain(struct netcp_intf *netcp,
 			break;
 		}
 		get_pkt_info(&dma_buf, &tmp, &dma_desc, ndesc);
-		get_pad_info((u32 *)&buf_ptr, &buf_len, ndesc);
+		get_sw_data((u32 *)&buf_ptr, &buf_len, ndesc);
 		dma_unmap_page(netcp->dev, dma_buf, PAGE_SIZE, DMA_FROM_DEVICE);
 		__free_page(buf_ptr);
 		knav_pool_desc_put(netcp->rx_pool, desc);
 	}
-	get_pad_info((u32 *)&buf_ptr, &buf_len, desc);
+	get_sw_data((u32 *)&buf_ptr, &buf_len, desc);
 
 	if (buf_ptr)
 		netcp_frag_free(buf_len <= PAGE_SIZE, buf_ptr);
@@ -639,7 +641,7 @@ static int netcp_process_one_rx_packet(struct netcp_intf *netcp)
 	}
 
 	get_pkt_info(&dma_buff, &buf_len, &dma_desc, desc);
-	get_pad_info((u32 *)&org_buf_ptr, &org_buf_len, desc);
+	get_sw_data((u32 *)&org_buf_ptr, &org_buf_len, desc);
 
 	if (unlikely(!org_buf_ptr)) {
 		dev_err(netcp->ndev_dev, "NULL bufptr in desc\n");
@@ -672,7 +674,7 @@ static int netcp_process_one_rx_packet(struct netcp_intf *netcp)
 		}
 
 		get_pkt_info(&dma_buff, &buf_len, &dma_desc, ndesc);
-		get_pad_info((u32 *)&page, &tmp, ndesc);
+		get_sw_data((u32 *)&page, &tmp, ndesc);
 
 		if (likely(dma_buff && buf_len && page)) {
 			dma_unmap_page(netcp->dev, dma_buff, PAGE_SIZE,
@@ -761,7 +763,7 @@ static void netcp_free_rx_buf(struct netcp_intf *netcp, int fdq)
 		}
 
 		get_org_pkt_info(&dma, &buf_len, desc);
-		get_pad_info((u32 *)&buf_ptr, &tmp, desc);
+		get_sw_data((u32 *)&buf_ptr, &tmp, desc);
 
 		if (unlikely(!dma)) {
 			dev_err(netcp->ndev_dev, "NULL orig_buff in desc\n");
@@ -813,7 +815,7 @@ static int netcp_allocate_rx_buf(struct netcp_intf *netcp, int fdq)
 	struct page *page;
 	dma_addr_t dma;
 	void *bufptr;
-	u32 pad[2];
+	u32 sw_data[2];
 
 	/* Allocate descriptor */
 	hwdesc = knav_pool_desc_get(netcp->rx_pool);
@@ -830,7 +832,7 @@ static int netcp_allocate_rx_buf(struct netcp_intf *netcp, int fdq)
 				SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 
 		bufptr = netdev_alloc_frag(primary_buf_len);
-		pad[1] = primary_buf_len;
+		sw_data[1] = primary_buf_len;
 
 		if (unlikely(!bufptr)) {
 			dev_warn_ratelimited(netcp->ndev_dev,
@@ -842,7 +844,7 @@ static int netcp_allocate_rx_buf(struct netcp_intf *netcp, int fdq)
 		if (unlikely(dma_mapping_error(netcp->dev, dma)))
 			goto fail;
 
-		pad[0] = (u32)bufptr;
+		sw_data[0] = (u32)bufptr;
 	} else {
 		/* Allocate a secondary receive queue entry */
 		page = alloc_page(GFP_ATOMIC | GFP_DMA | __GFP_COLD);
@@ -852,8 +854,8 @@ static int netcp_allocate_rx_buf(struct netcp_intf *netcp, int fdq)
 		}
 		buf_len = PAGE_SIZE;
 		dma = dma_map_page(netcp->dev, page, 0, buf_len, DMA_TO_DEVICE);
-		pad[0] = (u32)page;
-		pad[1] = 0;
+		sw_data[0] = (u32)page;
+		sw_data[1] = 0;
 	}
 
 	desc_info =  KNAV_DMA_DESC_PS_INFO_IN_DESC;
@@ -863,7 +865,7 @@ static int netcp_allocate_rx_buf(struct netcp_intf *netcp, int fdq)
 	pkt_info |= (netcp->rx_queue_id & KNAV_DMA_DESC_RETQ_MASK) <<
 		    KNAV_DMA_DESC_RETQ_SHIFT;
 	set_org_pkt_info(dma, buf_len, hwdesc);
-	set_pad_info(pad[0], pad[1], hwdesc);
+	set_sw_data(sw_data[0], sw_data[1], hwdesc);
 	set_desc_info(desc_info, pkt_info, hwdesc);
 
 	/* Push to FDQs */
@@ -969,7 +971,7 @@ static int netcp_process_tx_compl_packets(struct netcp_intf *netcp,
 			continue;
 		}
 
