stmmac: re-work the internal GMAC DMA platf parameters

This patch re-works the internal GMAC DMA parameters
passed from the platform.
In the past, we only passed the pbl but, with new core,
other parameters can be passed and are mandatory on some
platforms.

New parameters are documented in stmmac.txt because this
patch has an impact for many platforms.

Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
Signed-off-by: Deepak Sikri <deepak.sikri@st.com>
Hacked-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/stmmac.txt

@@ -111,7 +111,7 @@ and detailed below as well:
 	int phy_addr;
 	int interface;
 	struct stmmac_mdio_bus_data *mdio_bus_data;
-	int pbl;
+	struct stmmac_dma_cfg *dma_cfg;
 	int clk_csr;
 	int has_gmac;
 	int enh_desc;
@@ -163,7 +163,7 @@ Where:
  o custom_cfg: this is a custom configuration that can be passed while
 	      initialising the resources.
 
-The we have:
+For MDIO bus The we have:
 
  struct stmmac_mdio_bus_data {
 	int bus_id;
@@ -180,10 +180,28 @@ Where:
  o irqs: list of IRQs, one per PHY.
  o probed_phy_irq: if irqs is NULL, use this for probed PHY.
 
+
+For DMA engine we have the following internal fields that should be
+tuned according to the HW capabilities.
+
+struct stmmac_dma_cfg {
+	int pbl;
+	int fixed_burst;
+	int burst_len_supported;
+};
+
+Where:
+ o pbl: Programmable Burst Length
+ o fixed_burst: program the DMA to use the fixed burst mode
+ o burst_len: this is the value we put in the register
+	      supported values are provided as macros in
+	      linux/stmmac.h header file.
+
+---
+
 Below an example how the structures above are using on ST platforms.
 
  static struct plat_stmmacenet_data stxYYY_ethernet_platform_data = {
-	.pbl = 32,
 	.has_gmac = 0,
 	.enh_desc = 0,
 	.fix_mac_speed = stxYYY_ethernet_fix_mac_speed,

drivers/net/ethernet/stmicro/stmmac/common.h

@@ -236,7 +236,8 @@ struct stmmac_desc_ops {
 
 struct stmmac_dma_ops {
 	/* DMA core initialization */
-	int (*init) (void __iomem *ioaddr, int pbl, u32 dma_tx, u32 dma_rx);
+	int (*init) (void __iomem *ioaddr, int pbl, int fb, int burst_len,
+			u32 dma_tx, u32 dma_rx);
 	/* Dump DMA registers */
 	void (*dump_regs) (void __iomem *ioaddr);
 	/* Set tx/rx threshold in the csr6 register

drivers/net/ethernet/stmicro/stmmac/dwmac1000.h

@@ -142,7 +142,7 @@ enum rx_tx_priority_ratio {
 #define DMA_BUS_MODE_RPBL_MASK	0x003e0000	/* Rx-Programmable Burst Len */
 #define DMA_BUS_MODE_RPBL_SHIFT	17
 #define DMA_BUS_MODE_USP	0x00800000
-#define DMA_BUS_MODE_4PBL	0x01000000
+#define DMA_BUS_MODE_PBL	0x01000000
 #define DMA_BUS_MODE_AAL	0x02000000
 
 /* DMA CRS Control and Status Register Mapping */

drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c

@@ -30,8 +30,8 @@
 #include "dwmac1000.h"
 #include "dwmac_dma.h"
 
-static int dwmac1000_dma_init(void __iomem *ioaddr, int pbl, u32 dma_tx,
-			      u32 dma_rx)
+static int dwmac1000_dma_init(void __iomem *ioaddr, int pbl, int fb,
+			      int burst_len, u32 dma_tx, u32 dma_rx)
 {
 	u32 value = readl(ioaddr + DMA_BUS_MODE);
 	int limit;
@@ -48,15 +48,47 @@ static int dwmac1000_dma_init(void __iomem *ioaddr, int pbl, u32 dma_tx,
 	if (limit < 0)
 		return -EBUSY;
 
-	value = /* DMA_BUS_MODE_FB | */ DMA_BUS_MODE_4PBL |
-	    ((pbl << DMA_BUS_MODE_PBL_SHIFT) |
-	     (pbl << DMA_BUS_MODE_RPBL_SHIFT));
+	/*
+	 * Set the DMA PBL (Programmable Burst Length) mode
+	 * Before stmmac core 3.50 this mode bit was 4xPBL, and
+	 * post 3.5 mode bit acts as 8*PBL.
+	 * For core rev < 3.5, when the core is set for 4xPBL mode, the
+	 * DMA transfers the data in 4, 8, 16, 32, 64 & 128 beats
+	 * depending on pbl value.
+	 * For core rev > 3.5, when the core is set for 8xPBL mode, the
+	 * DMA transfers the data in 8, 16, 32, 64, 128 & 256 beats
+	 * depending on pbl value.
+	 */
+	value = DMA_BUS_MODE_PBL | ((pbl << DMA_BUS_MODE_PBL_SHIFT) |
+		(pbl << DMA_BUS_MODE_RPBL_SHIFT));
+
+	/* Set the Fixed burst mode */
+	if (fb)
+		value |= DMA_BUS_MODE_FB;
 
 #ifdef CONFIG_STMMAC_DA
 	value |= DMA_BUS_MODE_DA;	/* Rx has priority over tx */
 #endif
 	writel(value, ioaddr + DMA_BUS_MODE);
 
