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>

1 files changed, 21 insertions, 3 deletions

diff --git a/Documentation/networking/stmmac.txt b/Documentation/networking/stmmac.txt
index 61f40a3fa7ea..eacb640286b1 100644
--- a/Documentation/networking/stmmac.txt
+++ b/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,