-		get_pad_info((u32 *)&skb, &tmp, desc);
+		get_sw_data((u32 *)&skb, &tmp, desc);
 		netcp_free_tx_desc_chain(netcp, desc, dma_sz);
 		if (!skb) {
 			dev_err(netcp->ndev_dev, "No skb in Tx desc\n");
@@ -1174,7 +1176,7 @@ static int netcp_tx_submit_skb(struct netcp_intf *netcp,
 	}
 
 	set_words(&tmp, 1, &desc->packet_info);
-	set_words((u32 *)&skb, 1, &desc->pad[0]);
+	set_words((u32 *)&skb, 1, &desc->sw_data[0]);
 
 	if (tx_pipe->flags & SWITCH_TO_PORT_IN_TAGINFO) {
 		tmp = tx_pipe->switch_to_port;
-- 
1.9.1

[PATCH v1 4/4] net: netcp: rework the code for get/set sw_data in dma desc

[Murali Karicheri]

SW data field in descriptor can be used by software to hold private
data for the driver. As there are 4 words available for this purpose,
use separate macros to place it or retrieve the same to/from
descriptors. Also do type cast of data types accordingly.

Cc: Wingman Kwok <w-kwok2@ti.com>
Cc: Mugunthan V N <mugunthanvnm@ti.com>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Grygorii Strashko <grygorii.strashko@ti.com>
CC: David Laight <David.Laight@ACULAB.COM>
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
---
 v1 - new patch based on discussion at
      https://patchwork.ozlabs.org/patch/580860/
 drivers/net/ethernet/ti/netcp_core.c | 43 ++++++++++++++++++++++--------------
 1 file changed, 27 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/ti/netcp_core.c b/drivers/net/ethernet/ti/netcp_core.c
index 1d07cca..8b353e4 100644
--- a/drivers/net/ethernet/ti/netcp_core.c
+++ b/drivers/net/ethernet/ti/netcp_core.c
@@ -117,13 +117,18 @@ static void get_pkt_info(dma_addr_t *buff, u32 *buff_len, dma_addr_t *ndesc,
 	*ndesc = le32_to_cpu(desc->next_desc);
 }
 
-static void get_sw_data(u32 *data0, u32 *data1, struct knav_dma_desc *desc)
+static u32 get_sw_data(int index, struct knav_dma_desc *desc)
 {
 	/* No Endian conversion needed as this data is untouched by hw */
-	*data0 = desc->sw_data[0];
-	*data1 = desc->sw_data[1];
+	return desc->sw_data[index];
 }
 
+/* use these macros to get sw data */
+#define GET_SW_DATA0(desc) get_sw_data(0, desc)
+#define GET_SW_DATA1(desc) get_sw_data(1, desc)
+#define GET_SW_DATA2(desc) get_sw_data(2, desc)
+#define GET_SW_DATA3(desc) get_sw_data(3, desc)
+
 static void get_org_pkt_info(dma_addr_t *buff, u32 *buff_len,
 			     struct knav_dma_desc *desc)
 {
@@ -154,13 +159,18 @@ static void set_desc_info(u32 desc_info, u32 pkt_info,
 	desc->packet_info = cpu_to_le32(pkt_info);
 }
 
-static void set_sw_data(u32 data0, u32 data1, struct knav_dma_desc *desc)
+static void set_sw_data(int index, u32 data, struct knav_dma_desc *desc)
 {
 	/* No Endian conversion needed as this data is untouched by hw */
-	desc->sw_data[0] = data0;
-	desc->sw_data[1] = data1;
+	desc->sw_data[index] = data;
 }
 
+/* use these macros to set sw data */
+#define SET_SW_DATA0(data, desc) set_sw_data(0, data, desc)
+#define SET_SW_DATA1(data, desc) set_sw_data(1, data, desc)
+#define SET_SW_DATA2(data, desc) set_sw_data(2, data, desc)
+#define SET_SW_DATA3(data, desc) set_sw_data(3, data, desc)
+
 static void set_org_pkt_info(dma_addr_t buff, u32 buff_len,
 			     struct knav_dma_desc *desc)
 {
@@ -583,12 +593,14 @@ static void netcp_free_rx_desc_chain(struct netcp_intf *netcp,
 			break;
 		}
 		get_pkt_info(&dma_buf, &tmp, &dma_desc, ndesc);
-		get_sw_data((u32 *)&buf_ptr, &buf_len, ndesc);
+		buf_ptr = (void *)GET_SW_DATA0(ndesc);
+		buf_len = (int)GET_SW_DATA1(desc);
 		dma_unmap_page(netcp->dev, dma_buf, PAGE_SIZE, DMA_FROM_DEVICE);
 		__free_page(buf_ptr);
 		knav_pool_desc_put(netcp->rx_pool, desc);
 	}
-	get_sw_data((u32 *)&buf_ptr, &buf_len, desc);
+	buf_ptr = (void *)GET_SW_DATA0(desc);
+	buf_len = (int)GET_SW_DATA1(desc);
 
 	if (buf_ptr)
 		netcp_frag_free(buf_len <= PAGE_SIZE, buf_ptr);
@@ -628,7 +640,6 @@ static int netcp_process_one_rx_packet(struct netcp_intf *netcp)
 	struct netcp_packet p_info;
 	struct sk_buff *skb;
 	void *org_buf_ptr;
-	u32 tmp;
 
 	dma_desc = knav_queue_pop(netcp->rx_queue, &dma_sz);
 	if (!dma_desc)
@@ -641,7 +652,8 @@ static int netcp_process_one_rx_packet(struct netcp_intf *netcp)
 	}
 