+	/* In case of GMAC AXI configuration, program the DMA_AXI_BUS_MODE
+	 * for supported bursts.
+	 *
+	 * Note: This is applicable only for revision GMACv3.61a. For
+	 * older version this register is reserved and shall have no
+	 * effect.
+	 *
+	 * Note:
+	 *  For Fixed Burst Mode: if we directly write 0xFF to this
+	 *  register using the configurations pass from platform code,
+	 *  this would ensure that all bursts supported by core are set
+	 *  and those which are not supported would remain ineffective.
+	 *
+	 *  For Non Fixed Burst Mode: provide the maximum value of the
+	 *  burst length. Any burst equal or below the provided burst
+	 *  length would be allowed to perform. */
+	writel(burst_len, ioaddr + DMA_AXI_BUS_MODE);
+
 	/* Mask interrupts by writing to CSR7 */
 	writel(DMA_INTR_DEFAULT_MASK, ioaddr + DMA_INTR_ENA);
 

drivers/net/ethernet/stmicro/stmmac/dwmac100_dma.c

@@ -32,8 +32,8 @@
 #include "dwmac100.h"
 #include "dwmac_dma.h"
 
-static int dwmac100_dma_init(void __iomem *ioaddr, int pbl, u32 dma_tx,
-			     u32 dma_rx)
+static int dwmac100_dma_init(void __iomem *ioaddr, int pbl, int fb,
+			     int burst_len, u32 dma_tx, u32 dma_rx)
 {
 	u32 value = readl(ioaddr + DMA_BUS_MODE);
 	int limit;
@@ -52,7 +52,7 @@ static int dwmac100_dma_init(void __iomem *ioaddr, int pbl, u32 dma_tx,
 
 	/* Enable Application Access by writing to DMA CSR0 */
 	writel(DMA_BUS_MODE_DEFAULT | (pbl << DMA_BUS_MODE_PBL_SHIFT),
-	       ioaddr + DMA_BUS_MODE);
+			ioaddr + DMA_BUS_MODE);
 
 	/* Mask interrupts by writing to CSR7 */
 	writel(DMA_INTR_DEFAULT_MASK, ioaddr + DMA_INTR_ENA);

drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h

@@ -32,6 +32,7 @@
 #define DMA_CONTROL		0x00001018	/* Ctrl (Operational Mode) */
 #define DMA_INTR_ENA		0x0000101c	/* Interrupt Enable */
 #define DMA_MISSED_FRAME_CTR	0x00001020	/* Missed Frame Counter */
+#define DMA_AXI_BUS_MODE       0x00001028      /* AXI Bus Mode */
 #define DMA_CUR_TX_BUF_ADDR	0x00001050	/* Current Host Tx Buffer */
 #define DMA_CUR_RX_BUF_ADDR	0x00001054	/* Current Host Rx Buffer */
 #define DMA_HW_FEATURE		0x00001058	/* HW Feature Register */

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -944,7 +944,9 @@ static int stmmac_open(struct net_device *dev)
 	init_dma_desc_rings(dev);
 
 	/* DMA initialization and SW reset */
-	ret = priv->hw->dma->init(priv->ioaddr, priv->plat->pbl,
+	ret = priv->hw->dma->init(priv->ioaddr, priv->plat->dma_cfg->pbl,
+				  priv->plat->dma_cfg->fixed_burst,
+				  priv->plat->dma_cfg->burst_len,
 				  priv->dma_tx_phy, priv->dma_rx_phy);
 	if (ret < 0) {
 		pr_err("%s: DMA initialization failed\n", __func__);

drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c

@@ -35,7 +35,8 @@ static void stmmac_default_data(void)
 	plat_dat.bus_id = 1;
 	plat_dat.phy_addr = 0;
 	plat_dat.interface = PHY_INTERFACE_MODE_GMII;
-	plat_dat.pbl = 32;
+	plat_dat.dma_cfg->pbl = 32;
+	plat_dat.dma_cfg->burst_len = DMA_AXI_BLEN_256;
 	plat_dat.clk_csr = 2;	/* clk_csr_i = 20-35MHz & MDC = clk_csr_i/16 */
 	plat_dat.has_gmac = 1;
 	plat_dat.force_sf_dma_mode = 1;

include/linux/stmmac.h

@@ -60,6 +60,18 @@
  * 1110 clk_csr_i/16
  * 1111 clk_csr_i/18 */
 
+/* AXI DMA Burst length suported */
+#define DMA_AXI_BLEN_4		(1 << 1)
+#define DMA_AXI_BLEN_8		(1 << 2)
+#define DMA_AXI_BLEN_16		(1 << 3)
+#define DMA_AXI_BLEN_32		(1 << 4)
+#define DMA_AXI_BLEN_64		(1 << 5)
+#define DMA_AXI_BLEN_128	(1 << 6)
+#define DMA_AXI_BLEN_256	(1 << 7)
+#define DMA_AXI_BLEN_ALL (DMA_AXI_BLEN_4 | DMA_AXI_BLEN_8 | DMA_AXI_BLEN_16 \
+			| DMA_AXI_BLEN_32 | DMA_AXI_BLEN_64 \
+			| DMA_AXI_BLEN_128 | DMA_AXI_BLEN_256)
+
 /* Platfrom data for platform device structure's platform_data field */
 
 struct stmmac_mdio_bus_data {
@@ -70,13 +82,19 @@ struct stmmac_mdio_bus_data {
 	int probed_phy_irq;
 };
 
+struct stmmac_dma_cfg {
+	int pbl;
+	int fixed_burst;
+	int burst_len;
+};
+
 struct plat_stmmacenet_data {
 	char *phy_bus_name;
 	int bus_id;
 	int phy_addr;
 	int interface;
 	struct stmmac_mdio_bus_data *mdio_bus_data;
-	int pbl;
+	struct stmmac_dma_cfg *dma_cfg;
 	int clk_csr;
 	int has_gmac;
 	int enh_desc;