 	get_pkt_info(&dma_buff, &buf_len, &dma_desc, desc);
-	get_sw_data((u32 *)&org_buf_ptr, &org_buf_len, desc);
+	org_buf_ptr = (void *)GET_SW_DATA0(desc);
+	org_buf_len = (int)GET_SW_DATA1(desc);
 
 	if (unlikely(!org_buf_ptr)) {
 		dev_err(netcp->ndev_dev, "NULL bufptr in desc\n");
@@ -674,7 +686,7 @@ static int netcp_process_one_rx_packet(struct netcp_intf *netcp)
 		}
 
 		get_pkt_info(&dma_buff, &buf_len, &dma_desc, ndesc);
-		get_sw_data((u32 *)&page, &tmp, ndesc);
+		page = (struct page *)GET_SW_DATA0(desc);
 
 		if (likely(dma_buff && buf_len && page)) {
 			dma_unmap_page(netcp->dev, dma_buff, PAGE_SIZE,
@@ -752,7 +764,6 @@ static void netcp_free_rx_buf(struct netcp_intf *netcp, int fdq)
 	unsigned int buf_len, dma_sz;
 	dma_addr_t dma;
 	void *buf_ptr;
-	u32 tmp;
 
 	/* Allocate descriptor */
 	while ((dma = knav_queue_pop(netcp->rx_fdq[fdq], &dma_sz))) {
@@ -763,7 +774,7 @@ static void netcp_free_rx_buf(struct netcp_intf *netcp, int fdq)
 		}
 
 		get_org_pkt_info(&dma, &buf_len, desc);
-		get_sw_data((u32 *)&buf_ptr, &tmp, desc);
+		buf_ptr = (void *)GET_SW_DATA0(desc);
 
 		if (unlikely(!dma)) {
 			dev_err(netcp->ndev_dev, "NULL orig_buff in desc\n");
@@ -865,7 +876,8 @@ static int netcp_allocate_rx_buf(struct netcp_intf *netcp, int fdq)
 	pkt_info |= (netcp->rx_queue_id & KNAV_DMA_DESC_RETQ_MASK) <<
 		    KNAV_DMA_DESC_RETQ_SHIFT;
 	set_org_pkt_info(dma, buf_len, hwdesc);
-	set_sw_data(sw_data[0], sw_data[1], hwdesc);
+	SET_SW_DATA0(sw_data[0], hwdesc);
+	SET_SW_DATA1(sw_data[1], hwdesc);
 	set_desc_info(desc_info, pkt_info, hwdesc);
 
 	/* Push to FDQs */
@@ -958,7 +970,6 @@ static int netcp_process_tx_compl_packets(struct netcp_intf *netcp,
 	unsigned int dma_sz;
 	dma_addr_t dma;
 	int pkts = 0;
-	u32 tmp;
 
 	while (budget--) {
 		dma = knav_queue_pop(netcp->tx_compl_q, &dma_sz);
@@ -971,7 +982,7 @@ static int netcp_process_tx_compl_packets(struct netcp_intf *netcp,
 			continue;
 		}
 
-		get_sw_data((u32 *)&skb, &tmp, desc);
+		skb = (struct sk_buff *)GET_SW_DATA0(desc);
 		netcp_free_tx_desc_chain(netcp, desc, dma_sz);
 		if (!skb) {
 			dev_err(netcp->ndev_dev, "No skb in Tx desc\n");
-- 
1.9.1

Re: [PATCH v1 2/4] soc: ti: knav_dma: rename pad in struct knav_dma_desc to sw_data

[Arnd Bergmann]

On Thursday 18 February 2016 14:46:15 Murali Karicheri wrote:
> Rename the pad to sw_data as per description of this field in the hardware
> spec(refer sprugr9 from www.ti.com). Latest version of the document is
> at http://www.ti.com/lit/ug/sprugr9h/sprugr9h.pdf and section 3.1
> Host Packet Descriptor describes this field.
> 
> Also define and use a constant for the size of sw_data field similar to
> other fields in the struct for desc and document the sw_data field
> in the header. As the sw_data is not touched by hw, it's type can be
> changed to u32.
> 
> 

Acked-by: Arnd Bergmann <arnd@arndb.de>

Re: [PATCH v1 3/4] net: netcp: rename {get/set}pad_info to {get/set}_sw_data

[Arnd Bergmann]

On Thursday 18 February 2016 14:46:16 Murali Karicheri wrote:
> Rename the helpers to match with the updated dma desc field sw_data.
> 
> Cc: Wingman Kwok <w-kwok2@ti.com>
> Cc: Mugunthan V N <mugunthanvnm@ti.com>
> CC: Arnd Bergmann <arnd@arndb.de>
> CC: Grygorii Strashko <grygorii.strashko@ti.com>
> CC: David Laight <David.Laight@ACULAB.COM>
> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
> ---
>  v1 - new patch to based on discussion at
> 	https://patchwork.ozlabs.org/patch/580860/
>  drivers/net/ethernet/ti/netcp_core.c | 40 +++++++++++++++++++-----------------
>  1 file changed, 21 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/net/ethernet/ti/netcp_core.c b/drivers/net/ethernet/ti/netcp_core.c
> index 0b26e52..1d07cca 100644
> --- a/drivers/net/ethernet/ti/netcp_core.c
> +++ b/drivers/net/ethernet/ti/netcp_core.c
> @@ -117,10 +117,11 @@ static void get_pkt_info(dma_addr_t *buff, u32 *buff_len, dma_addr_t *ndesc,
>  	*ndesc = le32_to_cpu(desc->next_desc);
>  }
>  
> -static void get_pad_info(u32 *pad0, u32 *pad1, struct knav_dma_desc *desc)
> +static void get_sw_data(u32 *data0, u32 *data1, struct knav_dma_desc *desc)
>  {
> -	*pad0 = le32_to_cpu(desc->pad[0]);
> -	*pad1 = le32_to_cpu(desc->pad[1]);
> +	/* No Endian conversion needed as this data is untouched by hw */
> +	*data0 = desc->sw_data[0];
> +	*data1 = desc->sw_data[1];
>  }

Actually this needs to be done together with patch 2, or you
get a build failure if this one is not yet applied.

> @@ -1174,7 +1176,7 @@ static int netcp_tx_submit_skb(struct netcp_intf *netcp,
>  	}
>  
>  	set_words(&tmp, 1, &desc->packet_info);
> -	set_words((u32 *)&skb, 1, &desc->pad[0]);
> +	set_words((u32 *)&skb, 1, &desc->sw_data[0]);
>  
>  	if (tx_pipe->flags & SWITCH_TO_PORT_IN_TAGINFO) {
>  		tmp = tx_pipe->switch_to_port;
> 

This seems to introduce a bug, and should produce an "sparse" warning
about a u32 being passed into a function expecting a __le32.

The other bug I originally tried to address here is the way an indirect
pointer is converted to a 'u32' pointer, which won't work on 64-bit
architectures when pointers are wider than u32. Maybe at least put a
comment here that this is a known deficiency.

	Arnd

Re: [PATCH v1 1/4] net: ti: netcp: restore get/set_pad_info() functionality

[Arnd Bergmann]

On Thursday 18 February 2016 14:46:14 Murali Karicheri wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> The commit 899077791403 ("netcp: try to reduce type confusion in
> descriptors") introduces a regression in Kernel 4.5-rc1 and it breaks
> get/set_pad_info() functionality.
> 
> The TI NETCP driver uses pad0 and pad1 fields of knav_dma_desc to
> store DMA/MEM buffer pointer and buffer size respectively. And in both
> cases for Keystone 2 the pointer type size is 32 bit regardless of
> LAPE enabled or not, because CONFIG_ARCH_DMA_ADDR_T_64BIT originally
> is not expected to be defined.
> 
> 			!LAPE	LPAE
> sizeof(void*)		32bit	32bit
> sizeof(dma_addr_t) 	32bit	32bit
> sizeof(phys_addr_t) 	32bit	64bit

As this was never relevant or true, I don't think it needs to be
mentioned here, it just confuses things. Please just assume that
dma_addr_t can be 64-bit wide, but will only contain 32-bit
numbers on keystone.

> Unfortunately, above commit changed buffer's pointers save/restore
> code (get/set_pad_info()) and added intermediate conversation to u64
> which works incorrectly on 32bit Keystone 2 and causes TI NETCP driver
> crash in RX/TX path due to "Unable to handle kernel NULL pointer"
> exception. This issue was reported and discussed in [1].

Have you been able to figure out why it actually broke? I'd still
like to know.

> Hence, fix it by partially reverting above commit and restoring
> get/set_pad_info() functionality as it was before.
> 
> [1] https://www.mail-archive.com/netdev@vger.kernel.org/msg95361.html
> Cc: Wingman Kwok <w-kwok2@ti.com>
> Cc: Mugunthan V N <mugunthanvnm@ti.com>
> CC: David Laight <David.Laight@ACULAB.COM>
> Reported-by: Franklin S Cooper Jr <fcooper@ti.com>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>

I don't think I sent this patch with a 'Signed-off-by', did I?
(I could be misremembering that).

	Arnd

Re: [PATCH v1 1/4] net: ti: netcp: restore get/set_pad_info() functionality

[Murali Karicheri]

On 02/19/2016 09:41 AM, Arnd Bergmann wrote:
> On Thursday 18 February 2016 14:46:14 Murali Karicheri wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>>
>> The commit 899077791403 ("netcp: try to reduce type confusion in
>> descriptors") introduces a regression in Kernel 4.5-rc1 and it breaks
>> get/set_pad_info() functionality.
>>
>> The TI NETCP driver uses pad0 and pad1 fields of knav_dma_desc to
>> store DMA/MEM buffer pointer and buffer size respectively. And in both
>> cases for Keystone 2 the pointer type size is 32 bit regardless of
>> LAPE enabled or not, because CONFIG_ARCH_DMA_ADDR_T_64BIT originally
>> is not expected to be defined.
>>
>> 			!LAPE	LPAE
>> sizeof(void*)		32bit	32bit
>> sizeof(dma_addr_t) 	32bit	32bit
>> sizeof(phys_addr_t) 	32bit	64bit
> 
> As this was never relevant or true, I don't think it needs to be
> mentioned here, it just confuses things. Please just assume that
> dma_addr_t can be 64-bit wide, but will only contain 32-bit
> numbers on keystone.
> 

I can remove this from the commit description and re-send.

>> Unfortunately, above commit changed buffer's pointers save/restore
>> code (get/set_pad_info()) and added intermediate conversation to u64
>> which works incorrectly on 32bit Keystone 2 and causes TI NETCP driver
>> crash in RX/TX path due to "Unable to handle kernel NULL pointer"
>> exception. This issue was reported and discussed in [1].
> 
> Have you been able to figure out why it actually broke? I'd still
> like to know.
> 
As Grygorii is out of office until Monday, I would like to step in.
I will take some time today to try review the reverted changes for
failure reason and get back. But as you have agreed in the discussion
at https://www.mail-archive.com/netdev@vger.kernel.org/msg96311.html
Can we fix the regression by applying this patch and rest of the series
if it looks good? If I need to separate this from rest of the series,
let me know and I can take care of that.

>> Hence, fix it by partially reverting above commit and restoring
>> get/set_pad_info() functionality as it was before.
>>
>> [1] https://www.mail-archive.com/netdev@vger.kernel.org/msg95361.html
>> Cc: Wingman Kwok <w-kwok2@ti.com>
>> Cc: Mugunthan V N <mugunthanvnm@ti.com>
>> CC: David Laight <David.Laight@ACULAB.COM>
>> Reported-by: Franklin S Cooper Jr <fcooper@ti.com>
>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
>> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
> 
> I don't think I sent this patch with a 'Signed-off-by', did I?
> (I could be misremembering that).
> 

I think you had agreed based on what I read at
https://www.mail-archive.com/netdev@vger.kernel.org/msg96311.html

reproduced below for your convenience.
=============================================================================

> What I could do now is update your/my patch as i mentioned in [1]
> and re-send it at the weekend (with your authorship and my signoff).
> Do you agree?
> 
> 
> [1] https://www.mail-archive.com/netdev@vger.kernel.org/msg95831.html

Yes, let's do that in the meantime. I can also make sure that that
the driver doesn't build on 64-bit, just in case.
=============================================================================

Hope I can keep your sign-off when I re-send this. Please confirm.

Murali

> 	Arnd
> 


-- 
Murali Karicheri
Linux Kernel, Keystone

Re: [PATCH v1 1/4] net: ti: netcp: restore get/set_pad_info() functionality

[Arnd Bergmann]

On Friday 19 February 2016 10:48:30 Murali Karicheri wrote:
> On 02/19/2016 09:41 AM, Arnd Bergmann wrote:
> > On Thursday 18 February 2016 14:46:14 Murali Karicheri wrote:
> >> From: Arnd Bergmann <arnd@arndb.de>
> >>
> >> The commit 899077791403 ("netcp: try to reduce type confusion in
> >> descriptors") introduces a regression in Kernel 4.5-rc1 and it breaks
> >> get/set_pad_info() functionality.
> >>
> >> The TI NETCP driver uses pad0 and pad1 fields of knav_dma_desc to
> >> store DMA/MEM buffer pointer and buffer size respectively. And in both
> >> cases for Keystone 2 the pointer type size is 32 bit regardless of
> >> LAPE enabled or not, because CONFIG_ARCH_DMA_ADDR_T_64BIT originally
> >> is not expected to be defined.
> >>
> >>                      !LAPE   LPAE
> >> sizeof(void*)                32bit   32bit
> >> sizeof(dma_addr_t)   32bit   32bit
> >> sizeof(phys_addr_t)  32bit   64bit
> > 
> > As this was never relevant or true, I don't think it needs to be
> > mentioned here, it just confuses things. Please just assume that
> > dma_addr_t can be 64-bit wide, but will only contain 32-bit
> > numbers on keystone.
> > 
> 
> I can remove this from the commit description and re-send.

Ok

> >> Unfortunately, above commit changed buffer's pointers save/restore
> >> code (get/set_pad_info()) and added intermediate conversation to u64
> >> which works incorrectly on 32bit Keystone 2 and causes TI NETCP driver
> >> crash in RX/TX path due to "Unable to handle kernel NULL pointer"
> >> exception. This issue was reported and discussed in [1].
> > 
> > Have you been able to figure out why it actually broke? I'd still
> > like to know.
> > 
> As Grygorii is out of office until Monday, I would like to step in.
> I will take some time today to try review the reverted changes for
> failure reason and get back. But as you have agreed in the discussion
> at https://www.mail-archive.com/netdev@vger.kernel.org/msg96311.html
> Can we fix the regression by applying this patch and rest of the series
> if it looks good? If I need to separate this from rest of the series,
> let me know and I can take care of that.

Yes, sounds fine.

> >> Hence, fix it by partially reverting above commit and restoring
> >> get/set_pad_info() functionality as it was before.
> >>
> >> [1] https://www.mail-archive.com/netdev@vger.kernel.org/msg95361.html
> >> Cc: Wingman Kwok <w-kwok2@ti.com>
> >> Cc: Mugunthan V N <mugunthanvnm@ti.com>
> >> CC: David Laight <David.Laight@ACULAB.COM>
> >> Reported-by: Franklin S Cooper Jr <fcooper@ti.com>
> >> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> >> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
> >> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
> > 
> > I don't think I sent this patch with a 'Signed-off-by', did I?
> > (I could be misremembering that).
> > 
> 
> I think you had agreed based on what I read at
> https://www.mail-archive.com/netdev@vger.kernel.org/msg96311.html
> 
> reproduced below for your convenience.
> =============================================================================
> 
> > What I could do now is update your/my patch as i mentioned in [1]
> > and re-send it at the weekend (with your authorship and my signoff).
> > Do you agree?
> > 
> > 
> > [1] https://www.mail-archive.com/netdev@vger.kernel.org/msg95831.html
> 
> Yes, let's do that in the meantime. I can also make sure that that
> the driver doesn't build on 64-bit, just in case.
> =============================================================================
> 
> Hope I can keep your sign-off when I re-send this. Please confirm.

The most important part here is that you don't add a "Signed-off-by"
tag unless it was provided by that person as part of the submission.

I'm slightly uncomfortable with having my Signed-off-by as the first
one when I did not write the changelog myself, so I'd prefer if
you just add my Acked-by once I provide that. If that doesn't
work for you, let's follow up in private to sort it out.

	Arnd

Re: [PATCH v1 1/4] net: ti: netcp: restore get/set_pad_info() functionality

[Murali Karicheri]

On 02/19/2016 11:41 AM, Arnd Bergmann wrote:
> On Friday 19 February 2016 10:48:30 Murali Karicheri wrote:
>> On 02/19/2016 09:41 AM, Arnd Bergmann wrote:
>>> On Thursday 18 February 2016 14:46:14 Murali Karicheri wrote:
>>>> From: Arnd Bergmann <arnd@arndb.de>
>>>>
>>>> The commit 899077791403 ("netcp: try to reduce type confusion in
>>>> descriptors") introduces a regression in Kernel 4.5-rc1 and it breaks
>>>> get/set_pad_info() functionality.
>>>>
>>>> The TI NETCP driver uses pad0 and pad1 fields of knav_dma_desc to
>>>> store DMA/MEM buffer pointer and buffer size respectively. And in both
>>>> cases for Keystone 2 the pointer type size is 32 bit regardless of
>>>> LAPE enabled or not, because CONFIG_ARCH_DMA_ADDR_T_64BIT originally
>>>> is not expected to be defined.
>>>>
>>>>                      !LAPE   LPAE
>>>> sizeof(void*)                32bit   32bit
>>>> sizeof(dma_addr_t)   32bit   32bit
>>>> sizeof(phys_addr_t)  32bit   64bit
>>>
>>> As this was never relevant or true, I don't think it needs to be
>>> mentioned here, it just confuses things. Please just assume that
>>> dma_addr_t can be 64-bit wide, but will only contain 32-bit
>>> numbers on keystone.
>>>
>>
>> I can remove this from the commit description and re-send.
> 
> Ok
> 
>>>> Unfortunately, above commit changed buffer's pointers save/restore
>>>> code (get/set_pad_info()) and added intermediate conversation to u64
>>>> which works incorrectly on 32bit Keystone 2 and causes TI NETCP driver
>>>> crash in RX/TX path due to "Unable to handle kernel NULL pointer"
>>>> exception. This issue was reported and discussed in [1].
>>>
>>> Have you been able to figure out why it actually broke? I'd still
>>> like to know.
>>>
>> As Grygorii is out of office until Monday, I would like to step in.
>> I will take some time today to try review the reverted changes for
>> failure reason and get back. But as you have agreed in the discussion
>> at https://www.mail-archive.com/netdev@vger.kernel.org/msg96311.html
>> Can we fix the regression by applying this patch and rest of the series
>> if it looks good? If I need to separate this from rest of the series,
>> let me know and I can take care of that.
> 
> Yes, sounds fine.
> 
>>>> Hence, fix it by partially reverting above commit and restoring
>>>> get/set_pad_info() functionality as it was before.
>>>>
>>>> [1] https://www.mail-archive.com/netdev@vger.kernel.org/msg95361.html
>>>> Cc: Wingman Kwok <w-kwok2@ti.com>
>>>> Cc: Mugunthan V N <mugunthanvnm@ti.com>
>>>> CC: David Laight <David.Laight@ACULAB.COM>
>>>> Reported-by: Franklin S Cooper Jr <fcooper@ti.com>
>>>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>>>> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
>>>> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
>>>
>>> I don't think I sent this patch with a 'Signed-off-by', did I?
>>> (I could be misremembering that).
>>>
>>
>> I think you had agreed based on what I read at
>> https://www.mail-archive.com/netdev@vger.kernel.org/msg96311.html
>>
>> reproduced below for your convenience.
>> =============================================================================
>>
>>> What I could do now is update your/my patch as i mentioned in [1]
>>> and re-send it at the weekend (with your authorship and my signoff).
>>> Do you agree?
>>>
>>>
>>> [1] https://www.mail-archive.com/netdev@vger.kernel.org/msg95831.html
>>
>> Yes, let's do that in the meantime. I can also make sure that that
>> the driver doesn't build on 64-bit, just in case.
>> =============================================================================
>>
>> Hope I can keep your sign-off when I re-send this. Please confirm.
> 
> The most important part here is that you don't add a "Signed-off-by"
> tag unless it was provided by that person as part of the submission.
> 
> I'm slightly uncomfortable with having my Signed-off-by as the first
> one when I did not write the changelog myself, so I'd prefer if
> you just add my Acked-by once I provide that. If that doesn't
> work for you, let's follow up in private to sort it out.
> 
Ok. I will remove it.

> 	Arnd
> 


-- 
Murali Karicheri
Linux Kernel, Keystone

Re: [PATCH v1 3/4] net: netcp: rename {get/set}pad_info to {get/set}_sw_data

[Murali Karicheri]

On 02/19/2016 09:37 AM, Arnd Bergmann wrote:
> On Thursday 18 February 2016 14:46:16 Murali Karicheri wrote:
>> Rename the helpers to match with the updated dma desc field sw_data.
>>
>> Cc: Wingman Kwok <w-kwok2@ti.com>
>> Cc: Mugunthan V N <mugunthanvnm@ti.com>
>> CC: Arnd Bergmann <arnd@arndb.de>
>> CC: Grygorii Strashko <grygorii.strashko@ti.com>
>> CC: David Laight <David.Laight@ACULAB.COM>
>> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
>> ---
>>  v1 - new patch to based on discussion at
>> 	https://patchwork.ozlabs.org/patch/580860/
>>  drivers/net/ethernet/ti/netcp_core.c | 40 +++++++++++++++++++-----------------
>>  1 file changed, 21 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/ti/netcp_core.c b/drivers/net/ethernet/ti/netcp_core.c
>> index 0b26e52..1d07cca 100644
>> --- a/drivers/net/ethernet/ti/netcp_core.c
>> +++ b/drivers/net/ethernet/ti/netcp_core.c
>> @@ -117,10 +117,11 @@ static void get_pkt_info(dma_addr_t *buff, u32 *buff_len, dma_addr_t *ndesc,
>>  	*ndesc = le32_to_cpu(desc->next_desc);
>>  }
>>  
>> -static void get_pad_info(u32 *pad0, u32 *pad1, struct knav_dma_desc *desc)
>> +static void get_sw_data(u32 *data0, u32 *data1, struct knav_dma_desc *desc)
>>  {
>> -	*pad0 = le32_to_cpu(desc->pad[0]);
>> -	*pad1 = le32_to_cpu(desc->pad[1]);
>> +	/* No Endian conversion needed as this data is untouched by hw */
>> +	*data0 = desc->sw_data[0];
>> +	*data1 = desc->sw_data[1];
>>  }
> 
> Actually this needs to be done together with patch 2, or you
> get a build failure if this one is not yet applied.
I have realized that. Only reason was that it belongs to drivers/soc which is
merged through Santosh. I will combine it and re-send.
> 
>> @@ -1174,7 +1176,7 @@ static int netcp_tx_submit_skb(struct netcp_intf *netcp,
>>  	}
>>  
>>  	set_words(&tmp, 1, &desc->packet_info);
>> -	set_words((u32 *)&skb, 1, &desc->pad[0]);
>> +	set_words((u32 *)&skb, 1, &desc->sw_data[0]);
>>  
>>  	if (tx_pipe->flags & SWITCH_TO_PORT_IN_TAGINFO) {
>>  		tmp = tx_pipe->switch_to_port;
>>
> 
> This seems to introduce a bug, and should produce an "sparse" warning
> about a u32 being passed into a function expecting a __le32.
> 
Ahah, this was changed recently. I will take a look.

> The other bug I originally tried to address here is the way an indirect
> pointer is converted to a 'u32' pointer, which won't work on 64-bit
> architectures when pointers are wider than u32. Maybe at least put a
> comment here that this is a known deficiency.
> 
Ok. Let me check and respond.

> 	Arnd
> 


-- 
Murali Karicheri
Linux Kernel, Keystone

Re: [PATCH v1 3/4] net: netcp: rename {get/set}pad_info to {get/set}_sw_data

[Murali Karicheri]

On 02/19/2016 09:37 AM, Arnd Bergmann wrote:
> On Thursday 18 February 2016 14:46:16 Murali Karicheri wrote:
>> Rename the helpers to match with the updated dma desc field sw_data.
>>
>> Cc: Wingman Kwok <w-kwok2@ti.com>
>> Cc: Mugunthan V N <mugunthanvnm@ti.com>
>> CC: Arnd Bergmann <arnd@arndb.de>
>> CC: Grygorii Strashko <grygorii.strashko@ti.com>
>> CC: David Laight <David.Laight@ACULAB.COM>
>> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
>> ---
>>  v1 - new patch to based on discussion at
>> 	https://patchwork.ozlabs.org/patch/580860/
>>  drivers/net/ethernet/ti/netcp_core.c | 40 +++++++++++++++++++-----------------
>>  1 file changed, 21 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/ti/netcp_core.c b/drivers/net/ethernet/ti/netcp_core.c
>> index 0b26e52..1d07cca 100644
>> --- a/drivers/net/ethernet/ti/netcp_core.c
>> +++ b/drivers/net/ethernet/ti/netcp_core.c
>> @@ -117,10 +117,11 @@ static void get_pkt_info(dma_addr_t *buff, u32 *buff_len, dma_addr_t *ndesc,
>>  	*ndesc = le32_to_cpu(desc->next_desc);
>>  }
>>  
>> -static void get_pad_info(u32 *pad0, u32 *pad1, struct knav_dma_desc *desc)
>> +static void get_sw_data(u32 *data0, u32 *data1, struct knav_dma_desc *desc)
>>  {
>> -	*pad0 = le32_to_cpu(desc->pad[0]);
>> -	*pad1 = le32_to_cpu(desc->pad[1]);
>> +	/* No Endian conversion needed as this data is untouched by hw */
>> +	*data0 = desc->sw_data[0];
>> +	*data1 = desc->sw_data[1];
>>  }
> 
> Actually this needs to be done together with patch 2, or you
> get a build failure if this one is not yet applied.
> 
>> @@ -1174,7 +1176,7 @@ static int netcp_tx_submit_skb(struct netcp_intf *netcp,
>>  	}
>>  
>>  	set_words(&tmp, 1, &desc->packet_info);
>> -	set_words((u32 *)&skb, 1, &desc->pad[0]);
>> +	set_words((u32 *)&skb, 1, &desc->sw_data[0]);
>>  
>>  	if (tx_pipe->flags & SWITCH_TO_PORT_IN_TAGINFO) {
>>  		tmp = tx_pipe->switch_to_port;
>>
> 
> This seems to introduce a bug, and should produce an "sparse" warning
> about a u32 being passed into a function expecting a __le32.
> 
The fix is to use set_sw_data() instead. I could reproduce the sparse
warning you mentioned and fixed using the above. Will be part of v2.

> The other bug I originally tried to address here is the way an indirect
> pointer is converted to a 'u32' pointer, which won't work on 64-bit
> architectures when pointers are wider than u32. Maybe at least put a
> comment here that this is a known deficiency.

Will add a comment here and other possible places we do similar things as
much as I can.

Murali

> 
> 	Arnd
> 


-- 
Murali Karicheri
Linux Kernel, Keystone

Re: [PATCH v1 1/4] net: ti: netcp: restore get/set_pad_info() functionality

[Murali Karicheri]

On 02/19/2016 09:41 AM, Arnd Bergmann wrote:
> On Thursday 18 February 2016 14:46:14 Murali Karicheri wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>>
>> The commit 899077791403 ("netcp: try to reduce type confusion in
>> descriptors") introduces a regression in Kernel 4.5-rc1 and it breaks
>> get/set_pad_info() functionality.
>>
>> The TI NETCP driver uses pad0 and pad1 fields of knav_dma_desc to
>> store DMA/MEM buffer pointer and buffer size respectively. And in both
>> cases for Keystone 2 the pointer type size is 32 bit regardless of
>> LAPE enabled or not, because CONFIG_ARCH_DMA_ADDR_T_64BIT originally
>> is not expected to be defined.
>>
>> 			!LAPE	LPAE
>> sizeof(void*)		32bit	32bit
>> sizeof(dma_addr_t) 	32bit	32bit
>> sizeof(phys_addr_t) 	32bit	64bit
> 
> As this was never relevant or true, I don't think it needs to be
> mentioned here, it just confuses things. Please just assume that
> dma_addr_t can be 64-bit wide, but will only contain 32-bit
> numbers on keystone.
> 
>> Unfortunately, above commit changed buffer's pointers save/restore
>> code (get/set_pad_info()) and added intermediate conversation to u64
>> which works incorrectly on 32bit Keystone 2 and causes TI NETCP driver
>> crash in RX/TX path due to "Unable to handle kernel NULL pointer"
>> exception. This issue was reported and discussed in [1].
> 
> Have you been able to figure out why it actually broke? I'd still
> like to know.
> 
I have just send v2. I will investigate your original patch that added
regression this afternoon and respond with my observation as soon as
my investigation is complete. I assume, you are trying to make the change
such that the virtual pointers stored in sw_data/pad works across
32bit and 64bit machine, right? 

Murali

>> Hence, fix it by partially reverting above commit and restoring
>> get/set_pad_info() functionality as it was before.
>>
>> [1] https://www.mail-archive.com/netdev@vger.kernel.org/msg95361.html
>> Cc: Wingman Kwok <w-kwok2@ti.com>
>> Cc: Mugunthan V N <mugunthanvnm@ti.com>
>> CC: David Laight <David.Laight@ACULAB.COM>
>> Reported-by: Franklin S Cooper Jr <fcooper@ti.com>
>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
>> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
> 
> I don't think I sent this patch with a 'Signed-off-by', did I?
> (I could be misremembering that).
> 
> 	Arnd
> 


-- 
Murali Karicheri
Linux Kernel, Keystone

Re: [PATCH v1 1/4] net: ti: netcp: restore get/set_pad_info() functionality

[Arnd Bergmann]

On Friday 19 February 2016 13:01:59 Murali Karicheri wrote:
> > 
> I have just send v2. I will investigate your original patch that added
> regression this afternoon and respond with my observation as soon as
> my investigation is complete.

Thanks.

> I assume, you are trying to make the change
> such that the virtual pointers stored in sw_data/pad works across
> 32bit and 64bit machine, right? 

Yes, that was the idea. The way I intended it, pointers were supposed
to always get stored in a pair of swdata fields and take up 64 bits,
independent of the architecture.

	Arnd